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-rw-r--r--tvix/glue/Cargo.toml63
-rw-r--r--tvix/glue/benches/eval.rs51
-rw-r--r--tvix/glue/default.nix8
-rw-r--r--tvix/glue/src/builtins/derivation.rs88
-rw-r--r--tvix/glue/src/builtins/errors.rs8
-rw-r--r--tvix/glue/src/builtins/fetchers.rs3
-rw-r--r--tvix/glue/src/builtins/import.rs425
-rw-r--r--tvix/glue/src/builtins/mod.rs76
-rw-r--r--tvix/glue/src/fetchers/mod.rs47
-rw-r--r--tvix/glue/src/known_paths.rs126
-rw-r--r--tvix/glue/src/lib.rs17
-rw-r--r--tvix/glue/src/refscan.rs115
-rw-r--r--tvix/glue/src/tests/dummy/.keep0
-rw-r--r--tvix/glue/src/tests/mod.rs33
-rw-r--r--tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.exp2
-rw-r--r--tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.nix1
-rw-r--r--tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.exp1
-rw-r--r--tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.nix8
-rw-r--r--tvix/glue/src/tests/tvix_tests/eval-okay-toxml-context.nix2
-rw-r--r--tvix/glue/src/tvix_build.rs217
-rw-r--r--tvix/glue/src/tvix_io.rs6
-rw-r--r--tvix/glue/src/tvix_store_io.rs321
22 files changed, 766 insertions, 852 deletions
diff --git a/tvix/glue/Cargo.toml b/tvix/glue/Cargo.toml
index 6968210c5efb..5fac947125af 100644
--- a/tvix/glue/Cargo.toml
+++ b/tvix/glue/Cargo.toml
@@ -4,48 +4,43 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-async-compression = { version = "0.4.9", features = ["tokio", "gzip", "bzip2", "xz"]}
-bstr = "1.6.0"
-bytes = "1.4.0"
-data-encoding = "2.3.3"
-futures = "0.3.30"
-magic = "0.16.2"
+async-compression = { workspace = true, features = ["tokio", "gzip", "bzip2", "xz"] }
+bstr = { workspace = true }
+bytes = { workspace = true }
+data-encoding = { workspace = true }
+futures = { workspace = true }
+magic = { workspace = true }
 nix-compat = { path = "../nix-compat" }
-pin-project = "1.1"
-reqwest = { version = "0.11.22", features = ["rustls-tls-native-roots"], default-features = false }
+pin-project = { workspace = true }
+reqwest = { workspace = true, features = ["rustls-tls-native-roots"] }
 tvix-build = { path = "../build", default-features = false, features = []}
 tvix-eval = { path = "../eval" }
 tvix-castore = { path = "../castore" }
 tvix-store = { path = "../store", default-features = false, features = []}
 tvix-tracing = { path = "../tracing" }
-tracing = "0.1.37"
-tracing-indicatif = "0.3.6"
-tokio = "1.28.0"
-tokio-tar = "0.3.1"
-tokio-util = { version = "0.7.9", features = ["io", "io-util", "compat"] }
-thiserror = "1.0.38"
-serde = "1.0.195"
-serde_json = "1.0"
-sha2 = "0.10.8"
-sha1 = "0.10.6"
-md-5 = "0.10.6"
-url = "2.4.0"
-walkdir = "2.4.0"
-
-[dependencies.wu-manber]
-git = "https://github.com/tvlfyi/wu-manber.git"
-
-[target.'cfg(not(target_env = "msvc"))'.dependencies]
-tikv-jemallocator = "0.5"
+tracing = { workspace = true }
+tracing-indicatif = { workspace = true }
+tokio = { workspace = true }
+tokio-tar = { workspace = true }
+tokio-util = { workspace = true, features = ["io", "io-util", "compat"] }
+thiserror = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+sha2 = { workspace = true }
+sha1 = { workspace = true }
+md-5 = { workspace = true }
+url = { workspace = true }
+walkdir = { workspace = true }
+clap = { workspace = true }
 
 [dev-dependencies]
-criterion = { version = "0.5", features = ["html_reports"] }
-hex-literal = "0.4.1"
-lazy_static = "1.4.0"
-nix = { version = "0.27.1", features = [ "fs" ] }
-pretty_assertions = "1.4.0"
-rstest = "0.19.0"
-tempfile = "3.8.1"
+criterion = { workspace = true, features = ["html_reports"] }
+hex-literal = { workspace = true }
+mimalloc = { workspace = true }
+nix = { workspace = true, features = ["fs"] }
+pretty_assertions = { workspace = true }
+rstest = { workspace = true }
+tempfile = { workspace = true }
 
 [features]
 default = ["nix_tests"]
diff --git a/tvix/glue/benches/eval.rs b/tvix/glue/benches/eval.rs
index 9e0154cad787..ce14bdcc13ec 100644
--- a/tvix/glue/benches/eval.rs
+++ b/tvix/glue/benches/eval.rs
@@ -1,8 +1,8 @@
+use clap::Parser;
 use criterion::{black_box, criterion_group, criterion_main, Criterion};
-use lazy_static::lazy_static;
+use mimalloc::MiMalloc;
+use std::sync::LazyLock;
 use std::{env, rc::Rc, sync::Arc, time::Duration};
-#[cfg(not(target_env = "msvc"))]
-use tikv_jemallocator::Jemalloc;
 use tvix_build::buildservice::DummyBuildService;
 use tvix_eval::{builtins::impure_builtins, EvalIO};
 use tvix_glue::{
@@ -11,15 +11,13 @@ use tvix_glue::{
     tvix_io::TvixIO,
     tvix_store_io::TvixStoreIO,
 };
-use tvix_store::utils::construct_services;
+use tvix_store::utils::{construct_services, ServiceUrlsMemory};
 
-#[cfg(not(target_env = "msvc"))]
 #[global_allocator]
-static GLOBAL: Jemalloc = Jemalloc;
+static GLOBAL: MiMalloc = MiMalloc;
 
-lazy_static! {
-    static ref TOKIO_RUNTIME: tokio::runtime::Runtime = tokio::runtime::Runtime::new().unwrap();
-}
+static TOKIO_RUNTIME: LazyLock<tokio::runtime::Runtime> =
+    LazyLock::new(|| tokio::runtime::Runtime::new().unwrap());
 
 fn interpret(code: &str) {
     // TODO: this is a bit annoying.
@@ -27,38 +25,41 @@ fn interpret(code: &str) {
     // piece of code. b/262
     let (blob_service, directory_service, path_info_service, nar_calculation_service) =
         TOKIO_RUNTIME
-            .block_on(async { construct_services("memory://", "memory://", "memory://").await })
+            .block_on(async {
+                construct_services(ServiceUrlsMemory::parse_from(std::iter::empty::<&str>())).await
+            })
             .unwrap();
 
     // We assemble a complete store in memory.
     let tvix_store_io = Rc::new(TvixStoreIO::new(
         blob_service,
         directory_service,
-        path_info_service.into(),
+        path_info_service,
         nar_calculation_service.into(),
         Arc::<DummyBuildService>::default(),
         TOKIO_RUNTIME.handle().clone(),
     ));
 
-    let mut eval = tvix_eval::Evaluation::new(
-        Box::new(TvixIO::new(tvix_store_io.clone() as Rc<dyn EvalIO>)) as Box<dyn EvalIO>,
-        true,
-    );
+    let mut eval_builder = tvix_eval::Evaluation::builder(Box::new(TvixIO::new(
+        tvix_store_io.clone() as Rc<dyn EvalIO>,
+    )) as Box<dyn EvalIO>)
+    .enable_import()
+    .add_builtins(impure_builtins());
 
-    eval.builtins.extend(impure_builtins());
-    add_derivation_builtins(&mut eval, Rc::clone(&tvix_store_io));
-    add_fetcher_builtins(&mut eval, Rc::clone(&tvix_store_io));
-    add_import_builtins(&mut eval, tvix_store_io);
-    configure_nix_path(
-        &mut eval,
+    eval_builder = add_derivation_builtins(eval_builder, Rc::clone(&tvix_store_io));
+    eval_builder = add_fetcher_builtins(eval_builder, Rc::clone(&tvix_store_io));
+    eval_builder = add_import_builtins(eval_builder, tvix_store_io);
+    eval_builder = configure_nix_path(
+        eval_builder,
         // The benchmark requires TVIX_BENCH_NIX_PATH to be set, so barf out
         // early, rather than benchmarking tvix returning an error.
         &Some(env::var("TVIX_BENCH_NIX_PATH").expect("TVIX_BENCH_NIX_PATH must be set")),
     );
 
+    let eval = eval_builder.build();
     let result = eval.evaluate(code, None);
 
-    assert!(result.errors.is_empty());
+    assert!(result.errors.is_empty(), "{:#?}", result.errors);
 }
 
 fn eval_nixpkgs(c: &mut Criterion) {
@@ -67,6 +68,12 @@ fn eval_nixpkgs(c: &mut Criterion) {
             interpret(black_box("(import <nixpkgs> {}).hello.outPath"));
         })
     });
+
+    c.bench_function("firefox outpath", |b| {
+        b.iter(|| {
+            interpret(black_box("(import <nixpkgs> {}).firefox.outPath"));
+        })
+    });
 }
 
 criterion_group!(
diff --git a/tvix/glue/default.nix b/tvix/glue/default.nix
index 14c7e214f25b..0ead94a504c3 100644
--- a/tvix/glue/default.nix
+++ b/tvix/glue/default.nix
@@ -3,15 +3,15 @@
 (depot.tvix.crates.workspaceMembers.tvix-glue.build.override {
   runTests = true;
   testPreRun = ''
-    export SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt;
+    export SSL_CERT_FILE=/dev/null
   '';
 }).overrideAttrs (old: rec {
   meta.ci.targets = lib.filter (x: lib.hasPrefix "with-features" x || x == "no-features") (lib.attrNames passthru);
-  passthru = depot.tvix.utils.mkFeaturePowerset {
+  passthru = old.passthru // (depot.tvix.utils.mkFeaturePowerset {
     inherit (old) crateName;
     features = [ "nix_tests" ];
     override.testPreRun = ''
-      export SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt;
+      export SSL_CERT_FILE=/dev/null
     '';
-  };
+  });
 })
diff --git a/tvix/glue/src/builtins/derivation.rs b/tvix/glue/src/builtins/derivation.rs
index 473aa9d5e315..3048fd8390c2 100644
--- a/tvix/glue/src/builtins/derivation.rs
+++ b/tvix/glue/src/builtins/derivation.rs
@@ -179,12 +179,10 @@ pub(crate) mod derivation_builtins {
     use nix_compat::nixhash::CAHash;
     use nix_compat::store_path::{build_ca_path, hash_placeholder};
     use sha2::Sha256;
-    use tvix_castore::proto as castorepb;
-    use tvix_castore::proto::node::Node;
-    use tvix_castore::proto::FileNode;
+    use tvix_castore::Node;
     use tvix_eval::generators::Gen;
     use tvix_eval::{NixContext, NixContextElement, NixString};
-    use tvix_store::proto::{NarInfo, PathInfo};
+    use tvix_store::pathinfoservice::PathInfo;
 
     #[builtin("placeholder")]
     async fn builtin_placeholder(co: GenCo, input: Value) -> Result<Value, ErrorKind> {
@@ -302,7 +300,7 @@ pub(crate) mod derivation_builtins {
                     // Remove the original default `out` output.
                     drv.outputs.clear();
 
-                    let mut output_names = vec![];
+                    let mut output_names = Vec::with_capacity(outputs.len());
 
                     for output in outputs {
                         let output_name = generators::request_force(&co, output)
@@ -347,9 +345,9 @@ pub(crate) mod derivation_builtins {
                             input_context.mimic(&val_str);
 
                             if arg_name == "builder" {
-                                drv.builder = val_str.to_str()?.to_owned();
+                                val_str.to_str()?.clone_into(&mut drv.builder);
                             } else {
-                                drv.system = val_str.to_str()?.to_owned();
+                                val_str.to_str()?.clone_into(&mut drv.system);
                             }
 
                             // Either populate drv.environment or structured_attrs.
@@ -381,11 +379,7 @@ pub(crate) mod derivation_builtins {
                             return Ok(val);
                         }
 
-                        let (val_json, context) = match val.into_contextful_json(&co).await? {
-                            Ok(v) => v,
-                            Err(cek) => return Ok(Value::from(cek)),
-                        };
-
+                        let (val_json, context) = val.into_contextful_json(&co).await?;
                         input_context.extend(context.into_iter());
 
                         // No need to check for dups, we only iterate over every attribute name once
@@ -570,21 +564,11 @@ pub(crate) mod derivation_builtins {
             let blob_digest = blob_writer.close().await?;
             let ca_hash = CAHash::Text(Sha256::digest(&content).into());
 
-            let store_path =
-                build_ca_path(name.to_str()?, &ca_hash, content.iter_ctx_plain(), false)
-                    .map_err(|_e| {
-                        nix_compat::derivation::DerivationError::InvalidOutputName(
-                            name.to_str_lossy().into_owned(),
-                        )
-                    })
-                    .map_err(DerivationError::InvalidDerivation)?;
-
-            let root_node = Node::File(FileNode {
-                name: store_path.to_string().into(),
-                digest: blob_digest.into(),
+            let root_node = Node::File {
+                digest: blob_digest,
                 size: blob_size,
                 executable: false,
-            });
+            };
 
             // calculate the nar hash
             let (nar_size, nar_sha256) = state
@@ -593,40 +577,38 @@ pub(crate) mod derivation_builtins {
                 .await
                 .map_err(|e| ErrorKind::TvixError(Rc::new(e)))?;
 
-            // assemble references from plain context.
-            let reference_paths: Vec<StorePathRef> = content
-                .iter_ctx_plain()
-                .map(|elem| StorePathRef::from_absolute_path(elem.as_bytes()))
-                .collect::<Result<_, _>>()
-                .map_err(|e| ErrorKind::TvixError(Rc::new(e)))?;
-
             // persist via pathinfo service.
             state
                 .path_info_service
                 .put(PathInfo {
-                    node: Some(castorepb::Node {
-                        node: Some(root_node),
-                    }),
-                    references: reference_paths
-                        .iter()
-                        .map(|x| bytes::Bytes::copy_from_slice(x.digest()))
-                        .collect(),
-                    narinfo: Some(NarInfo {
-                        nar_size,
-                        nar_sha256: nar_sha256.to_vec().into(),
-                        signatures: vec![],
-                        reference_names: reference_paths
-                            .into_iter()
-                            .map(|x| x.to_string())
-                            .collect(),
-                        deriver: None,
-                        ca: Some(ca_hash.into()),
-                    }),
+                    store_path: build_ca_path(
+                        name.to_str()?,
+                        &ca_hash,
+                        content.iter_ctx_plain(),
+                        false,
+                    )
+                    .map_err(|_e| {
+                        nix_compat::derivation::DerivationError::InvalidOutputName(
+                            name.to_str_lossy().into_owned(),
+                        )
+                    })
+                    .map_err(DerivationError::InvalidDerivation)?,
+                    node: root_node,
+                    // assemble references from plain context.
+                    references: content
+                        .iter_ctx_plain()
+                        .map(|elem| StorePath::from_absolute_path(elem.as_bytes()))
+                        .collect::<Result<_, _>>()
+                        .map_err(|e| ErrorKind::TvixError(Rc::new(e)))?,
+                    nar_size,
+                    nar_sha256,
+                    signatures: vec![],
+                    deriver: None,
+                    ca: Some(ca_hash),
                 })
                 .await
-                .map_err(|e| ErrorKind::TvixError(Rc::new(e)))?;
-
-            Ok::<_, ErrorKind>(store_path)
+                .map_err(|e| ErrorKind::TvixError(Rc::new(e)))
+                .map(|path_info| path_info.store_path)
         })?;
 
         let abs_path = store_path.to_absolute_path();
diff --git a/tvix/glue/src/builtins/errors.rs b/tvix/glue/src/builtins/errors.rs
index af8a24e6abb8..ec85942bb1ee 100644
--- a/tvix/glue/src/builtins/errors.rs
+++ b/tvix/glue/src/builtins/errors.rs
@@ -64,13 +64,13 @@ pub enum FetcherError {
 #[derive(Debug, Error)]
 pub enum ImportError {
     #[error("non-file '{0}' cannot be imported in 'flat' mode")]
-    FlatImportOfNonFile(String),
+    FlatImportOfNonFile(PathBuf),
 
     #[error("hash mismatch at ingestion of '{0}', expected: '{1}', got: '{2}'")]
-    HashMismatch(String, NixHash, NixHash),
+    HashMismatch(PathBuf, NixHash, NixHash),
 
-    #[error("path '{}' is not in the Nix store", .0.display())]
-    PathNotInStore(PathBuf),
+    #[error("path '{}' is not absolute or invalid", .0.display())]
+    PathNotAbsoluteOrInvalid(PathBuf),
 }
 
 impl From<ImportError> for tvix_eval::ErrorKind {
diff --git a/tvix/glue/src/builtins/fetchers.rs b/tvix/glue/src/builtins/fetchers.rs
index 1ad43b383353..2d9b30586703 100644
--- a/tvix/glue/src/builtins/fetchers.rs
+++ b/tvix/glue/src/builtins/fetchers.rs
@@ -73,8 +73,7 @@ async fn extract_fetch_args(
     let sha256 = match sha256_str {
         Some(sha256_str) => {
             let nixhash = nixhash::from_str(&sha256_str, Some("sha256"))
-                // TODO: DerivationError::InvalidOutputHash should be moved to ErrorKind::InvalidHash and used here instead
-                .map_err(|e| ErrorKind::TvixError(Rc::new(e)))?;
+                .map_err(|e| ErrorKind::InvalidHash(e.to_string()))?;
 
             Some(nixhash.digest_as_bytes().try_into().expect("is sha256"))
         }
diff --git a/tvix/glue/src/builtins/import.rs b/tvix/glue/src/builtins/import.rs
index a3273eca15dc..83b91165c09e 100644
--- a/tvix/glue/src/builtins/import.rs
+++ b/tvix/glue/src/builtins/import.rs
@@ -1,8 +1,9 @@
 //! Implements builtins used to import paths in the store.
 
-use crate::builtins::errors::ImportError;
+use crate::tvix_store_io::TvixStoreIO;
 use std::path::Path;
 use tvix_castore::import::ingest_entries;
+use tvix_castore::Node;
 use tvix_eval::{
     builtin_macros::builtins,
     generators::{self, GenCo},
@@ -16,7 +17,7 @@ async fn filtered_ingest(
     co: GenCo,
     path: &Path,
     filter: Option<&Value>,
-) -> Result<tvix_castore::proto::node::Node, ErrorKind> {
+) -> Result<Node, ErrorKind> {
     let mut entries: Vec<walkdir::DirEntry> = vec![];
     let mut it = walkdir::WalkDir::new(path)
         .follow_links(false)
@@ -88,10 +89,11 @@ async fn filtered_ingest(
     let dir_entries = entries.into_iter().rev().map(Ok);
 
     state.tokio_handle.block_on(async {
-        let entries = tvix_castore::import::fs::dir_entries_to_ingestion_stream(
+        let entries = tvix_castore::import::fs::dir_entries_to_ingestion_stream::<'_, _, _, &[u8]>(
             &state.blob_service,
             dir_entries,
             path,
+            None, // TODO re-scan
         );
         ingest_entries(&state.directory_service, entries)
             .await
@@ -104,169 +106,134 @@ async fn filtered_ingest(
 
 #[builtins(state = "Rc<TvixStoreIO>")]
 mod import_builtins {
-    use std::os::unix::ffi::OsStrExt;
-    use std::rc::Rc;
-
     use super::*;
 
+    use crate::builtins::ImportError;
     use crate::tvix_store_io::TvixStoreIO;
+    use bstr::ByteSlice;
     use nix_compat::nixhash::{CAHash, NixHash};
-    use nix_compat::store_path::StorePath;
+    use nix_compat::store_path::{build_ca_path, StorePathRef};
     use sha2::Digest;
+    use std::rc::Rc;
     use tokio::io::AsyncWriteExt;
-    use tvix_castore::proto::node::Node;
-    use tvix_castore::proto::FileNode;
+    use tvix_eval::builtins::coerce_value_to_path;
     use tvix_eval::generators::Gen;
     use tvix_eval::{generators::GenCo, ErrorKind, Value};
     use tvix_eval::{FileType, NixContextElement, NixString};
+    use tvix_store::path_info::PathInfo;
 
-    #[builtin("path")]
-    async fn builtin_path(
+    // This is a helper used by both builtins.path and builtins.filterSource.
+    async fn import_helper(
         state: Rc<TvixStoreIO>,
         co: GenCo,
-        args: Value,
+        path: std::path::PathBuf,
+        name: Option<&Value>,
+        filter: Option<&Value>,
+        recursive_ingestion: bool,
+        expected_sha256: Option<[u8; 32]>,
     ) -> Result<Value, ErrorKind> {
-        let args = args.to_attrs()?;
-        let path = args.select_required("path")?;
-        let path = generators::request_force(&co, path.clone())
-            .await
-            .to_path()?;
-        let name: String = if let Some(name) = args.select("name") {
-            generators::request_force(&co, name.clone())
+        let name: String = match name {
+            Some(name) => generators::request_force(&co, name.clone())
                 .await
                 .to_str()?
                 .as_bstr()
-                .to_string()
-        } else {
-            tvix_store::import::path_to_name(&path)
+                .to_string(),
+            None => tvix_store::import::path_to_name(&path)
                 .expect("Failed to derive the default name out of the path")
-                .to_string()
+                .to_string(),
         };
-        let filter = args.select("filter");
-        let recursive_ingestion = args
-            .select("recursive")
-            .map(|r| r.as_bool())
-            .transpose()?
-            .unwrap_or(true); // Yes, yes, Nix, by default, puts `recursive = true;`.
-        let expected_sha256 = args
-            .select("sha256")
-            .map(|h| {
-                h.to_str().and_then(|expected| {
-                    let expected = expected.into_bstring().to_string();
-                    // TODO: ensure that we fail if this is not a valid str.
-                    nix_compat::nixhash::from_str(&expected, None).map_err(|_err| {
-                        // TODO: a better error would be nice, we use
-                        // DerivationError::InvalidOutputHash usually for derivation construction.
-                        // This is not a derivation construction, should we move it outside and
-                        // generalize?
-                        ErrorKind::TypeError {
-                            expected: "sha256",
-                            actual: "not a sha256",
-                        }
-                    })
-                })
-            })
-            .transpose()?;
-
-        // Check if the path points to a regular file.
-        // If it does, the filter function is never executed.
-        // TODO: follow symlinks and check their type instead
-        let (root_node, ca_hash) = match state.file_type(path.as_ref())? {
+        // As a first step, we ingest the contents, and get back a root node,
+        // and optionally the sha256 a flat file.
+        let (root_node, ca) = match std::fs::metadata(&path)?.file_type().into() {
+            // Check if the path points to a regular file.
+            // If it does, the filter function is never executed, and we copy to the blobservice directly.
+            // If recursive is false, we need to calculate the sha256 digest of the raw contents,
+            // as that affects the output path calculation.
             FileType::Regular => {
-                let mut file = state.open(path.as_ref())?;
-                // This is a single file, copy it to the blobservice directly.
-                let mut hash = sha2::Sha256::new();
+                let mut file = state.open(&path)?;
+
+                let mut flat_sha256 = (!recursive_ingestion).then(sha2::Sha256::new);
                 let mut blob_size = 0;
+
                 let mut blob_writer = state
                     .tokio_handle
                     .block_on(async { state.blob_service.open_write().await });
 
-                let mut buf = [0u8; 4096];
+                // read piece by piece and write to blob_writer.
+                // This is a bit manual due to EvalIO being sync, while everything else async.
+                {
+                    let mut buf = [0u8; 4096];
 
-                loop {
-                    // read bytes into buffer, break out if EOF
-                    let len = file.read(&mut buf)?;
-                    if len == 0 {
-                        break;
-                    }
-                    blob_size += len as u64;
+                    loop {
+                        // read bytes into buffer, break out if EOF
+                        let len = file.read(&mut buf)?;
+                        if len == 0 {
+                            break;
+                        }
+                        blob_size += len as u64;
 
-                    let data = &buf[0..len];
+                        let data = &buf[0..len];
 
-                    // add to blobwriter
-                    state
-                        .tokio_handle
-                        .block_on(async { blob_writer.write_all(data).await })?;
+                        // add to blobwriter
+                        state
+                            .tokio_handle
+                            .block_on(async { blob_writer.write_all(data).await })?;
 
-                    // update the sha256 hash function. We can skip that if we're not using it.
-                    if !recursive_ingestion {
-                        hash.update(data);
+                        // update blob_sha256 if needed.
+                        if let Some(h) = flat_sha256.as_mut() {
+                            h.update(data)
+                        }
                     }
                 }
 
-                // close the blob writer, get back the b3 digest.
-                let blob_digest = state
-                    .tokio_handle
-                    .block_on(async { blob_writer.close().await })?;
-
-                let root_node = Node::File(FileNode {
-                    // The name gets set further down, while constructing the PathInfo.
-                    name: "".into(),
-                    digest: blob_digest.into(),
-                    size: blob_size,
-                    executable: false,
-                });
-
-                let ca_hash = if recursive_ingestion {
-                    let (_nar_size, nar_sha256) = state
-                        .tokio_handle
-                        .block_on(async {
-                            state
-                                .nar_calculation_service
-                                .as_ref()
-                                .calculate_nar(&root_node)
-                                .await
-                        })
-                        .map_err(|e| tvix_eval::ErrorKind::TvixError(Rc::new(e)))?;
-                    CAHash::Nar(NixHash::Sha256(nar_sha256))
-                } else {
-                    CAHash::Flat(NixHash::Sha256(hash.finalize().into()))
-                };
-
-                (root_node, ca_hash)
+                // close the blob writer, construct the root node and the blob_sha256 (later used for output path calculation)
+                (
+                    Node::File {
+                        digest: state
+                            .tokio_handle
+                            .block_on(async { blob_writer.close().await })?,
+                        size: blob_size,
+                        executable: false,
+                    },
+                    {
+                        // If non-recursive ingestion is requested…
+                        if let Some(flat_sha256) = flat_sha256 {
+                            let actual_sha256 = flat_sha256.finalize().into();
+
+                            // compare the recorded flat hash with an upfront one if provided.
+                            if let Some(expected_sha256) = expected_sha256 {
+                                if actual_sha256 != expected_sha256 {
+                                    return Err(ImportError::HashMismatch(
+                                        path,
+                                        NixHash::Sha256(expected_sha256),
+                                        NixHash::Sha256(actual_sha256),
+                                    )
+                                    .into());
+                                }
+                            }
+
+                            Some(CAHash::Flat(NixHash::Sha256(actual_sha256)))
+                        } else {
+                            None
+                        }
+                    },
+                )
             }
 
-            FileType::Directory => {
-                if !recursive_ingestion {
-                    return Err(ImportError::FlatImportOfNonFile(
-                        path.to_string_lossy().to_string(),
-                    ))?;
-                }
-
-                // do the filtered ingest
-                let root_node = filtered_ingest(state.clone(), co, path.as_ref(), filter).await?;
-
-                // calculate the NAR sha256
-                let (_nar_size, nar_sha256) = state
-                    .tokio_handle
-                    .block_on(async {
-                        state
-                            .nar_calculation_service
-                            .as_ref()
-                            .calculate_nar(&root_node)
-                            .await
-                    })
-                    .map_err(|e| tvix_eval::ErrorKind::TvixError(Rc::new(e)))?;
-
-                let ca_hash = CAHash::Nar(NixHash::Sha256(nar_sha256));
-
-                (root_node, ca_hash)
+            FileType::Directory if !recursive_ingestion => {
+                return Err(ImportError::FlatImportOfNonFile(path))?
             }
+
+            // do the filtered ingest
+            FileType::Directory => (
+                filtered_ingest(state.clone(), co, path.as_ref(), filter).await?,
+                None,
+            ),
             FileType::Symlink => {
                 // FUTUREWORK: Nix follows a symlink if it's at the root,
                 // except if it's not resolve-able (NixOS/nix#7761).i
                 return Err(tvix_eval::ErrorKind::IO {
-                    path: Some(path.to_path_buf()),
+                    path: Some(path),
                     error: Rc::new(std::io::Error::new(
                         std::io::ErrorKind::Unsupported,
                         "builtins.path pointing to a symlink is ill-defined.",
@@ -275,7 +242,7 @@ mod import_builtins {
             }
             FileType::Unknown => {
                 return Err(tvix_eval::ErrorKind::IO {
-                    path: Some(path.to_path_buf()),
+                    path: Some(path),
                     error: Rc::new(std::io::Error::new(
                         std::io::ErrorKind::Unsupported,
                         "unsupported file type",
@@ -284,32 +251,67 @@ mod import_builtins {
             }
         };
 
-        let (path_info, _hash, output_path) = state.tokio_handle.block_on(async {
-            state
-                .node_to_path_info(name.as_ref(), path.as_ref(), &ca_hash, root_node)
-                .await
-        })?;
-
-        if let Some(expected_sha256) = expected_sha256 {
-            if *ca_hash.hash() != expected_sha256 {
-                Err(ImportError::HashMismatch(
-                    path.to_string_lossy().to_string(),
-                    expected_sha256,
-                    ca_hash.hash().into_owned(),
-                ))?;
+        // Calculate the NAR sha256.
+        let (nar_size, nar_sha256) = state
+            .tokio_handle
+            .block_on(async {
+                state
+                    .nar_calculation_service
+                    .as_ref()
+                    .calculate_nar(&root_node)
+                    .await
+            })
+            .map_err(|e| tvix_eval::ErrorKind::TvixError(Rc::new(e)))?;
+
+        // Calculate the CA hash for the recursive cases, this is only already
+        // `Some(_)` for flat ingestion.
+        let ca = match ca {
+            None => {
+                // If an upfront-expected NAR hash was specified, compare.
+                if let Some(expected_nar_sha256) = expected_sha256 {
+                    if expected_nar_sha256 != nar_sha256 {
+                        return Err(ImportError::HashMismatch(
+                            path,
+                            NixHash::Sha256(expected_nar_sha256),
+                            NixHash::Sha256(nar_sha256),
+                        )
+                        .into());
+                    }
+                }
+                CAHash::Nar(NixHash::Sha256(nar_sha256))
             }
-        }
+            Some(ca) => ca,
+        };
+
+        let store_path = build_ca_path(&name, &ca, Vec::<&str>::new(), false)
+            .map_err(|e| tvix_eval::ErrorKind::TvixError(Rc::new(e)))?;
 
-        state
+        let path_info = state
             .tokio_handle
-            .block_on(async { state.path_info_service.as_ref().put(path_info).await })
+            .block_on(async {
+                state
+                    .path_info_service
+                    .as_ref()
+                    .put(PathInfo {
+                        store_path,
+                        node: root_node,
+                        // There's no reference scanning on path contents ingested like this.
+                        references: vec![],
+                        nar_size,
+                        nar_sha256,
+                        signatures: vec![],
+                        deriver: None,
+                        ca: Some(ca),
+                    })
+                    .await
+            })
             .map_err(|e| tvix_eval::ErrorKind::IO {
-                path: Some(path.to_path_buf()),
+                path: Some(path),
                 error: Rc::new(e.into()),
             })?;
 
         // We need to attach context to the final output path.
-        let outpath = output_path.to_absolute_path();
+        let outpath = path_info.store_path.to_absolute_path();
 
         Ok(
             NixString::new_context_from(NixContextElement::Plain(outpath.clone()).into(), outpath)
@@ -317,45 +319,72 @@ mod import_builtins {
         )
     }
 
-    #[builtin("filterSource")]
-    async fn builtin_filter_source(
+    #[builtin("path")]
+    async fn builtin_path(
         state: Rc<TvixStoreIO>,
         co: GenCo,
-        #[lazy] filter: Value,
-        path: Value,
+        args: Value,
     ) -> Result<Value, ErrorKind> {
-        let p = path.to_path()?;
-        let root_node = filtered_ingest(Rc::clone(&state), co, &p, Some(&filter)).await?;
-        let name = tvix_store::import::path_to_name(&p)?;
+        let args = args.to_attrs()?;
 
-        let outpath = state
-            .tokio_handle
-            .block_on(async {
-                let (_, nar_sha256) = state
-                    .nar_calculation_service
-                    .as_ref()
-                    .calculate_nar(&root_node)
-                    .await?;
+        let path = match coerce_value_to_path(
+            &co,
+            generators::request_force(&co, args.select_required("path")?.clone()).await,
+        )
+        .await?
+        {
+            Ok(path) => path,
+            Err(cek) => return Ok(cek.into()),
+        };
 
-                state
-                    .register_node_in_path_info_service(
-                        name,
-                        &p,
-                        &CAHash::Nar(NixHash::Sha256(nar_sha256)),
-                        root_node,
-                    )
-                    .await
+        let filter = args.select("filter");
+
+        // Construct a sha256 hasher, which is needed for flat ingestion.
+        let recursive_ingestion = args
+            .select("recursive")
+            .map(|r| r.as_bool())
+            .transpose()?
+            .unwrap_or(true); // Yes, yes, Nix, by default, puts `recursive = true;`.
+
+        let expected_sha256 = args
+            .select("sha256")
+            .map(|h| {
+                h.to_str().and_then(|expected| {
+                    match nix_compat::nixhash::from_str(expected.to_str()?, Some("sha256")) {
+                        Ok(NixHash::Sha256(digest)) => Ok(digest),
+                        Ok(_) => unreachable!(),
+                        Err(e) => Err(ErrorKind::InvalidHash(e.to_string())),
+                    }
+                })
             })
-            .map_err(|err| ErrorKind::IO {
-                path: Some(p.to_path_buf()),
-                error: err.into(),
-            })?
-            .to_absolute_path();
+            .transpose()?;
 
-        Ok(
-            NixString::new_context_from(NixContextElement::Plain(outpath.clone()).into(), outpath)
-                .into(),
+        import_helper(
+            state,
+            co,
+            path,
+            args.select("name"),
+            filter,
+            recursive_ingestion,
+            expected_sha256,
         )
+        .await
+    }
+
+    #[builtin("filterSource")]
+    async fn builtin_filter_source(
+        state: Rc<TvixStoreIO>,
+        co: GenCo,
+        #[lazy] filter: Value,
+        path: Value,
+    ) -> Result<Value, ErrorKind> {
+        let path =
+            match coerce_value_to_path(&co, generators::request_force(&co, path).await).await? {
+                Ok(path) => path,
+                Err(cek) => return Ok(cek.into()),
+            };
+
+        import_helper(state, co, path, None, Some(&filter), true, None).await
     }
 
     #[builtin("storePath")]
@@ -364,39 +393,33 @@ mod import_builtins {
         co: GenCo,
         path: Value,
     ) -> Result<Value, ErrorKind> {
-        let p = std::str::from_utf8(match &path {
-            Value::String(s) => s.as_bytes(),
-            Value::Path(p) => p.as_os_str().as_bytes(),
+        let p = match &path {
+            Value::String(s) => Path::new(s.as_bytes().to_os_str()?),
+            Value::Path(p) => p.as_path(),
             _ => {
                 return Err(ErrorKind::TypeError {
                     expected: "string or path",
                     actual: path.type_of(),
                 })
             }
-        })?;
-
-        let path_exists = if let Ok((store_path, sub_path)) = StorePath::from_absolute_path_full(p)
-        {
-            if !sub_path.as_os_str().is_empty() {
-                false
-            } else {
-                state.store_path_exists(store_path.as_ref()).await?
-            }
-        } else {
-            false
         };
 
-        if !path_exists {
-            return Err(ImportError::PathNotInStore(p.into()).into());
-        }
+        // For this builtin, the path needs to start with an absolute store path.
+        let (store_path, _sub_path) = StorePathRef::from_absolute_path_full(p)
+            .map_err(|_e| ImportError::PathNotAbsoluteOrInvalid(p.to_path_buf()))?;
 
-        Ok(Value::String(NixString::new_context_from(
-            [NixContextElement::Plain(p.into())].into(),
-            p,
-        )))
+        if state.path_exists(p)? {
+            Ok(Value::String(NixString::new_context_from(
+                [NixContextElement::Plain(store_path.to_absolute_path())].into(),
+                p.as_os_str().as_encoded_bytes(),
+            )))
+        } else {
+            Err(ErrorKind::IO {
+                path: Some(p.to_path_buf()),
+                error: Rc::new(std::io::ErrorKind::NotFound.into()),
+            })
+        }
     }
 }
 
 pub use import_builtins::builtins as import_builtins;
-
-use crate::tvix_store_io::TvixStoreIO;
diff --git a/tvix/glue/src/builtins/mod.rs b/tvix/glue/src/builtins/mod.rs
index 3d6263286dc4..6149423acff0 100644
--- a/tvix/glue/src/builtins/mod.rs
+++ b/tvix/glue/src/builtins/mod.rs
@@ -18,13 +18,14 @@ pub use errors::{DerivationError, FetcherError, ImportError};
 ///
 /// As they need to interact with `known_paths`, we also need to pass in
 /// `known_paths`.
-pub fn add_derivation_builtins<IO>(eval: &mut tvix_eval::Evaluation<IO>, io: Rc<TvixStoreIO>) {
-    eval.builtins
-        .extend(derivation::derivation_builtins::builtins(Rc::clone(&io)));
-
-    // Add the actual `builtins.derivation` from compiled Nix code
-    eval.src_builtins
-        .push(("derivation", include_str!("derivation.nix")));
+pub fn add_derivation_builtins<'co, 'ro, 'env, IO>(
+    eval_builder: tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO>,
+    io: Rc<TvixStoreIO>,
+) -> tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO> {
+    eval_builder
+        .add_builtins(derivation::derivation_builtins::builtins(Rc::clone(&io)))
+        // Add the actual `builtins.derivation` from compiled Nix code
+        .add_src_builtin("derivation", include_str!("derivation.nix"))
 }
 
 /// Adds fetcher builtins to the passed [tvix_eval::Evaluation]:
@@ -32,9 +33,11 @@ pub fn add_derivation_builtins<IO>(eval: &mut tvix_eval::Evaluation<IO>, io: Rc<
 /// * `fetchurl`
 /// * `fetchTarball`
 /// * `fetchGit`
-pub fn add_fetcher_builtins<IO>(eval: &mut tvix_eval::Evaluation<IO>, io: Rc<TvixStoreIO>) {
-    eval.builtins
-        .extend(fetchers::fetcher_builtins::builtins(Rc::clone(&io)));
+pub fn add_fetcher_builtins<'co, 'ro, 'env, IO>(
+    eval_builder: tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO>,
+    io: Rc<TvixStoreIO>,
+) -> tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO> {
+    eval_builder.add_builtins(fetchers::fetcher_builtins::builtins(Rc::clone(&io)))
 }
 
 /// Adds import-related builtins to the passed [tvix_eval::Evaluation].
@@ -42,10 +45,12 @@ pub fn add_fetcher_builtins<IO>(eval: &mut tvix_eval::Evaluation<IO>, io: Rc<Tvi
 /// These are `filterSource` and `path`
 ///
 /// As they need to interact with the store implementation, we pass [`TvixStoreIO`].
-pub fn add_import_builtins<IO>(eval: &mut tvix_eval::Evaluation<IO>, io: Rc<TvixStoreIO>) {
-    eval.builtins.extend(import::import_builtins(io));
-
+pub fn add_import_builtins<'co, 'ro, 'env, IO>(
+    eval_builder: tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO>,
+    io: Rc<TvixStoreIO>,
+) -> tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO> {
     // TODO(raitobezarius): evaluate expressing filterSource as Nix code using path (b/372)
+    eval_builder.add_builtins(import::import_builtins(io))
 }
 
 #[cfg(test)]
@@ -55,12 +60,13 @@ mod tests {
     use crate::tvix_store_io::TvixStoreIO;
 
     use super::{add_derivation_builtins, add_fetcher_builtins, add_import_builtins};
+    use clap::Parser;
     use nix_compat::store_path::hash_placeholder;
     use rstest::rstest;
     use tempfile::TempDir;
     use tvix_build::buildservice::DummyBuildService;
     use tvix_eval::{EvalIO, EvaluationResult};
-    use tvix_store::utils::construct_services;
+    use tvix_store::utils::{construct_services, ServiceUrlsMemory};
 
     /// evaluates a given nix expression and returns the result.
     /// Takes care of setting up the evaluator so it knows about the
@@ -69,23 +75,25 @@ mod tests {
         // We assemble a complete store in memory.
         let runtime = tokio::runtime::Runtime::new().expect("Failed to build a Tokio runtime");
         let (blob_service, directory_service, path_info_service, nar_calculation_service) = runtime
-            .block_on(async { construct_services("memory://", "memory://", "memory://").await })
+            .block_on(async {
+                construct_services(ServiceUrlsMemory::parse_from(std::iter::empty::<&str>())).await
+            })
             .expect("Failed to construct store services in memory");
 
         let io = Rc::new(TvixStoreIO::new(
             blob_service,
             directory_service,
-            path_info_service.into(),
+            path_info_service,
             nar_calculation_service.into(),
             Arc::<DummyBuildService>::default(),
             runtime.handle().clone(),
         ));
 
-        let mut eval = tvix_eval::Evaluation::new(io.clone() as Rc<dyn EvalIO>, false);
-
-        add_derivation_builtins(&mut eval, Rc::clone(&io));
-        add_fetcher_builtins(&mut eval, Rc::clone(&io));
-        add_import_builtins(&mut eval, io);
+        let mut eval_builder = tvix_eval::Evaluation::builder(io.clone() as Rc<dyn EvalIO>);
+        eval_builder = add_derivation_builtins(eval_builder, Rc::clone(&io));
+        eval_builder = add_fetcher_builtins(eval_builder, Rc::clone(&io));
+        eval_builder = add_import_builtins(eval_builder, io);
+        let eval = eval_builder.build();
 
         // run the evaluation itself.
         eval.evaluate(str, None)
@@ -529,14 +537,13 @@ mod tests {
         assert!(eval_result.errors.is_empty(), "errors should be empty");
     }
 
-    // Space is an illegal character.
+    /// Space is an illegal character, but if we specify a name without spaces, it's ok.
     #[rstest]
-    #[case(
+    #[case::rename_success(
         r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = true; })"#,
         true
     )]
-    // Space is still an illegal character.
-    #[case(
+    #[case::rename_with_spaces_fail(
         r#"(builtins.path { name = "invalid name"; path = @fixtures + "/te st"; recursive = true; })"#,
         false
     )]
@@ -575,14 +582,13 @@ mod tests {
         }
     }
 
-    // Space is an illegal character.
+    /// Space is an illegal character, but if we specify a name without spaces, it's ok.
     #[rstest]
-    #[case(
+    #[case::rename_success(
         r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = false; })"#,
         true
     )]
-    // Space is still an illegal character.
-    #[case(
+    #[case::rename_with_spaces_fail(
         r#"(builtins.path { name = "invalid name"; path = @fixtures + "/te st"; recursive = false; })"#,
         false
     )]
@@ -623,20 +629,20 @@ mod tests {
     }
 
     #[rstest]
-    #[case(
+    #[case::flat_success(
         r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = false; sha256 = "sha256-47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="; })"#,
         true
     )]
-    #[case(
-        r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = true; sha256 = "sha256-47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="; })"#,
+    #[case::flat_fail(
+        r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = false; sha256 = "sha256-d6xi4mKdjkX2JFicDIv5niSzpyI0m/Hnm8GGAIU04kY="; })"#,
         false
     )]
-    #[case(
+    #[case::recursive_success(
         r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = true; sha256 = "sha256-d6xi4mKdjkX2JFicDIv5niSzpyI0m/Hnm8GGAIU04kY="; })"#,
         true
     )]
-    #[case(
-        r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = false; sha256 = "sha256-d6xi4mKdjkX2JFicDIv5niSzpyI0m/Hnm8GGAIU04kY="; })"#,
+    #[case::recursive_fail(
+        r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = true; sha256 = "sha256-47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="; })"#,
         false
     )]
     fn builtins_path_fod_locking(#[case] code: &str, #[case] exp_success: bool) {
diff --git a/tvix/glue/src/fetchers/mod.rs b/tvix/glue/src/fetchers/mod.rs
index eb035a5a905c..c12598e96328 100644
--- a/tvix/glue/src/fetchers/mod.rs
+++ b/tvix/glue/src/fetchers/mod.rs
@@ -10,12 +10,11 @@ use tokio::io::{AsyncBufRead, AsyncRead, AsyncWrite, AsyncWriteExt, BufReader};
 use tokio_util::io::{InspectReader, InspectWriter};
 use tracing::{instrument, warn, Span};
 use tracing_indicatif::span_ext::IndicatifSpanExt;
-use tvix_castore::{
-    blobservice::BlobService,
-    directoryservice::DirectoryService,
-    proto::{node::Node, FileNode},
+use tvix_castore::{blobservice::BlobService, directoryservice::DirectoryService, Node};
+use tvix_store::{
+    nar::NarCalculationService,
+    pathinfoservice::{PathInfo, PathInfoService},
 };
-use tvix_store::{nar::NarCalculationService, pathinfoservice::PathInfoService, proto::PathInfo};
 use url::Url;
 
 use crate::builtins::FetcherError;
@@ -331,12 +330,11 @@ where
 
                 // Construct and return the FileNode describing the downloaded contents.
                 Ok((
-                    Node::File(FileNode {
-                        name: vec![].into(),
-                        digest: blob_writer.close().await?.into(),
+                    Node::File {
+                        digest: blob_writer.close().await?,
                         size: blob_size,
                         executable: false,
-                    }),
+                    },
                     CAHash::Flat(actual_hash),
                     blob_size,
                 ))
@@ -531,12 +529,11 @@ where
 
                 // Construct and return the FileNode describing the downloaded contents,
                 // make it executable.
-                let root_node = Node::File(FileNode {
-                    name: vec![].into(),
-                    digest: blob_digest.into(),
+                let root_node = Node::File {
+                    digest: blob_digest,
                     size: file_size,
                     executable: true,
-                });
+                };
 
                 Ok((root_node, CAHash::Nar(actual_hash), file_size))
             }
@@ -560,9 +557,6 @@ where
         // Calculate the store path to return, by calculating from ca_hash.
         let store_path = build_ca_path(name, &ca_hash, Vec::<String>::new(), false)?;
 
-        // Rename the node name to match the Store Path.
-        let node = node.rename(store_path.to_string().into());
-
         // If the resulting hash is not a CAHash::Nar, we also need to invoke
         // `calculate_nar` to calculate this representation, as it's required in
         // the [PathInfo].
@@ -580,25 +574,22 @@ where
 
         // Construct the PathInfo and persist it.
         let path_info = PathInfo {
-            node: Some(tvix_castore::proto::Node { node: Some(node) }),
+            store_path: store_path.to_owned(),
+            node: node.clone(),
             references: vec![],
-            narinfo: Some(tvix_store::proto::NarInfo {
-                nar_size,
-                nar_sha256: nar_sha256.to_vec().into(),
-                signatures: vec![],
-                reference_names: vec![],
-                deriver: None,
-                ca: Some(ca_hash.into()),
-            }),
+            nar_size,
+            nar_sha256,
+            signatures: vec![],
+            deriver: None,
+            ca: Some(ca_hash),
         };
 
-        let path_info = self
-            .path_info_service
+        self.path_info_service
             .put(path_info)
             .await
             .map_err(|e| FetcherError::Io(e.into()))?;
 
-        Ok((store_path, path_info.node.unwrap().node.unwrap()))
+        Ok((store_path, node))
     }
 }
 
diff --git a/tvix/glue/src/known_paths.rs b/tvix/glue/src/known_paths.rs
index edc57c38f247..7934bfe0baa2 100644
--- a/tvix/glue/src/known_paths.rs
+++ b/tvix/glue/src/known_paths.rs
@@ -25,27 +25,27 @@ pub struct KnownPaths {
     ///
     /// Keys are derivation paths, values are a tuple of the "hash derivation
     /// modulo" and the Derivation struct itself.
-    derivations: HashMap<StorePath, ([u8; 32], Derivation)>,
+    derivations: HashMap<StorePath<String>, ([u8; 32], Derivation)>,
 
     /// A map from output path to (one) drv path.
     /// Note that in the case of FODs, multiple drvs can produce the same output
     /// path. We use one of them.
-    outputs_to_drvpath: HashMap<StorePath, StorePath>,
+    outputs_to_drvpath: HashMap<StorePath<String>, StorePath<String>>,
 
     /// A map from output path to fetches (and their names).
-    outputs_to_fetches: HashMap<StorePath, (String, Fetch)>,
+    outputs_to_fetches: HashMap<StorePath<String>, (String, Fetch)>,
 }
 
 impl KnownPaths {
     /// Fetch the opaque "hash derivation modulo" for a given derivation path.
-    pub fn get_hash_derivation_modulo(&self, drv_path: &StorePath) -> Option<&[u8; 32]> {
+    pub fn get_hash_derivation_modulo(&self, drv_path: &StorePath<String>) -> Option<&[u8; 32]> {
         self.derivations
             .get(drv_path)
             .map(|(hash_derivation_modulo, _derivation)| hash_derivation_modulo)
     }
 
     /// Return a reference to the Derivation for a given drv path.
-    pub fn get_drv_by_drvpath(&self, drv_path: &StorePath) -> Option<&Derivation> {
+    pub fn get_drv_by_drvpath(&self, drv_path: &StorePath<String>) -> Option<&Derivation> {
         self.derivations
             .get(drv_path)
             .map(|(_hash_derivation_modulo, derivation)| derivation)
@@ -54,7 +54,10 @@ impl KnownPaths {
     /// Return the drv path of the derivation producing the passed output path.
     /// Note there can be multiple Derivations producing the same output path in
     /// flight; this function will only return one of them.
-    pub fn get_drv_path_for_output_path(&self, output_path: &StorePath) -> Option<&StorePath> {
+    pub fn get_drv_path_for_output_path(
+        &self,
+        output_path: &StorePath<String>,
+    ) -> Option<&StorePath<String>> {
         self.outputs_to_drvpath.get(output_path)
     }
 
@@ -63,7 +66,7 @@ impl KnownPaths {
     /// be fully calculated.
     /// All input derivations this refers to must also be inserted to this
     /// struct.
-    pub fn add_derivation(&mut self, drv_path: StorePath, drv: Derivation) {
+    pub fn add_derivation(&mut self, drv_path: StorePath<String>, drv: Derivation) {
         // check input derivations to have been inserted.
         #[cfg(debug_assertions)]
         {
@@ -124,57 +127,86 @@ impl KnownPaths {
 
     /// Return the name and fetch producing the passed output path.
     /// Note there can also be (multiple) Derivations producing the same output path.
-    pub fn get_fetch_for_output_path(&self, output_path: &StorePath) -> Option<(String, Fetch)> {
+    pub fn get_fetch_for_output_path(
+        &self,
+        output_path: &StorePath<String>,
+    ) -> Option<(String, Fetch)> {
         self.outputs_to_fetches
             .get(output_path)
             .map(|(name, fetch)| (name.to_owned(), fetch.to_owned()))
     }
+
+    /// Returns an iterator over all known derivations and their store path.
+    pub fn get_derivations(&self) -> impl Iterator<Item = (&StorePath<String>, &Derivation)> {
+        self.derivations.iter().map(|(k, v)| (k, &v.1))
+    }
 }
 
 #[cfg(test)]
 mod tests {
+    use std::sync::LazyLock;
+
+    use hex_literal::hex;
     use nix_compat::{derivation::Derivation, nixbase32, nixhash, store_path::StorePath};
     use url::Url;
 
-    use crate::fetchers::Fetch;
-
     use super::KnownPaths;
-    use hex_literal::hex;
-    use lazy_static::lazy_static;
+    use crate::fetchers::Fetch;
 
-    lazy_static! {
-        static ref BAR_DRV: Derivation = Derivation::from_aterm_bytes(include_bytes!(
+    static BAR_DRV: LazyLock<Derivation> = LazyLock::new(|| {
+        Derivation::from_aterm_bytes(include_bytes!(
             "tests/ss2p4wmxijn652haqyd7dckxwl4c7hxx-bar.drv"
         ))
-        .expect("must parse");
-        static ref FOO_DRV: Derivation = Derivation::from_aterm_bytes(include_bytes!(
+        .expect("must parse")
+    });
+
+    static FOO_DRV: LazyLock<Derivation> = LazyLock::new(|| {
+        Derivation::from_aterm_bytes(include_bytes!(
             "tests/ch49594n9avinrf8ip0aslidkc4lxkqv-foo.drv"
         ))
-        .expect("must parse");
-        static ref BAR_DRV_PATH: StorePath =
-            StorePath::from_bytes(b"ss2p4wmxijn652haqyd7dckxwl4c7hxx-bar.drv").expect("must parse");
-        static ref FOO_DRV_PATH: StorePath =
-            StorePath::from_bytes(b"ch49594n9avinrf8ip0aslidkc4lxkqv-foo.drv").expect("must parse");
-        static ref BAR_OUT_PATH: StorePath =
-            StorePath::from_bytes(b"mp57d33657rf34lzvlbpfa1gjfv5gmpg-bar").expect("must parse");
-        static ref FOO_OUT_PATH: StorePath =
-            StorePath::from_bytes(b"fhaj6gmwns62s6ypkcldbaj2ybvkhx3p-foo").expect("must parse");
-
-        static ref FETCH_URL : Fetch = Fetch::URL{
-            url: Url::parse("https://raw.githubusercontent.com/aaptel/notmuch-extract-patch/f732a53e12a7c91a06755ebfab2007adc9b3063b/notmuch-extract-patch").unwrap(),
-            exp_hash: Some(nixhash::from_sri_str("sha256-Xa1Jbl2Eq5+L0ww+Ph1osA3Z/Dxe/RkN1/dITQCdXFk=").unwrap())
-        };
-        static ref FETCH_URL_OUT_PATH: StorePath = StorePath::from_bytes(b"06qi00hylriyfm0nl827crgjvbax84mz-notmuch-extract-patch").unwrap();
-
-        static ref FETCH_TARBALL : Fetch = Fetch::Tarball{
-            url: Url::parse("https://github.com/NixOS/nixpkgs/archive/91050ea1e57e50388fa87a3302ba12d188ef723a.tar.gz").unwrap(),
-            exp_nar_sha256: Some(nixbase32::decode_fixed("1hf6cgaci1n186kkkjq106ryf8mmlq9vnwgfwh625wa8hfgdn4dm").unwrap())
-        };
-        static ref FETCH_TARBALL_OUT_PATH: StorePath = StorePath::from_bytes(b"7adgvk5zdfq4pwrhsm3n9lzypb12gw0g-source").unwrap();
+        .expect("must parse")
+    });
+
+    static BAR_DRV_PATH: LazyLock<StorePath<String>> = LazyLock::new(|| {
+        StorePath::from_bytes(b"ss2p4wmxijn652haqyd7dckxwl4c7hxx-bar.drv").expect("must parse")
+    });
+
+    static FOO_DRV_PATH: LazyLock<StorePath<String>> = LazyLock::new(|| {
+        StorePath::from_bytes(b"ch49594n9avinrf8ip0aslidkc4lxkqv-foo.drv").expect("must parse")
+    });
+
+    static BAR_OUT_PATH: LazyLock<StorePath<String>> = LazyLock::new(|| {
+        StorePath::from_bytes(b"mp57d33657rf34lzvlbpfa1gjfv5gmpg-bar").expect("must parse")
+    });
+
+    static FOO_OUT_PATH: LazyLock<StorePath<String>> = LazyLock::new(|| {
+        StorePath::from_bytes(b"fhaj6gmwns62s6ypkcldbaj2ybvkhx3p-foo").expect("must parse")
+    });
+
+    static FETCH_URL: LazyLock<Fetch> = LazyLock::new(|| {
+        Fetch::URL {
+        url: Url::parse("https://raw.githubusercontent.com/aaptel/notmuch-extract-patch/f732a53e12a7c91a06755ebfab2007adc9b3063b/notmuch-extract-patch").unwrap(),
+        exp_hash: Some(nixhash::from_sri_str("sha256-Xa1Jbl2Eq5+L0ww+Ph1osA3Z/Dxe/RkN1/dITQCdXFk=").unwrap())
     }
+    });
+
+    static FETCH_URL_OUT_PATH: LazyLock<StorePath<String>> = LazyLock::new(|| {
+        StorePath::from_bytes(b"06qi00hylriyfm0nl827crgjvbax84mz-notmuch-extract-patch").unwrap()
+    });
 
-    /// ensure we don't allow acdding a Derivation that depends on another,
-    /// not-yet-added Derivation.
+    static FETCH_TARBALL: LazyLock<Fetch> = LazyLock::new(|| {
+        Fetch::Tarball {
+        url: Url::parse("https://github.com/NixOS/nixpkgs/archive/91050ea1e57e50388fa87a3302ba12d188ef723a.tar.gz").unwrap(),
+        exp_nar_sha256: Some(nixbase32::decode_fixed("1hf6cgaci1n186kkkjq106ryf8mmlq9vnwgfwh625wa8hfgdn4dm").unwrap())
+    }
+    });
+
+    static FETCH_TARBALL_OUT_PATH: LazyLock<StorePath<String>> = LazyLock::new(|| {
+        StorePath::from_bytes(b"7adgvk5zdfq4pwrhsm3n9lzypb12gw0g-source").unwrap()
+    });
+
+    /// Ensure that we don't allow adding a derivation that depends on another,
+    /// not-yet-added derivation.
     #[test]
     #[should_panic]
     fn drv_reject_if_missing_input_drv() {
@@ -269,5 +301,21 @@ mod tests {
         );
     }
 
+    #[test]
+    fn get_derivations_working() {
+        let mut known_paths = KnownPaths::default();
+
+        // Add BAR_DRV
+        known_paths.add_derivation(BAR_DRV_PATH.clone(), BAR_DRV.clone());
+
+        // We should be able to find BAR_DRV_PATH and BAR_DRV as a pair in get_derivations.
+        assert_eq!(
+            Some((&BAR_DRV_PATH.clone(), &BAR_DRV.clone())),
+            known_paths
+                .get_derivations()
+                .find(|(s, d)| (*s, *d) == (&BAR_DRV_PATH, &BAR_DRV))
+        );
+    }
+
     // TODO: add test panicking about missing digest
 }
diff --git a/tvix/glue/src/lib.rs b/tvix/glue/src/lib.rs
index a5dbdb8742fc..320d1f6fede2 100644
--- a/tvix/glue/src/lib.rs
+++ b/tvix/glue/src/lib.rs
@@ -1,7 +1,6 @@
 pub mod builtins;
 pub mod fetchers;
 pub mod known_paths;
-pub mod refscan;
 pub mod tvix_build;
 pub mod tvix_io;
 pub mod tvix_store_io;
@@ -14,12 +13,14 @@ mod tests;
 /// Tell the Evaluator to resolve `<nix>` to the path `/__corepkgs__`,
 /// which has special handling in [tvix_io::TvixIO].
 /// This is used in nixpkgs to import `fetchurl.nix` from `<nix>`.
-pub fn configure_nix_path<IO>(
-    eval: &mut tvix_eval::Evaluation<IO>,
+pub fn configure_nix_path<'co, 'ro, 'env, IO>(
+    eval_builder: tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO>,
     nix_search_path: &Option<String>,
-) {
-    eval.nix_path = nix_search_path
-        .as_ref()
-        .map(|p| format!("nix=/__corepkgs__:{}", p))
-        .or_else(|| Some("nix=/__corepkgs__".to_string()));
+) -> tvix_eval::EvaluationBuilder<'co, 'ro, 'env, IO> {
+    eval_builder.nix_path(
+        nix_search_path
+            .as_ref()
+            .map(|p| format!("nix=/__corepkgs__:{}", p))
+            .or_else(|| Some("nix=/__corepkgs__".to_string())),
+    )
 }
diff --git a/tvix/glue/src/refscan.rs b/tvix/glue/src/refscan.rs
deleted file mode 100644
index 0e0bb6c77828..000000000000
--- a/tvix/glue/src/refscan.rs
+++ /dev/null
@@ -1,115 +0,0 @@
-//! Simple scanner for non-overlapping, known references of Nix store paths in a
-//! given string.
-//!
-//! This is used for determining build references (see
-//! //tvix/eval/docs/build-references.md for more details).
-//!
-//! The scanner itself is using the Wu-Manber string-matching algorithm, using
-//! our fork of the `wu-mamber` crate.
-
-use std::collections::BTreeSet;
-use wu_manber::TwoByteWM;
-
-pub const STORE_PATH_LEN: usize = "/nix/store/00000000000000000000000000000000".len();
-
-/// Represents a "primed" reference scanner with an automaton that knows the set
-/// of store paths to scan for.
-pub struct ReferenceScanner<P: Ord + AsRef<[u8]>> {
-    candidates: Vec<P>,
-    searcher: Option<TwoByteWM>,
-    matches: Vec<usize>,
-}
-
-impl<P: Clone + Ord + AsRef<[u8]>> ReferenceScanner<P> {
-    /// Construct a new `ReferenceScanner` that knows how to scan for the given
-    /// candidate store paths.
-    pub fn new(candidates: Vec<P>) -> Self {
-        let searcher = if candidates.is_empty() {
-            None
-        } else {
-            Some(TwoByteWM::new(&candidates))
-        };
-
-        ReferenceScanner {
-            searcher,
-            candidates,
-            matches: Default::default(),
-        }
-    }
-
-    /// Scan the given str for all non-overlapping matches and collect them
-    /// in the scanner.
-    pub fn scan<S: AsRef<[u8]>>(&mut self, haystack: S) {
-        if haystack.as_ref().len() < STORE_PATH_LEN {
-            return;
-        }
-
-        if let Some(searcher) = &self.searcher {
-            for m in searcher.find(haystack) {
-                self.matches.push(m.pat_idx);
-            }
-        }
-    }
-
-    /// Finalise the reference scanner and return the resulting matches.
-    pub fn finalise(self) -> BTreeSet<P> {
-        self.matches
-            .into_iter()
-            .map(|idx| self.candidates[idx].clone())
-            .collect()
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    // The actual derivation of `nixpkgs.hello`.
-    const HELLO_DRV: &str = r#"Derive([("out","/nix/store/33l4p0pn0mybmqzaxfkpppyh7vx1c74p-hello-2.12.1","","")],[("/nix/store/6z1jfnqqgyqr221zgbpm30v91yfj3r45-bash-5.1-p16.drv",["out"]),("/nix/store/ap9g09fxbicj836zm88d56dn3ff4clxl-stdenv-linux.drv",["out"]),("/nix/store/pf80kikyxr63wrw56k00i1kw6ba76qik-hello-2.12.1.tar.gz.drv",["out"])],["/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],"x86_64-linux","/nix/store/4xw8n979xpivdc46a9ndcvyhwgif00hz-bash-5.1-p16/bin/bash",["-e","/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],[("buildInputs",""),("builder","/nix/store/4xw8n979xpivdc46a9ndcvyhwgif00hz-bash-5.1-p16/bin/bash"),("cmakeFlags",""),("configureFlags",""),("depsBuildBuild",""),("depsBuildBuildPropagated",""),("depsBuildTarget",""),("depsBuildTargetPropagated",""),("depsHostHost",""),("depsHostHostPropagated",""),("depsTargetTarget",""),("depsTargetTargetPropagated",""),("doCheck","1"),("doInstallCheck",""),("mesonFlags",""),("name","hello-2.12.1"),("nativeBuildInputs",""),("out","/nix/store/33l4p0pn0mybmqzaxfkpppyh7vx1c74p-hello-2.12.1"),("outputs","out"),("patches",""),("pname","hello"),("propagatedBuildInputs",""),("propagatedNativeBuildInputs",""),("src","/nix/store/pa10z4ngm0g83kx9mssrqzz30s84vq7k-hello-2.12.1.tar.gz"),("stdenv","/nix/store/cp65c8nk29qq5cl1wyy5qyw103cwmax7-stdenv-linux"),("strictDeps",""),("system","x86_64-linux"),("version","2.12.1")])"#;
-
-    #[test]
-    fn test_no_patterns() {
-        let mut scanner: ReferenceScanner<String> = ReferenceScanner::new(vec![]);
-
-        scanner.scan(HELLO_DRV);
-
-        let result = scanner.finalise();
-
-        assert_eq!(result.len(), 0);
-    }
-
-    #[test]
-    fn test_single_match() {
-        let mut scanner = ReferenceScanner::new(vec![
-            "/nix/store/4xw8n979xpivdc46a9ndcvyhwgif00hz-bash-5.1-p16".to_string(),
-        ]);
-        scanner.scan(HELLO_DRV);
-
-        let result = scanner.finalise();
-
-        assert_eq!(result.len(), 1);
-        assert!(result.contains("/nix/store/4xw8n979xpivdc46a9ndcvyhwgif00hz-bash-5.1-p16"));
-    }
-
-    #[test]
-    fn test_multiple_matches() {
-        let candidates = vec![
-            // these exist in the drv:
-            "/nix/store/33l4p0pn0mybmqzaxfkpppyh7vx1c74p-hello-2.12.1".to_string(),
-            "/nix/store/pf80kikyxr63wrw56k00i1kw6ba76qik-hello-2.12.1.tar.gz.drv".to_string(),
-            "/nix/store/cp65c8nk29qq5cl1wyy5qyw103cwmax7-stdenv-linux".to_string(),
-            // this doesn't:
-            "/nix/store/fn7zvafq26f0c8b17brs7s95s10ibfzs-emacs-28.2.drv".to_string(),
-        ];
-
-        let mut scanner = ReferenceScanner::new(candidates.clone());
-        scanner.scan(HELLO_DRV);
-
-        let result = scanner.finalise();
-        assert_eq!(result.len(), 3);
-
-        for c in candidates[..3].iter() {
-            assert!(result.contains(c));
-        }
-    }
-}
diff --git a/tvix/glue/src/tests/dummy/.keep b/tvix/glue/src/tests/dummy/.keep
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tvix/glue/src/tests/dummy/.keep
diff --git a/tvix/glue/src/tests/mod.rs b/tvix/glue/src/tests/mod.rs
index 5b474be73657..dbde42064a77 100644
--- a/tvix/glue/src/tests/mod.rs
+++ b/tvix/glue/src/tests/mod.rs
@@ -1,10 +1,11 @@
 use std::{rc::Rc, sync::Arc};
 
+use clap::Parser;
 use pretty_assertions::assert_eq;
 use std::path::PathBuf;
 use tvix_build::buildservice::DummyBuildService;
-use tvix_eval::{EvalIO, Value};
-use tvix_store::utils::construct_services;
+use tvix_eval::{EvalIO, EvalMode, Value};
+use tvix_store::utils::{construct_services, ServiceUrlsMemory};
 
 use rstest::rstest;
 
@@ -35,28 +36,32 @@ fn eval_test(code_path: PathBuf, expect_success: bool) {
     let tokio_runtime = tokio::runtime::Runtime::new().unwrap();
     let (blob_service, directory_service, path_info_service, nar_calculation_service) =
         tokio_runtime
-            .block_on(async { construct_services("memory://", "memory://", "memory://").await })
+            .block_on(async {
+                construct_services(ServiceUrlsMemory::parse_from(std::iter::empty::<&str>())).await
+            })
             .unwrap();
 
     let tvix_store_io = Rc::new(TvixStoreIO::new(
         blob_service,
         directory_service,
-        path_info_service.into(),
+        path_info_service,
         nar_calculation_service.into(),
         Arc::new(DummyBuildService::default()),
         tokio_runtime.handle().clone(),
     ));
     // Wrap with TvixIO, so <nix/fetchurl.nix can be imported.
-    let mut eval = tvix_eval::Evaluation::new(
-        Box::new(TvixIO::new(tvix_store_io.clone() as Rc<dyn EvalIO>)) as Box<dyn EvalIO>,
-        true,
-    );
-
-    eval.strict = true;
-    add_derivation_builtins(&mut eval, tvix_store_io.clone());
-    add_fetcher_builtins(&mut eval, tvix_store_io.clone());
-    add_import_builtins(&mut eval, tvix_store_io.clone());
-    configure_nix_path(&mut eval, &None);
+    let mut eval_builder = tvix_eval::Evaluation::builder(Box::new(TvixIO::new(
+        tvix_store_io.clone() as Rc<dyn EvalIO>,
+    )) as Box<dyn EvalIO>)
+    .enable_import()
+    .mode(EvalMode::Strict);
+
+    eval_builder = add_derivation_builtins(eval_builder, Rc::clone(&tvix_store_io));
+    eval_builder = add_fetcher_builtins(eval_builder, Rc::clone(&tvix_store_io));
+    eval_builder = add_import_builtins(eval_builder, tvix_store_io);
+    eval_builder = configure_nix_path(eval_builder, &None);
+
+    let eval = eval_builder.build();
 
     let result = eval.evaluate(code, Some(code_path.clone()));
     let failed = match result.value {
diff --git a/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.exp b/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.exp
index a136b0035e0a..e27068dac1be 100644
--- a/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.exp
+++ b/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.exp
@@ -1 +1 @@
-[ true true true true true true true true true true true true true ]
+[ true true true true true true true true true true true true true true ]
diff --git a/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.nix b/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.nix
index e5719e00c3ae..3fe8b4cbbd51 100644
--- a/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.nix
+++ b/tvix/glue/src/tests/tvix_tests/eval-okay-context-introspection.nix
@@ -80,4 +80,5 @@ in
   # `toJSON` tests
   (builtins.hasContext (builtins.toJSON an-str))
   (builtins.hasContext (builtins.toJSON an-list))
+  (builtins.hasContext (builtins.toJSON { __toString = _: "${drv}"; }))
 ]
diff --git a/tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.exp b/tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.exp
new file mode 100644
index 000000000000..26a467d2799d
--- /dev/null
+++ b/tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.exp
@@ -0,0 +1 @@
+{ plain = "/nix/store/vqsvbisgiqrqa1y0qljigq4ds5h38gym-dummy"; withSubPath = "/nix/store/vqsvbisgiqrqa1y0qljigq4ds5h38gym-dummy/.keep"; }
diff --git a/tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.nix b/tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.nix
new file mode 100644
index 000000000000..2d1fc45871f3
--- /dev/null
+++ b/tvix/glue/src/tests/tvix_tests/eval-okay-storePath2.nix
@@ -0,0 +1,8 @@
+let
+  path = builtins.unsafeDiscardStringContext "${../dummy}";
+  storePath = builtins.storePath path;
+in
+{
+  plain = builtins.storePath path;
+  withSubPath = builtins.storePath (path + "/.keep");
+}
diff --git a/tvix/glue/src/tests/tvix_tests/eval-okay-toxml-context.nix b/tvix/glue/src/tests/tvix_tests/eval-okay-toxml-context.nix
index 933aa46022dd..352470980383 100644
--- a/tvix/glue/src/tests/tvix_tests/eval-okay-toxml-context.nix
+++ b/tvix/glue/src/tests/tvix_tests/eval-okay-toxml-context.nix
@@ -4,7 +4,7 @@
     inherit (derivation {
       name = "test";
       builder = "/bin/sh";
-      system = builtins.currentSystem;
+      system = "x86_64-linux";
     }) drvPath;
   }))
 
diff --git a/tvix/glue/src/tvix_build.rs b/tvix/glue/src/tvix_build.rs
index e9eb1725ef3e..fa73224992e6 100644
--- a/tvix/glue/src/tvix_build.rs
+++ b/tvix/glue/src/tvix_build.rs
@@ -1,16 +1,14 @@
 //! This module contains glue code translating from
-//! [nix_compat::derivation::Derivation] to [tvix_build::proto::BuildRequest].
+//! [nix_compat::derivation::Derivation] to [tvix_build::buildservice::BuildRequest].
 
-use std::collections::{BTreeMap, BTreeSet};
+use std::collections::{BTreeMap, HashSet};
+use std::path::PathBuf;
 
 use bytes::Bytes;
-use nix_compat::{derivation::Derivation, nixbase32};
+use nix_compat::{derivation::Derivation, nixbase32, store_path::StorePath};
 use sha2::{Digest, Sha256};
-use tvix_build::proto::{
-    build_request::{AdditionalFile, BuildConstraints, EnvVar},
-    BuildRequest,
-};
-use tvix_castore::proto::{self, node::Node};
+use tvix_build::buildservice::{AdditionalFile, BuildConstraints, BuildRequest, EnvVar};
+use tvix_castore::Node;
 
 /// These are the environment variables that Nix sets in its sandbox for every
 /// build.
@@ -29,17 +27,30 @@ const NIX_ENVIRONMENT_VARS: [(&str, &str); 12] = [
     ("TMPDIR", "/build"),
 ];
 
-/// Takes a [Derivation] and turns it into a [BuildRequest].
+/// Get an iterator of store paths whose nixbase32 hashes will be the needles for refscanning
+/// Importantly, the returned order will match the one used by [derivation_to_build_request]
+/// so users may use this function to map back from the found needles to a store path
+pub(crate) fn get_refscan_needles(
+    derivation: &Derivation,
+) -> impl Iterator<Item = &StorePath<String>> {
+    derivation
+        .outputs
+        .values()
+        .filter_map(|output| output.path.as_ref())
+        .chain(derivation.input_sources.iter())
+        .chain(derivation.input_derivations.keys())
+}
+
+/// Takes a [Derivation] and turns it into a [buildservice::BuildRequest].
 /// It assumes the Derivation has been validated.
 /// It needs two lookup functions:
 /// - one translating input sources to a castore node
 ///   (`fn_input_sources_to_node`)
 /// - one translating a tuple of drv path and (a subset of their) output names to
 ///   castore nodes of the selected outpus (`fn_input_drvs_to_output_nodes`).
-#[allow(clippy::mutable_key_type)]
 pub(crate) fn derivation_to_build_request(
     derivation: &Derivation,
-    inputs: BTreeSet<Node>,
+    inputs: BTreeMap<StorePath<String>, Node>,
 ) -> std::io::Result<BuildRequest> {
     debug_assert!(derivation.validate(true).is_ok(), "drv must validate");
 
@@ -48,16 +59,6 @@ pub(crate) fn derivation_to_build_request(
     command_args.push(derivation.builder.clone());
     command_args.extend_from_slice(&derivation.arguments);
 
-    // produce output_paths, which is the absolute path of each output (sorted)
-    let mut output_paths: Vec<String> = derivation
-        .outputs
-        .values()
-        .map(|e| e.path_str()[1..].to_owned())
-        .collect();
-
-    // Sort the outputs. We can use sort_unstable, as these are unique strings.
-    output_paths.sort_unstable();
-
     // Produce environment_vars and additional files.
     // We use a BTreeMap while producing, and only realize the resulting Vec
     // while populating BuildRequest, so we don't need to worry about ordering.
@@ -86,23 +87,41 @@ pub(crate) fn derivation_to_build_request(
     // TODO: handle __json (structured attrs, provide JSON file and source-able bash script)
 
     // Produce constraints.
-    let constraints = Some(BuildConstraints {
-        system: derivation.system.clone(),
-        min_memory: 0,
-        available_ro_paths: vec![],
-        // in case this is a fixed-output derivation, allow network access.
-        network_access: derivation.outputs.len() == 1
-            && derivation
-                .outputs
-                .get("out")
-                .expect("invalid derivation")
-                .is_fixed(),
-        provide_bin_sh: true,
-    });
+    let mut constraints = HashSet::from([
+        BuildConstraints::System(derivation.system.clone()),
+        BuildConstraints::ProvideBinSh,
+    ]);
+
+    if derivation.outputs.len() == 1
+        && derivation
+            .outputs
+            .get("out")
+            .expect("Tvix bug: Derivation has no out output")
+            .is_fixed()
+    {
+        constraints.insert(BuildConstraints::NetworkAccess);
+    }
 
-    let build_request = BuildRequest {
+    Ok(BuildRequest {
+        // Importantly, this must match the order of get_refscan_needles, since users may use that
+        // function to map back from the found needles to a store path
+        refscan_needles: get_refscan_needles(derivation)
+            .map(|path| nixbase32::encode(path.digest()))
+            .collect(),
         command_args,
-        outputs: output_paths,
+
+        outputs: {
+            // produce output_paths, which is the absolute path of each output (sorted)
+            let mut output_paths: Vec<PathBuf> = derivation
+                .outputs
+                .values()
+                .map(|e| PathBuf::from(e.path_str()[1..].to_owned()))
+                .collect();
+
+            // Sort the outputs. We can use sort_unstable, as these are unique strings.
+            output_paths.sort_unstable();
+            output_paths
+        },
 
         // Turn this into a sorted-by-key Vec<EnvVar>.
         environment_vars: environment_vars
@@ -111,7 +130,15 @@ pub(crate) fn derivation_to_build_request(
             .collect(),
         inputs: inputs
             .into_iter()
-            .map(|n| proto::Node { node: Some(n) })
+            .map(|(path, node)| {
+                (
+                    path.to_string()
+                        .as_str()
+                        .try_into()
+                        .expect("Tvix bug: unable to convert store path basename to PathComponent"),
+                    node,
+                )
+            })
             .collect(),
         inputs_dir: nix_compat::store_path::STORE_DIR[1..].into(),
         constraints,
@@ -119,17 +146,12 @@ pub(crate) fn derivation_to_build_request(
         scratch_paths: vec!["build".into(), "nix/store".into()],
         additional_files: additional_files
             .into_iter()
-            .map(|(path, contents)| AdditionalFile { path, contents })
+            .map(|(path, contents)| AdditionalFile {
+                path: PathBuf::from(path),
+                contents,
+            })
             .collect(),
-    };
-
-    debug_assert!(
-        build_request.validate().is_ok(),
-        "invalid BuildRequest: {}",
-        build_request.validate().unwrap_err()
-    );
-
-    Ok(build_request)
+    })
 }
 
 /// handle passAsFile, if set.
@@ -192,31 +214,26 @@ fn calculate_pass_as_file_env(k: &str) -> (String, String) {
 
 #[cfg(test)]
 mod test {
-    use std::collections::BTreeSet;
-
     use bytes::Bytes;
-    use nix_compat::derivation::Derivation;
-    use tvix_build::proto::{
-        build_request::{AdditionalFile, BuildConstraints, EnvVar},
-        BuildRequest,
-    };
-    use tvix_castore::{
-        fixtures::DUMMY_DIGEST,
-        proto::{self, node::Node, DirectoryNode},
-    };
+    use nix_compat::{derivation::Derivation, store_path::StorePath};
+    use std::collections::{BTreeMap, HashSet};
+    use std::sync::LazyLock;
+    use tvix_castore::fixtures::DUMMY_DIGEST;
+    use tvix_castore::{Node, PathComponent};
+
+    use tvix_build::buildservice::{AdditionalFile, BuildConstraints, BuildRequest, EnvVar};
 
     use crate::tvix_build::NIX_ENVIRONMENT_VARS;
 
     use super::derivation_to_build_request;
-    use lazy_static::lazy_static;
-
-    lazy_static! {
-        static ref INPUT_NODE_FOO: Node = Node::Directory(DirectoryNode {
-            name: Bytes::from("mp57d33657rf34lzvlbpfa1gjfv5gmpg-bar"),
-            digest: DUMMY_DIGEST.clone().into(),
-            size: 42,
-        });
-    }
+
+    static INPUT_NODE_FOO_NAME: LazyLock<Bytes> =
+        LazyLock::new(|| "mp57d33657rf34lzvlbpfa1gjfv5gmpg-bar".into());
+
+    static INPUT_NODE_FOO: LazyLock<Node> = LazyLock::new(|| Node::Directory {
+        digest: DUMMY_DIGEST.clone(),
+        size: 42,
+    });
 
     #[test]
     fn test_derivation_to_build_request() {
@@ -224,9 +241,14 @@ mod test {
 
         let derivation = Derivation::from_aterm_bytes(aterm_bytes).expect("must parse");
 
-        let build_request =
-            derivation_to_build_request(&derivation, BTreeSet::from([INPUT_NODE_FOO.clone()]))
-                .expect("must succeed");
+        let build_request = derivation_to_build_request(
+            &derivation,
+            BTreeMap::from([(
+                StorePath::<String>::from_bytes(&INPUT_NODE_FOO_NAME.clone()).unwrap(),
+                INPUT_NODE_FOO.clone(),
+            )]),
+        )
+        .expect("must succeed");
 
         let mut expected_environment_vars = vec![
             EnvVar {
@@ -263,20 +285,22 @@ mod test {
                 command_args: vec![":".into()],
                 outputs: vec!["nix/store/fhaj6gmwns62s6ypkcldbaj2ybvkhx3p-foo".into()],
                 environment_vars: expected_environment_vars,
-                inputs: vec![proto::Node {
-                    node: Some(INPUT_NODE_FOO.clone())
-                }],
+                inputs: BTreeMap::from([(
+                    PathComponent::try_from(INPUT_NODE_FOO_NAME.clone()).unwrap(),
+                    INPUT_NODE_FOO.clone()
+                )]),
                 inputs_dir: "nix/store".into(),
-                constraints: Some(BuildConstraints {
-                    system: derivation.system.clone(),
-                    min_memory: 0,
-                    network_access: false,
-                    available_ro_paths: vec![],
-                    provide_bin_sh: true,
-                }),
+                constraints: HashSet::from([
+                    BuildConstraints::System(derivation.system.clone()),
+                    BuildConstraints::ProvideBinSh
+                ]),
                 additional_files: vec![],
                 working_dir: "build".into(),
                 scratch_paths: vec!["build".into(), "nix/store".into()],
+                refscan_needles: vec![
+                    "fhaj6gmwns62s6ypkcldbaj2ybvkhx3p".into(),
+                    "ss2p4wmxijn652haqyd7dckxwl4c7hxx".into()
+                ],
             },
             build_request
         );
@@ -289,7 +313,7 @@ mod test {
         let derivation = Derivation::from_aterm_bytes(aterm_bytes).expect("must parse");
 
         let build_request =
-            derivation_to_build_request(&derivation, BTreeSet::from([])).expect("must succeed");
+            derivation_to_build_request(&derivation, BTreeMap::from([])).expect("must succeed");
 
         let mut expected_environment_vars = vec![
             EnvVar {
@@ -334,18 +358,17 @@ mod test {
                 command_args: vec![":".to_string()],
                 outputs: vec!["nix/store/4q0pg5zpfmznxscq3avycvf9xdvx50n3-bar".into()],
                 environment_vars: expected_environment_vars,
-                inputs: vec![],
+                inputs: BTreeMap::new(),
                 inputs_dir: "nix/store".into(),
-                constraints: Some(BuildConstraints {
-                    system: derivation.system.clone(),
-                    min_memory: 0,
-                    network_access: true,
-                    available_ro_paths: vec![],
-                    provide_bin_sh: true,
-                }),
+                constraints: HashSet::from([
+                    BuildConstraints::System(derivation.system.clone()),
+                    BuildConstraints::NetworkAccess,
+                    BuildConstraints::ProvideBinSh
+                ]),
                 additional_files: vec![],
                 working_dir: "build".into(),
                 scratch_paths: vec!["build".into(), "nix/store".into()],
+                refscan_needles: vec!["4q0pg5zpfmznxscq3avycvf9xdvx50n3".into()],
             },
             build_request
         );
@@ -359,7 +382,7 @@ mod test {
         let derivation = Derivation::from_aterm_bytes(aterm_bytes).expect("must parse");
 
         let build_request =
-            derivation_to_build_request(&derivation, BTreeSet::from([])).expect("must succeed");
+            derivation_to_build_request(&derivation, BTreeMap::from([])).expect("must succeed");
 
         let mut expected_environment_vars = vec![
             // Note how bar and baz are not present in the env anymore,
@@ -407,15 +430,12 @@ mod test {
                 command_args: vec![":".to_string()],
                 outputs: vec!["nix/store/pp17lwra2jkx8rha15qabg2q3wij72lj-foo".into()],
                 environment_vars: expected_environment_vars,
-                inputs: vec![],
+                inputs: BTreeMap::new(),
                 inputs_dir: "nix/store".into(),
-                constraints: Some(BuildConstraints {
-                    system: derivation.system.clone(),
-                    min_memory: 0,
-                    network_access: false,
-                    available_ro_paths: vec![],
-                    provide_bin_sh: true,
-                }),
+                constraints: HashSet::from([
+                    BuildConstraints::System(derivation.system.clone()),
+                    BuildConstraints::ProvideBinSh,
+                ]),
                 additional_files: vec![
                     // baz env
                     AdditionalFile {
@@ -432,6 +452,7 @@ mod test {
                 ],
                 working_dir: "build".into(),
                 scratch_paths: vec!["build".into(), "nix/store".into()],
+                refscan_needles: vec!["pp17lwra2jkx8rha15qabg2q3wij72lj".into()],
             },
             build_request
         );
diff --git a/tvix/glue/src/tvix_io.rs b/tvix/glue/src/tvix_io.rs
index db0c2cef77aa..323fa8d20ccb 100644
--- a/tvix/glue/src/tvix_io.rs
+++ b/tvix/glue/src/tvix_io.rs
@@ -1,12 +1,10 @@
 //! This module implements a wrapper around tvix-eval's [EvalIO] type,
 //! adding functionality which is required by tvix-cli:
 //!
-//! 1. Marking plain paths known to the reference scanner.
-//! 2. Handling the C++ Nix `__corepkgs__`-hack for nixpkgs bootstrapping.
+//! 1. Handling the C++ Nix `__corepkgs__`-hack for nixpkgs bootstrapping.
 //!
 //! All uses of [EvalIO] in tvix-cli must make use of this wrapper,
-//! otherwise fundamental features like nixpkgs bootstrapping and hash
-//! calculation will not work.
+//! otherwise nixpkgs bootstrapping will not work.
 
 use std::io::{self, Cursor};
 use std::path::{Path, PathBuf};
diff --git a/tvix/glue/src/tvix_store_io.rs b/tvix/glue/src/tvix_store_io.rs
index 4e5488067f8f..67a88e13c54b 100644
--- a/tvix/glue/src/tvix_store_io.rs
+++ b/tvix/glue/src/tvix_store_io.rs
@@ -1,12 +1,9 @@
 //! This module provides an implementation of EvalIO talking to tvix-store.
-use bytes::Bytes;
 use futures::{StreamExt, TryStreamExt};
-use nix_compat::nixhash::NixHash;
-use nix_compat::store_path::StorePathRef;
 use nix_compat::{nixhash::CAHash, store_path::StorePath};
+use std::collections::BTreeMap;
 use std::{
     cell::RefCell,
-    collections::BTreeSet,
     io,
     path::{Path, PathBuf},
     sync::Arc,
@@ -15,17 +12,15 @@ use tokio_util::io::SyncIoBridge;
 use tracing::{error, instrument, warn, Level, Span};
 use tracing_indicatif::span_ext::IndicatifSpanExt;
 use tvix_build::buildservice::BuildService;
-use tvix_castore::proto::node::Node;
 use tvix_eval::{EvalIO, FileType, StdIO};
 use tvix_store::nar::NarCalculationService;
 
 use tvix_castore::{
     blobservice::BlobService,
     directoryservice::{self, DirectoryService},
-    proto::NamedNode,
-    B3Digest,
+    Node,
 };
-use tvix_store::{pathinfoservice::PathInfoService, proto::PathInfo};
+use tvix_store::pathinfoservice::{PathInfo, PathInfoService};
 
 use crate::fetchers::Fetcher;
 use crate::known_paths::KnownPaths;
@@ -67,7 +62,7 @@ pub struct TvixStoreIO {
     >,
 
     // Paths known how to produce, by building or fetching.
-    pub(crate) known_paths: RefCell<KnownPaths>,
+    pub known_paths: RefCell<KnownPaths>,
 }
 
 impl TvixStoreIO {
@@ -104,10 +99,10 @@ impl TvixStoreIO {
     ///
     /// In case there is no PathInfo yet, this means we need to build it
     /// (which currently is stubbed out still).
-    #[instrument(skip(self, store_path), fields(store_path=%store_path, indicatif.pb_show=1), ret(level = Level::TRACE), err)]
+    #[instrument(skip(self, store_path), fields(store_path=%store_path, indicatif.pb_show=1), ret(level = Level::TRACE), err(level = Level::TRACE))]
     async fn store_path_to_node(
         &self,
-        store_path: &StorePath,
+        store_path: &StorePath<String>,
         sub_path: &Path,
     ) -> io::Result<Option<Node>> {
         // Find the root node for the store_path.
@@ -121,8 +116,8 @@ impl TvixStoreIO {
             .get(*store_path.digest())
             .await?
         {
-            // if we have a PathInfo, we know there will be a root_node (due to validation)
-            Some(path_info) => path_info.node.expect("no node").node.expect("no node"),
+            // TODO: use stricter typed BuildRequest here.
+            Some(path_info) => path_info.node,
             // If there's no PathInfo found, this normally means we have to
             // trigger the build (and insert into PathInfoService, after
             // reference scanning).
@@ -185,8 +180,7 @@ impl TvixStoreIO {
                         // derivation_to_build_request needs castore nodes for all inputs.
                         // Provide them, which means, here is where we recursively build
                         // all dependencies.
-                        #[allow(clippy::mutable_key_type)]
-                        let mut input_nodes: BTreeSet<Node> =
+                        let mut inputs: BTreeMap<StorePath<String>, Node> =
                             futures::stream::iter(drv.input_derivations.iter())
                                 .map(|(input_drv_path, output_names)| {
                                     // look up the derivation object
@@ -201,7 +195,7 @@ impl TvixStoreIO {
                                     };
 
                                     // convert output names to actual paths
-                                    let output_paths: Vec<StorePath> = output_names
+                                    let output_paths: Vec<StorePath<String>> = output_names
                                         .iter()
                                         .map(|output_name| {
                                             input_drv
@@ -214,6 +208,7 @@ impl TvixStoreIO {
                                                 .clone()
                                         })
                                         .collect();
+
                                     // For each output, ask for the castore node.
                                     // We're in a per-derivation context, so if they're
                                     // not built yet they'll all get built together.
@@ -228,7 +223,7 @@ impl TvixStoreIO {
                                                 .await?;
 
                                             if let Some(node) = node {
-                                                Ok(node)
+                                                Ok((output_path, node))
                                             } else {
                                                 Err(io::Error::other("no node produced"))
                                             }
@@ -242,26 +237,29 @@ impl TvixStoreIO {
                                 .try_collect()
                                 .await?;
 
-                        // add input sources
                         // FUTUREWORK: merge these who things together
-                        #[allow(clippy::mutable_key_type)]
-                        let input_nodes_input_sources: BTreeSet<Node> =
+                        // add input sources
+                        let input_sources: BTreeMap<_, _> =
                             futures::stream::iter(drv.input_sources.iter())
                                 .then(|input_source| {
-                                    Box::pin(async {
-                                        let node = self
-                                            .store_path_to_node(input_source, Path::new(""))
-                                            .await?;
-                                        if let Some(node) = node {
-                                            Ok(node)
-                                        } else {
-                                            Err(io::Error::other("no node produced"))
+                                    Box::pin({
+                                        let input_source = input_source.clone();
+                                        async move {
+                                            let node = self
+                                                .store_path_to_node(&input_source, Path::new(""))
+                                                .await?;
+                                            if let Some(node) = node {
+                                                Ok((input_source, node))
+                                            } else {
+                                                Err(io::Error::other("no node produced"))
+                                            }
                                         }
                                     })
                                 })
                                 .try_collect()
                                 .await?;
-                        input_nodes.extend(input_nodes_input_sources);
+
+                        inputs.extend(input_sources);
 
                         span.pb_set_message(&format!("🔨Building {}", &store_path));
 
@@ -270,7 +268,7 @@ impl TvixStoreIO {
                         // operations, so dealt with in the Some(…) match arm
 
                         // synthesize the build request.
-                        let build_request = derivation_to_build_request(&drv, input_nodes)?;
+                        let build_request = derivation_to_build_request(&drv, inputs)?;
 
                         // create a build
                         let build_result = self
@@ -280,45 +278,77 @@ impl TvixStoreIO {
                             .await
                             .map_err(|e| std::io::Error::new(io::ErrorKind::Other, e))?;
 
-                        // TODO: refscan
+                        // Maps from the index in refscan_needles to the full store path
+                        // Used to map back to the actual store path from the found needles
+                        // Importantly, this must match the order of the needles generated in derivation_to_build_request
+                        let refscan_needles =
+                            crate::tvix_build::get_refscan_needles(&drv).collect::<Vec<_>>();
 
                         // For each output, insert a PathInfo.
-                        for output in &build_result.outputs {
-                            let root_node = output.node.as_ref().expect("invalid root node");
+                        for ((output, output_needles), drv_output) in build_result
+                            .outputs
+                            .iter()
+                            .zip(build_result.outputs_needles.iter())
+                            .zip(drv.outputs.iter())
+                        {
+                            let output_node = output
+                                .clone()
+                                .try_into_anonymous_node()
+                                .expect("invalid node");
+
+                            let output_needles: Vec<_> = output_needles
+                                .needles
+                                .iter()
+                                // Map each output needle index back to the refscan_needle
+                                .map(|idx| {
+                                    refscan_needles
+                                        .get(*idx as usize)
+                                        .ok_or(std::io::Error::new(
+                                            std::io::ErrorKind::Other,
+                                            "invalid build response",
+                                        ))
+                                })
+                                .collect::<Result<_, std::io::Error>>()?;
 
                             // calculate the nar representation
                             let (nar_size, nar_sha256) = self
                                 .nar_calculation_service
-                                .calculate_nar(root_node)
+                                .calculate_nar(&output_node)
                                 .await?;
 
                             // assemble the PathInfo to persist
                             let path_info = PathInfo {
-                                node: Some(tvix_castore::proto::Node {
-                                    node: Some(root_node.clone()),
-                                }),
-                                references: vec![], // TODO: refscan
-                                narinfo: Some(tvix_store::proto::NarInfo {
-                                    nar_size,
-                                    nar_sha256: Bytes::from(nar_sha256.to_vec()),
-                                    signatures: vec![],
-                                    reference_names: vec![], // TODO: refscan
-                                    deriver: Some(tvix_store::proto::StorePath {
-                                        name: drv_path
+                                store_path: drv_output
+                                    .1
+                                    .path
+                                    .as_ref()
+                                    .ok_or(std::io::Error::new(
+                                        std::io::ErrorKind::Other,
+                                        "Tvix bug: missing output store path",
+                                    ))?
+                                    .to_owned(),
+                                node: output_node,
+                                references: output_needles
+                                    .iter()
+                                    .map(|s| (**s).to_owned())
+                                    .collect(),
+                                nar_size,
+                                nar_sha256,
+                                signatures: vec![],
+                                deriver: Some(
+                                    StorePath::from_name_and_digest_fixed(
+                                        drv_path
                                             .name()
                                             .strip_suffix(".drv")
-                                            .expect("missing .drv suffix")
-                                            .to_string(),
-                                        digest: drv_path.digest().to_vec().into(),
-                                    }),
-                                    ca: drv.fod_digest().map(
-                                        |fod_digest| -> tvix_store::proto::nar_info::Ca {
-                                            (&CAHash::Nar(nix_compat::nixhash::NixHash::Sha256(
-                                                fod_digest,
-                                            )))
-                                                .into()
-                                        },
+                                            .expect("missing .drv suffix"),
+                                        *drv_path.digest(),
+                                    )
+                                    .expect(
+                                        "Tvix bug: StorePath without .drv suffix must be valid",
                                     ),
+                                ),
+                                ca: drv.fod_digest().map(|fod_digest| {
+                                    CAHash::Nar(nix_compat::nixhash::NixHash::Sha256(fod_digest))
                                 }),
                             };
 
@@ -329,16 +359,17 @@ impl TvixStoreIO {
                         }
 
                         // find the output for the store path requested
+                        let s = store_path.to_string();
+
                         build_result
                             .outputs
                             .into_iter()
-                            .find(|output_node| {
-                                output_node.node.as_ref().expect("invalid node").get_name()
-                                    == store_path.to_string().as_bytes()
+                            .map(|e| e.try_into_name_and_node().expect("invalid node"))
+                            .find(|(output_name, _output_node)| {
+                                output_name.as_ref() == s.as_bytes()
                             })
                             .expect("build didn't produce the store path")
-                            .node
-                            .expect("invalid node")
+                            .1
                     }
                 }
             }
@@ -352,81 +383,15 @@ impl TvixStoreIO {
             .await
             .map_err(|e| std::io::Error::new(io::ErrorKind::Other, e))
     }
-
-    pub(crate) async fn node_to_path_info(
-        &self,
-        name: &str,
-        path: &Path,
-        ca: &CAHash,
-        root_node: Node,
-    ) -> io::Result<(PathInfo, NixHash, StorePath)> {
-        // Ask the PathInfoService for the NAR size and sha256
-        // We always need it no matter what is the actual hash mode
-        // because the path info construct a narinfo which *always*
-        // require a SHA256 of the NAR representation and the NAR size.
-        let (nar_size, nar_sha256) = self
-            .nar_calculation_service
-            .as_ref()
-            .calculate_nar(&root_node)
-            .await?;
-
-        // Calculate the output path. This might still fail, as some names are illegal.
-        let output_path =
-            nix_compat::store_path::build_ca_path(name, ca, Vec::<String>::new(), false).map_err(
-                |_| {
-                    std::io::Error::new(
-                        std::io::ErrorKind::InvalidData,
-                        format!("invalid name: {}", name),
-                    )
-                },
-            )?;
-
-        // assemble a new root_node with a name that is derived from the nar hash.
-        let root_node = root_node.rename(output_path.to_string().into_bytes().into());
-        tvix_store::import::log_node(&root_node, path);
-
-        let path_info =
-            tvix_store::import::derive_nar_ca_path_info(nar_size, nar_sha256, Some(ca), root_node);
-
-        Ok((
-            path_info,
-            NixHash::Sha256(nar_sha256),
-            output_path.to_owned(),
-        ))
-    }
-
-    pub(crate) async fn register_node_in_path_info_service(
-        &self,
-        name: &str,
-        path: &Path,
-        ca: &CAHash,
-        root_node: Node,
-    ) -> io::Result<StorePath> {
-        let (path_info, _, output_path) = self.node_to_path_info(name, path, ca, root_node).await?;
-        let _path_info = self.path_info_service.as_ref().put(path_info).await?;
-
-        Ok(output_path)
-    }
-
-    pub async fn store_path_exists<'a>(&'a self, store_path: StorePathRef<'a>) -> io::Result<bool> {
-        Ok(self
-            .path_info_service
-            .as_ref()
-            .get(*store_path.digest())
-            .await?
-            .is_some())
-    }
 }
 
 impl EvalIO for TvixStoreIO {
     #[instrument(skip(self), ret(level = Level::TRACE), err)]
     fn path_exists(&self, path: &Path) -> io::Result<bool> {
-        if let Ok((store_path, sub_path)) =
-            StorePath::from_absolute_path_full(&path.to_string_lossy())
-        {
+        if let Ok((store_path, sub_path)) = StorePath::from_absolute_path_full(path) {
             if self
                 .tokio_handle
-                .block_on(self.store_path_to_node(&store_path, &sub_path))?
+                .block_on(self.store_path_to_node(&store_path, sub_path))?
                 .is_some()
             {
                 Ok(true)
@@ -443,35 +408,21 @@ impl EvalIO for TvixStoreIO {
 
     #[instrument(skip(self), err)]
     fn open(&self, path: &Path) -> io::Result<Box<dyn io::Read>> {
-        if let Ok((store_path, sub_path)) =
-            StorePath::from_absolute_path_full(&path.to_string_lossy())
-        {
+        if let Ok((store_path, sub_path)) = StorePath::from_absolute_path_full(path) {
             if let Some(node) = self
                 .tokio_handle
-                .block_on(async { self.store_path_to_node(&store_path, &sub_path).await })?
+                .block_on(async { self.store_path_to_node(&store_path, sub_path).await })?
             {
                 // depending on the node type, treat open differently
                 match node {
-                    Node::Directory(_) => {
+                    Node::Directory { .. } => {
                         // This would normally be a io::ErrorKind::IsADirectory (still unstable)
                         Err(io::Error::new(
                             io::ErrorKind::Unsupported,
                             format!("tried to open directory at {:?}", path),
                         ))
                     }
-                    Node::File(file_node) => {
-                        let digest: B3Digest =
-                            file_node.digest.clone().try_into().map_err(|_e| {
-                                error!(
-                                    file_node = ?file_node,
-                                    "invalid digest"
-                                );
-                                io::Error::new(
-                                    io::ErrorKind::InvalidData,
-                                    format!("invalid digest length in file node: {:?}", file_node),
-                                )
-                            })?;
-
+                    Node::File { digest, .. } => {
                         self.tokio_handle.block_on(async {
                             let resp = self.blob_service.as_ref().open_read(&digest).await?;
                             match resp {
@@ -493,7 +444,7 @@ impl EvalIO for TvixStoreIO {
                             }
                         })
                     }
-                    Node::Symlink(_symlink_node) => Err(io::Error::new(
+                    Node::Symlink { .. } => Err(io::Error::new(
                         io::ErrorKind::Unsupported,
                         "open for symlinks is unsupported",
                     ))?,
@@ -511,17 +462,15 @@ impl EvalIO for TvixStoreIO {
 
     #[instrument(skip(self), ret(level = Level::TRACE), err)]
     fn file_type(&self, path: &Path) -> io::Result<FileType> {
-        if let Ok((store_path, sub_path)) =
-            StorePath::from_absolute_path_full(&path.to_string_lossy())
-        {
+        if let Ok((store_path, sub_path)) = StorePath::from_absolute_path_full(path) {
             if let Some(node) = self
                 .tokio_handle
-                .block_on(async { self.store_path_to_node(&store_path, &sub_path).await })?
+                .block_on(async { self.store_path_to_node(&store_path, sub_path).await })?
             {
                 match node {
-                    Node::Directory(_) => Ok(FileType::Directory),
-                    Node::File(_) => Ok(FileType::Regular),
-                    Node::Symlink(_) => Ok(FileType::Symlink),
+                    Node::Directory { .. } => Ok(FileType::Directory),
+                    Node::File { .. } => Ok(FileType::Regular),
+                    Node::Symlink { .. } => Ok(FileType::Symlink),
                 }
             } else {
                 self.std_io.file_type(path)
@@ -533,36 +482,24 @@ impl EvalIO for TvixStoreIO {
 
     #[instrument(skip(self), ret(level = Level::TRACE), err)]
     fn read_dir(&self, path: &Path) -> io::Result<Vec<(bytes::Bytes, FileType)>> {
-        if let Ok((store_path, sub_path)) =
-            StorePath::from_absolute_path_full(&path.to_string_lossy())
-        {
+        if let Ok((store_path, sub_path)) = StorePath::from_absolute_path_full(path) {
             if let Some(node) = self
                 .tokio_handle
-                .block_on(async { self.store_path_to_node(&store_path, &sub_path).await })?
+                .block_on(async { self.store_path_to_node(&store_path, sub_path).await })?
             {
                 match node {
-                    Node::Directory(directory_node) => {
+                    Node::Directory { digest, .. } => {
                         // fetch the Directory itself.
-                        let digest: B3Digest =
-                            directory_node.digest.clone().try_into().map_err(|_e| {
-                                io::Error::new(
-                                    io::ErrorKind::InvalidData,
-                                    format!(
-                                        "invalid digest length in directory node: {:?}",
-                                        directory_node
-                                    ),
-                                )
-                            })?;
-
-                        if let Some(directory) = self.tokio_handle.block_on(async {
-                            self.directory_service.as_ref().get(&digest).await
+                        if let Some(directory) = self.tokio_handle.block_on({
+                            let digest = digest.clone();
+                            async move { self.directory_service.as_ref().get(&digest).await }
                         })? {
                             let mut children: Vec<(bytes::Bytes, FileType)> = Vec::new();
-                            for node in directory.nodes() {
+                            for (name, node) in directory.into_nodes() {
                                 children.push(match node {
-                                    Node::Directory(e) => (e.name, FileType::Directory),
-                                    Node::File(e) => (e.name, FileType::Regular),
-                                    Node::Symlink(e) => (e.name, FileType::Symlink),
+                                    Node::Directory { .. } => (name.into(), FileType::Directory),
+                                    Node::File { .. } => (name.clone().into(), FileType::Regular),
+                                    Node::Symlink { .. } => (name.into(), FileType::Symlink),
                                 })
                             }
                             Ok(children)
@@ -579,14 +516,14 @@ impl EvalIO for TvixStoreIO {
                             ))?
                         }
                     }
-                    Node::File(_file_node) => {
+                    Node::File { .. } => {
                         // This would normally be a io::ErrorKind::NotADirectory (still unstable)
                         Err(io::Error::new(
                             io::ErrorKind::Unsupported,
                             "tried to readdir path {:?}, which is a file",
                         ))?
                     }
-                    Node::Symlink(_symlink_node) => Err(io::Error::new(
+                    Node::Symlink { .. } => Err(io::Error::new(
                         io::ErrorKind::Unsupported,
                         "read_dir for symlinks is unsupported",
                     ))?,
@@ -601,7 +538,7 @@ impl EvalIO for TvixStoreIO {
 
     #[instrument(skip(self), ret(level = Level::TRACE), err)]
     fn import_path(&self, path: &Path) -> io::Result<PathBuf> {
-        let output_path = self.tokio_handle.block_on(async {
+        let path_info = self.tokio_handle.block_on({
             tvix_store::import::import_path_as_nar_ca(
                 path,
                 tvix_store::import::path_to_name(path)?,
@@ -610,10 +547,10 @@ impl EvalIO for TvixStoreIO {
                 &self.path_info_service,
                 &self.nar_calculation_service,
             )
-            .await
         })?;
 
-        Ok(output_path.to_absolute_path().into())
+        // From the returned PathInfo, extract the store path and return it.
+        Ok(path_info.store_path.to_absolute_path().into())
     }
 
     #[instrument(skip(self), ret(level = Level::TRACE))]
@@ -627,10 +564,11 @@ mod tests {
     use std::{path::Path, rc::Rc, sync::Arc};
 
     use bstr::ByteSlice;
+    use clap::Parser;
     use tempfile::TempDir;
     use tvix_build::buildservice::DummyBuildService;
     use tvix_eval::{EvalIO, EvaluationResult};
-    use tvix_store::utils::construct_services;
+    use tvix_store::utils::{construct_services, ServiceUrlsMemory};
 
     use super::TvixStoreIO;
     use crate::builtins::{add_derivation_builtins, add_fetcher_builtins, add_import_builtins};
@@ -642,22 +580,27 @@ mod tests {
         let tokio_runtime = tokio::runtime::Runtime::new().unwrap();
         let (blob_service, directory_service, path_info_service, nar_calculation_service) =
             tokio_runtime
-                .block_on(async { construct_services("memory://", "memory://", "memory://").await })
+                .block_on(async {
+                    construct_services(ServiceUrlsMemory::parse_from(std::iter::empty::<&str>()))
+                        .await
+                })
                 .unwrap();
 
         let io = Rc::new(TvixStoreIO::new(
             blob_service,
             directory_service,
-            path_info_service.into(),
+            path_info_service,
             nar_calculation_service.into(),
             Arc::<DummyBuildService>::default(),
             tokio_runtime.handle().clone(),
         ));
-        let mut eval = tvix_eval::Evaluation::new(io.clone() as Rc<dyn EvalIO>, true);
 
-        add_derivation_builtins(&mut eval, io.clone());
-        add_fetcher_builtins(&mut eval, io.clone());
-        add_import_builtins(&mut eval, io);
+        let mut eval_builder =
+            tvix_eval::Evaluation::builder(io.clone() as Rc<dyn EvalIO>).enable_import();
+        eval_builder = add_derivation_builtins(eval_builder, Rc::clone(&io));
+        eval_builder = add_fetcher_builtins(eval_builder, Rc::clone(&io));
+        eval_builder = add_import_builtins(eval_builder, io);
+        let eval = eval_builder.build();
 
         // run the evaluation itself.
         eval.evaluate(str, None)