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-rw-r--r--tvix/glue/src/builtins/mod.rs797
1 files changed, 797 insertions, 0 deletions
diff --git a/tvix/glue/src/builtins/mod.rs b/tvix/glue/src/builtins/mod.rs
new file mode 100644
index 0000000000..0c7bcc880a
--- /dev/null
+++ b/tvix/glue/src/builtins/mod.rs
@@ -0,0 +1,797 @@
+//! Contains builtins that deal with the store or builder.
+
+use std::rc::Rc;
+
+use crate::tvix_store_io::TvixStoreIO;
+
+mod derivation;
+mod errors;
+mod fetchers;
+mod import;
+mod utils;
+
+pub use errors::{DerivationError, FetcherError, ImportError};
+
+/// Adds derivation-related builtins to the passed [tvix_eval::Evaluation].
+///
+/// These are `derivation` and `derivationStrict`.
+///
+/// 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")));
+}
+
+/// Adds fetcher builtins to the passed [tvix_eval::Evaluation]:
+///
+/// * `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)));
+}
+
+/// Adds import-related builtins to the passed [tvix_eval::Evaluation].
+///
+/// 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));
+
+    // TODO(raitobezarius): evaluate expressing filterSource as Nix code using path (b/372)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::{fs, rc::Rc, sync::Arc};
+
+    use crate::tvix_store_io::TvixStoreIO;
+
+    use super::{add_derivation_builtins, add_fetcher_builtins, add_import_builtins};
+    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;
+
+    /// evaluates a given nix expression and returns the result.
+    /// Takes care of setting up the evaluator so it knows about the
+    // `derivation` builtin.
+    fn eval(str: &str) -> EvaluationResult {
+        // 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) = runtime
+            .block_on(async { construct_services("memory://", "memory://", "memory://").await })
+            .expect("Failed to construct store services in memory");
+
+        let io = Rc::new(TvixStoreIO::new(
+            blob_service,
+            directory_service,
+            path_info_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);
+
+        // run the evaluation itself.
+        eval.evaluate(str, None)
+    }
+
+    #[test]
+    fn derivation() {
+        let result = eval(
+            r#"(derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux";}).outPath"#,
+        );
+
+        assert!(result.errors.is_empty(), "expect evaluation to succeed");
+        let value = result.value.expect("must be some");
+
+        match value {
+            tvix_eval::Value::String(s) => {
+                assert_eq!(*s, "/nix/store/xpcvxsx5sw4rbq666blz6sxqlmsqphmr-foo",);
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+    }
+
+    /// a derivation with an empty name is an error.
+    #[test]
+    fn derivation_empty_name_fail() {
+        let result = eval(
+            r#"(derivation { name = ""; builder = "/bin/sh"; system = "x86_64-linux";}).outPath"#,
+        );
+
+        assert!(!result.errors.is_empty(), "expect evaluation to fail");
+    }
+
+    /// construct some calls to builtins.derivation and compare produced output
+    /// paths.
+    #[rstest]
+    #[case::r_sha256(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#, "/nix/store/17wgs52s7kcamcyin4ja58njkf91ipq8-foo")]
+    #[case::r_sha256_other_name(r#"(builtins.derivation { name = "foo2"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#, "/nix/store/gi0p8vd635vpk1nq029cz3aa3jkhar5k-foo2")]
+    #[case::r_sha1(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha1"; outputHash = "sha1-VUCRC+16gU5lcrLYHlPSUyx0Y/Q="; }).outPath"#, "/nix/store/p5sammmhpa84ama7ymkbgwwzrilva24x-foo")]
+    #[case::r_md5(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "md5"; outputHash = "md5-07BzhNET7exJ6qYjitX/AA=="; }).outPath"#, "/nix/store/gmmxgpy1jrzs86r5y05wy6wiy2m15xgi-foo")]
+    #[case::r_sha512(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha512"; outputHash = "sha512-DPkYCnZKuoY6Z7bXLwkYvBMcZ3JkLLLc5aNPCnAvlHDdwr8SXBIZixmVwjPDS0r9NGxUojNMNQqUilG26LTmtg=="; }).outPath"#, "/nix/store/lfi2bfyyap88y45mfdwi4j99gkaxaj19-foo")]
+    #[case::r_sha256_base16(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "4374173a8cbe88de152b609f96f46e958bcf65762017474eec5a05ec2bd61530"; }).outPath"#, "/nix/store/17wgs52s7kcamcyin4ja58njkf91ipq8-foo")]
+    #[case::r_sha256_nixbase32(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "0c0msqmyq1asxi74f5r0frjwz2wmdvs9d7v05caxx25yihx1fx23"; }).outPath"#, "/nix/store/17wgs52s7kcamcyin4ja58njkf91ipq8-foo")]
+    #[case::r_sha256_base64(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#, "/nix/store/17wgs52s7kcamcyin4ja58njkf91ipq8-foo")]
+    #[case::r_sha256_base64_nopad(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "sha256-fgIr3TyFGDAXP5+qoAaiMKDg/a1MlT6Fv/S/DaA24S8="; }).outPath"#, "/nix/store/xm1l9dx4zgycv9qdhcqqvji1z88z534b-foo")]
+    #[case::sha256(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "flat"; outputHashAlgo = "sha256"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#, "/nix/store/q4pkwkxdib797fhk22p0k3g1q32jmxvf-foo")]
+    #[case::sha256_other_name(r#"(builtins.derivation { name = "foo2"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "flat"; outputHashAlgo = "sha256"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#, "/nix/store/znw17xlmx9r6gw8izjkqxkl6s28sza4l-foo2")]
+    #[case::sha1(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "flat"; outputHashAlgo = "sha1"; outputHash = "sha1-VUCRC+16gU5lcrLYHlPSUyx0Y/Q="; }).outPath"#, "/nix/store/zgpnjjmga53d8srp8chh3m9fn7nnbdv6-foo")]
+    #[case::md5(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "flat"; outputHashAlgo = "md5"; outputHash = "md5-07BzhNET7exJ6qYjitX/AA=="; }).outPath"#, "/nix/store/jfhcwnq1852ccy9ad9nakybp2wadngnd-foo")]
+    #[case::sha512(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "flat"; outputHashAlgo = "sha512"; outputHash = "sha512-DPkYCnZKuoY6Z7bXLwkYvBMcZ3JkLLLc5aNPCnAvlHDdwr8SXBIZixmVwjPDS0r9NGxUojNMNQqUilG26LTmtg=="; }).outPath"#, "/nix/store/as736rr116ian9qzg457f96j52ki8bm3-foo")]
+    #[case::r_sha256_outputhashalgo_omitted(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#, "/nix/store/17wgs52s7kcamcyin4ja58njkf91ipq8-foo")]
+    #[case::r_sha256_outputhashalgo_and_outputhashmode_omitted(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#, "/nix/store/q4pkwkxdib797fhk22p0k3g1q32jmxvf-foo")]
+    #[case::outputhash_omitted(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; }).outPath"#, "/nix/store/xpcvxsx5sw4rbq666blz6sxqlmsqphmr-foo")]
+    #[case::multiple_outputs(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; outputs = ["foo" "bar"]; system = "x86_64-linux"; }).outPath"#, "/nix/store/hkwdinvz2jpzgnjy9lv34d2zxvclj4s3-foo-foo")]
+    #[case::args(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; args = ["--foo" "42" "--bar"]; system = "x86_64-linux"; }).outPath"#, "/nix/store/365gi78n2z7vwc1bvgb98k0a9cqfp6as-foo")]
+    #[case::full(r#"
+                   let
+                     bar = builtins.derivation {
+                       name = "bar";
+                       builder = ":";
+                       system = ":";
+                       outputHash = "08813cbee9903c62be4c5027726a418a300da4500b2d369d3af9286f4815ceba";
+                       outputHashAlgo = "sha256";
+                       outputHashMode = "recursive";
+                     };
+                   in
+                   (builtins.derivation {
+                     name = "foo";
+                     builder = ":";
+                     system = ":";
+                     inherit bar;
+                   }).outPath
+        "#, "/nix/store/5vyvcwah9l9kf07d52rcgdk70g2f4y13-foo")]
+    #[case::pass_as_file(r#"(builtins.derivation { "name" = "foo"; passAsFile = ["bar"]; bar = "baz"; system = ":"; builder = ":";}).outPath"#, "/nix/store/25gf0r1ikgmh4vchrn8qlc4fnqlsa5a1-foo")]
+    // __ignoreNulls = true, but nothing set to null
+    #[case::ignore_nulls_true_no_arg_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = true; }).drvPath"#, "/nix/store/xa96w6d7fxrlkk60z1fmx2ffp2wzmbqx-foo.drv")]
+    #[case::ignore_nulls_true_no_arg_outpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = true; }).outPath"#, "/nix/store/pk2agn9za8r9bxsflgh1y7fyyrmwcqkn-foo")]
+    // __ignoreNulls = true, with a null arg, same paths
+    #[case::ignore_nulls_true_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = true; ignoreme = null; }).drvPath"#, "/nix/store/xa96w6d7fxrlkk60z1fmx2ffp2wzmbqx-foo.drv")]
+    #[case::ignore_nulls_true_outpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = true; ignoreme = null; }).outPath"#, "/nix/store/pk2agn9za8r9bxsflgh1y7fyyrmwcqkn-foo")]
+    // __ignoreNulls = false
+    #[case::ignore_nulls_false_no_arg_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = false; }).drvPath"#, "/nix/store/xa96w6d7fxrlkk60z1fmx2ffp2wzmbqx-foo.drv")]
+    #[case::ignore_nulls_false_no_arg_outpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = false; }).outPath"#, "/nix/store/pk2agn9za8r9bxsflgh1y7fyyrmwcqkn-foo")]
+    // __ignoreNulls = false, with a null arg
+    #[case::ignore_nulls_fales_arg_path_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = false; foo = null; }).drvPath"#, "/nix/store/xwkwbajfiyhdqmksrbzm0s4g4ib8d4ms-foo.drv")]
+    #[case::ignore_nulls_fales_arg_path_outpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = false; foo = null; }).outPath"#, "/nix/store/2n2jqm6l7r2ahi19m58pl896ipx9cyx6-foo")]
+    // structured attrs set to false will render an empty string inside env
+    #[case::structured_attrs_false_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __structuredAttrs = false; foo = "bar"; }).drvPath"#, "/nix/store/qs39krwr2lsw6ac910vqx4pnk6m63333-foo.drv")]
+    #[case::structured_attrs_false_outpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __structuredAttrs = false; foo = "bar"; }).outPath"#, "/nix/store/9yy3764rdip3fbm8ckaw4j9y7vh4d231-foo")]
+    // simple structured attrs
+    #[case::structured_attrs_simple_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __structuredAttrs = true; foo = "bar"; }).drvPath"#, "/nix/store/k6rlb4k10cb9iay283037ml1nv3xma2f-foo.drv")]
+    #[case::structured_attrs_simple_outpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __structuredAttrs = true; foo = "bar"; }).outPath"#, "/nix/store/6lmv3hyha1g4cb426iwjyifd7nrdv1xn-foo")]
+    // structured attrs with outputsCheck
+    #[case::structured_attrs_output_checks_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __structuredAttrs = true; foo = "bar"; outputChecks = {out = {maxClosureSize = 256 * 1024 * 1024; disallowedRequisites = [ "dev" ];};}; }).drvPath"#, "/nix/store/fx9qzpchh5wchchhy39bwsml978d6wp1-foo.drv")]
+    #[case::structured_attrs_output_checks_outpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __structuredAttrs = true; foo = "bar"; outputChecks = {out = {maxClosureSize = 256 * 1024 * 1024; disallowedRequisites = [ "dev" ];};}; }).outPath"#, "/nix/store/pcywah1nwym69rzqdvpp03sphfjgyw1l-foo")]
+    // structured attrs and __ignoreNulls. ignoreNulls is inactive (so foo ends up in __json, yet __ignoreNulls itself is not present.
+    #[case::structured_attrs_and_ignore_nulls_drvpath(r#"(builtins.derivation { name = "foo"; system = ":"; builder = ":"; __ignoreNulls = false; foo = null; __structuredAttrs = true; }).drvPath"#, "/nix/store/rldskjdcwa3p7x5bqy3r217va1jsbjsc-foo.drv")]
+    // structured attrs, setting outputs.
+    #[case::structured_attrs_outputs_drvpath(r#"(builtins.derivation { name = "test"; system = "aarch64-linux"; builder = "/bin/sh"; __structuredAttrs = true; outputs = [ "out"]; }).drvPath"#, "/nix/store/6sgawp30zibsh525p7c948xxd22y2ngy-test.drv")]
+    fn test_outpath(#[case] code: &str, #[case] expected_path: &str) {
+        let value = eval(code).value.expect("must succeed");
+
+        match value {
+            tvix_eval::Value::String(s) => {
+                assert_eq!(*s, expected_path);
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+    }
+
+    /// construct some calls to builtins.derivation that should be rejected
+    #[rstest]
+    #[case::invalid_outputhash(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "sha256-00"; }).outPath"#)]
+    #[case::sha1_and_sha256(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha1"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath"#)]
+    #[case::duplicate_output_names(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; outputs = ["foo" "foo"]; system = "x86_64-linux"; }).outPath"#)]
+    fn test_outpath_invalid(#[case] code: &str) {
+        let resp = eval(code);
+        assert!(resp.value.is_none(), "Value should be None");
+        assert!(
+            !resp.errors.is_empty(),
+            "There should have been some errors"
+        );
+    }
+
+    /// Construct two FODs with the same name, and same known output (but
+    /// slightly different recipe), ensure they have the same output hash.
+    #[test]
+    fn test_fod_outpath() {
+        let code = r#"
+          (builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath ==
+          (builtins.derivation { name = "foo"; builder = "/bin/aa"; system = "x86_64-linux"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath
+        "#;
+
+        let value = eval(code).value.expect("must succeed");
+        match value {
+            tvix_eval::Value::Bool(v) => {
+                assert!(v);
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+    }
+
+    /// Construct two FODs with the same name, and same known output (but
+    /// slightly different recipe), ensure they have the same output hash.
+    #[test]
+    fn test_fod_outpath_different_name() {
+        let code = r#"
+          (builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath ==
+          (builtins.derivation { name = "foo"; builder = "/bin/aa"; system = "x86_64-linux"; outputHash = "sha256-Q3QXOoy+iN4VK2CflvRulYvPZXYgF0dO7FoF7CvWFTA="; }).outPath
+        "#;
+
+        let value = eval(code).value.expect("must succeed");
+        match value {
+            tvix_eval::Value::Bool(v) => {
+                assert!(v);
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+    }
+
+    /// Construct two derivations with the same parameters except one of them lost a context string
+    /// for a dependency, causing the loss of an element in the `inputDrvs` derivation. Therefore,
+    /// making `outPath` different.
+    #[test]
+    fn test_unsafe_discard_string_context() {
+        let code = r#"
+        let
+            dep = builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; };
+        in
+          (builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; env = "${dep}"; }).outPath !=
+          (builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; env = "${builtins.unsafeDiscardStringContext dep}"; }).outPath
+        "#;
+
+        let value = eval(code).value.expect("must succeed");
+        match value {
+            tvix_eval::Value::Bool(v) => {
+                assert!(v);
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+    }
+
+    /// Construct an attribute set that coerces to a derivation and verify that the return type is
+    /// a string.
+    #[test]
+    fn test_unsafe_discard_string_context_of_coercible() {
+        let code = r#"
+        let
+            dep = builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; };
+            attr = { __toString = _: dep; };
+        in
+            builtins.typeOf (builtins.unsafeDiscardStringContext attr) == "string"
+        "#;
+
+        let value = eval(code).value.expect("must succeed");
+        match value {
+            tvix_eval::Value::Bool(v) => {
+                assert!(v);
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+    }
+
+    #[rstest]
+    #[case::input_in_args(r#"
+                   let
+                     bar = builtins.derivation {
+                       name = "bar";
+                       builder = ":";
+                       system = ":";
+                       outputHash = "08813cbee9903c62be4c5027726a418a300da4500b2d369d3af9286f4815ceba";
+                       outputHashAlgo = "sha256";
+                       outputHashMode = "recursive";
+                     };
+                   in
+                   (builtins.derivation {
+                     name = "foo";
+                     builder = ":";
+                     args = [ "${bar}" ];
+                     system = ":";
+                   }).drvPath
+        "#, "/nix/store/50yl2gmmljyl0lzyrp1mcyhn53vhjhkd-foo.drv")]
+    fn test_inputs_derivation_from_context(#[case] code: &str, #[case] expected_drvpath: &str) {
+        let eval_result = eval(code);
+
+        let value = eval_result.value.expect("must succeed");
+
+        match value {
+            tvix_eval::Value::String(s) => {
+                assert_eq!(*s, expected_drvpath);
+            }
+
+            _ => panic!("unexpected value type: {:?}", value),
+        };
+    }
+
+    #[test]
+    fn builtins_placeholder_hashes() {
+        assert_eq!(
+            hash_placeholder("out").as_str(),
+            "/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9"
+        );
+
+        assert_eq!(
+            hash_placeholder("").as_str(),
+            "/171rf4jhx57xqz3p7swniwkig249cif71pa08p80mgaf0mqz5bmr"
+        );
+    }
+
+    /// constructs calls to builtins.derivation that should succeed, but produce warnings
+    #[rstest]
+    #[case::r_sha256_wrong_padding(r#"(builtins.derivation { name = "foo"; builder = "/bin/sh"; system = "x86_64-linux"; outputHashMode = "recursive"; outputHashAlgo = "sha256"; outputHash = "sha256-fgIr3TyFGDAXP5+qoAaiMKDg/a1MlT6Fv/S/DaA24S8===="; }).outPath"#, "/nix/store/xm1l9dx4zgycv9qdhcqqvji1z88z534b-foo")]
+    fn builtins_derivation_hash_wrong_padding_warn(
+        #[case] code: &str,
+        #[case] expected_path: &str,
+    ) {
+        let eval_result = eval(code);
+
+        let value = eval_result.value.expect("must succeed");
+
+        match value {
+            tvix_eval::Value::String(s) => {
+                assert_eq!(*s, expected_path);
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+
+        assert!(
+            !eval_result.warnings.is_empty(),
+            "warnings should not be empty"
+        );
+    }
+
+    /// Invokes `builtins.filterSource` on various carefully-crated subdirs, and
+    /// ensures the resulting store paths matches what Nix produces.
+    /// @fixtures is replaced to the fixtures directory.
+    #[rstest]
+    #[cfg(target_family = "unix")]
+    #[case::complicated_filter_nothing(
+        r#"(builtins.filterSource (p: t: true) @fixtures)"#,
+        "/nix/store/bqh6kd0x3vps2rzagzpl7qmbbgnx19cp-import_fixtures"
+    )]
+    #[case::complicated_filter_everything(
+        r#"(builtins.filterSource (p: t: false) @fixtures)"#,
+        "/nix/store/giq6czz24lpjg97xxcxk6rg950lcpib1-import_fixtures"
+    )]
+    #[case::simple_dir_with_one_file_filter_dirs(
+        r#"(builtins.filterSource (p: t: t != "directory") @fixtures/a_dir)"#,
+        "/nix/store/8vbqaxapywkvv1hacdja3pi075r14d43-a_dir"
+    )]
+    #[case::simple_dir_with_one_file_filter_files(
+        r#"(builtins.filterSource (p: t: t != "regular") @fixtures/a_dir)"#,
+        "/nix/store/zphlqc93s2iq4xm393l06hzf8hp85r4z-a_dir"
+    )]
+    #[case::simple_dir_with_one_file_filter_symlinks(
+        r#"(builtins.filterSource (p: t: t != "symlink") @fixtures/a_dir)"#,
+        "/nix/store/8vbqaxapywkvv1hacdja3pi075r14d43-a_dir"
+    )]
+    #[case::simple_dir_with_one_file_filter_nothing(
+        r#"(builtins.filterSource (p: t: true) @fixtures/a_dir)"#,
+        "/nix/store/8vbqaxapywkvv1hacdja3pi075r14d43-a_dir"
+    )]
+    #[case::simple_dir_with_one_file_filter_everything(
+        r#"(builtins.filterSource (p: t: false) @fixtures/a_dir)"#,
+        "/nix/store/zphlqc93s2iq4xm393l06hzf8hp85r4z-a_dir"
+    )]
+    #[case::simple_dir_with_one_dir_filter_dirs(
+        r#"builtins.filterSource (p: t: t != "directory") @fixtures/b_dir"#,
+        "/nix/store/xzsfzdgrxg93icaamjm8zq1jq6xvf2fz-b_dir"
+    )]
+    #[case::simple_dir_with_one_dir_filter_files(
+        r#"builtins.filterSource (p: t: t != "regular") @fixtures/b_dir"#,
+        "/nix/store/8rjx64mm7173xp60rahv7cl3ixfkv3rf-b_dir"
+    )]
+    #[case::simple_dir_with_one_dir_filter_symlinks(
+        r#"builtins.filterSource (p: t: t != "symlink") @fixtures/b_dir"#,
+        "/nix/store/8rjx64mm7173xp60rahv7cl3ixfkv3rf-b_dir"
+    )]
+    #[case::simple_dir_with_one_dir_filter_nothing(
+        r#"builtins.filterSource (p: t: true) @fixtures/b_dir"#,
+        "/nix/store/8rjx64mm7173xp60rahv7cl3ixfkv3rf-b_dir"
+    )]
+    #[case::simple_dir_with_one_dir_filter_everything(
+        r#"builtins.filterSource (p: t: false) @fixtures/b_dir"#,
+        "/nix/store/xzsfzdgrxg93icaamjm8zq1jq6xvf2fz-b_dir"
+    )]
+    #[case::simple_dir_with_one_symlink_to_file_filter_dirs(
+        r#"builtins.filterSource (p: t: t != "directory") @fixtures/c_dir"#,
+        "/nix/store/riigfmmzzrq65zqiffcjk5sbqr9c9h09-c_dir"
+    )]
+    #[case::simple_dir_with_one_symlink_to_file_filter_files(
+        r#"builtins.filterSource (p: t: t != "regular") @fixtures/c_dir"#,
+        "/nix/store/riigfmmzzrq65zqiffcjk5sbqr9c9h09-c_dir"
+    )]
+    #[case::simple_dir_with_one_symlink_to_file_filter_symlinks(
+        r#"builtins.filterSource (p: t: t != "symlink") @fixtures/c_dir"#,
+        "/nix/store/y5g1fz04vzjvf422q92qmv532axj5q26-c_dir"
+    )]
+    #[case::simple_dir_with_one_symlink_to_file_filter_nothing(
+        r#"builtins.filterSource (p: t: true) @fixtures/c_dir"#,
+        "/nix/store/riigfmmzzrq65zqiffcjk5sbqr9c9h09-c_dir"
+    )]
+    #[case::simple_dir_with_one_symlink_to_file_filter_everything(
+        r#"builtins.filterSource (p: t: false) @fixtures/c_dir"#,
+        "/nix/store/y5g1fz04vzjvf422q92qmv532axj5q26-c_dir"
+    )]
+    #[case::simple_dir_with_dangling_symlink_filter_dirs(
+        r#"builtins.filterSource (p: t: t != "directory") @fixtures/d_dir"#,
+        "/nix/store/f2d1aixwiqy4lbzrd040ala2s4m2z199-d_dir"
+    )]
+    #[case::simple_dir_with_dangling_symlink_filter_files(
+        r#"builtins.filterSource (p: t: t != "regular") @fixtures/d_dir"#,
+        "/nix/store/f2d1aixwiqy4lbzrd040ala2s4m2z199-d_dir"
+    )]
+    #[case::simple_dir_with_dangling_symlink_filter_symlinks(
+        r#"builtins.filterSource (p: t: t != "symlink") @fixtures/d_dir"#,
+        "/nix/store/7l371xax8kknhpska4wrmyll1mzlhzvl-d_dir"
+    )]
+    #[case::simple_dir_with_dangling_symlink_filter_nothing(
+        r#"builtins.filterSource (p: t: true) @fixtures/d_dir"#,
+        "/nix/store/f2d1aixwiqy4lbzrd040ala2s4m2z199-d_dir"
+    )]
+    #[case::simple_dir_with_dangling_symlink_filter_everything(
+        r#"builtins.filterSource (p: t: false) @fixtures/d_dir"#,
+        "/nix/store/7l371xax8kknhpska4wrmyll1mzlhzvl-d_dir"
+    )]
+    #[case::simple_symlinked_dir_with_one_file_filter_dirs(
+        r#"builtins.filterSource (p: t: t != "directory") @fixtures/symlink_to_a_dir"#,
+        "/nix/store/apmdprm8fwl2zrjpbyfcd99zrnhvf47q-symlink_to_a_dir"
+    )]
+    #[case::simple_symlinked_dir_with_one_file_filter_files(
+        r#"builtins.filterSource (p: t: t != "regular") @fixtures/symlink_to_a_dir"#,
+        "/nix/store/apmdprm8fwl2zrjpbyfcd99zrnhvf47q-symlink_to_a_dir"
+    )]
+    #[case::simple_symlinked_dir_with_one_file_filter_symlinks(
+        r#"builtins.filterSource (p: t: t != "symlink") @fixtures/symlink_to_a_dir"#,
+        "/nix/store/apmdprm8fwl2zrjpbyfcd99zrnhvf47q-symlink_to_a_dir"
+    )]
+    #[case::simple_symlinked_dir_with_one_file_filter_nothing(
+        r#"builtins.filterSource (p: t: true) @fixtures/symlink_to_a_dir"#,
+        "/nix/store/apmdprm8fwl2zrjpbyfcd99zrnhvf47q-symlink_to_a_dir"
+    )]
+    #[case::simple_symlinked_dir_with_one_file_filter_everything(
+        r#"builtins.filterSource (p: t: false) @fixtures/symlink_to_a_dir"#,
+        "/nix/store/apmdprm8fwl2zrjpbyfcd99zrnhvf47q-symlink_to_a_dir"
+    )]
+    fn builtins_filter_source_succeed(#[case] code: &str, #[case] expected_outpath: &str) {
+        // populate the fixtures dir
+        let temp = TempDir::new().expect("create temporary directory");
+        let p = temp.path().join("import_fixtures");
+
+        // create the fixtures directory.
+        // We produce them at runtime rather than shipping it inside the source
+        // tree, as git can't model certain things - like directories without any
+        // items.
+        {
+            fs::create_dir(&p).expect("creating import_fixtures");
+
+            // `/a_dir` contains an empty `a_file` file
+            fs::create_dir(p.join("a_dir")).expect("creating /a_dir");
+            fs::write(p.join("a_dir").join("a_file"), "").expect("creating /a_dir/a_file");
+
+            // `/a_file` is an empty file
+            fs::write(p.join("a_file"), "").expect("creating /a_file");
+
+            // `/b_dir` contains an empty "a_dir" directory
+            fs::create_dir_all(p.join("b_dir").join("a_dir")).expect("creating /b_dir/a_dir");
+
+            // `/c_dir` contains a `symlink_to_a_file` symlink, pointing to `../a_dir/a_file`.
+            fs::create_dir(p.join("c_dir")).expect("creating /c_dir");
+            std::os::unix::fs::symlink(
+                "../a_dir/a_file",
+                p.join("c_dir").join("symlink_to_a_file"),
+            )
+            .expect("creating /c_dir/symlink_to_a_file");
+
+            // `/d_dir` contains a `dangling_symlink`, pointing to `a_dir/a_file`,
+            // which does not exist.
+            fs::create_dir(p.join("d_dir")).expect("creating /d_dir");
+            std::os::unix::fs::symlink("a_dir/a_file", p.join("d_dir").join("dangling_symlink"))
+                .expect("creating /d_dir/dangling_symlink");
+
+            // `/symlink_to_a_dir` is a symlink to `a_dir`, which exists.
+            std::os::unix::fs::symlink("a_dir", p.join("symlink_to_a_dir"))
+                .expect("creating /symlink_to_a_dir");
+        }
+
+        // replace @fixtures with the temporary path containing the fixtures
+        let code_replaced = code.replace("@fixtures", &p.to_string_lossy());
+
+        let eval_result = eval(&code_replaced);
+
+        let value = eval_result.value.expect("must succeed");
+
+        match value {
+            tvix_eval::Value::String(s) => {
+                assert_eq!(expected_outpath, s.as_bstr());
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+
+        assert!(eval_result.errors.is_empty(), "errors should be empty");
+    }
+
+    // Space is an illegal character.
+    #[rstest]
+    #[case(
+        r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = true; })"#,
+        true
+    )]
+    // Space is still an illegal character.
+    #[case(
+        r#"(builtins.path { name = "invalid name"; path = @fixtures + "/te st"; recursive = true; })"#,
+        false
+    )]
+    fn builtins_path_recursive_rename(#[case] code: &str, #[case] success: bool) {
+        // populate the fixtures dir
+        let temp = TempDir::new().expect("create temporary directory");
+        let p = temp.path().join("import_fixtures");
+
+        // create the fixtures directory.
+        // We produce them at runtime rather than shipping it inside the source
+        // tree, as git can't model certain things - like directories without any
+        // items.
+        {
+            fs::create_dir(&p).expect("creating import_fixtures");
+            fs::write(p.join("te st"), "").expect("creating `/te st`");
+        }
+        // replace @fixtures with the temporary path containing the fixtures
+        let code_replaced = code.replace("@fixtures", &p.to_string_lossy());
+
+        let eval_result = eval(&code_replaced);
+
+        let value = eval_result.value;
+
+        if success {
+            match value.expect("expected successful evaluation on legal rename") {
+                tvix_eval::Value::String(s) => {
+                    assert_eq!(
+                        "/nix/store/nd5z11x7zjqqz44rkbhc6v7yifdkn659-valid-name",
+                        s.as_bstr()
+                    );
+                }
+                v => panic!("unexpected value type: {:?}", v),
+            }
+        } else {
+            assert!(value.is_none(), "unexpected success on illegal store paths");
+        }
+    }
+
+    // Space is an illegal character.
+    #[rstest]
+    #[case(
+        r#"(builtins.path { name = "valid-name"; path = @fixtures + "/te st"; recursive = false; })"#,
+        true
+    )]
+    // Space is still an illegal character.
+    #[case(
+        r#"(builtins.path { name = "invalid name"; path = @fixtures + "/te st"; recursive = false; })"#,
+        false
+    )]
+    // The non-recursive variant passes explicitly `recursive = false;`
+    fn builtins_path_nonrecursive_rename(#[case] code: &str, #[case] success: bool) {
+        // populate the fixtures dir
+        let temp = TempDir::new().expect("create temporary directory");
+        let p = temp.path().join("import_fixtures");
+
+        // create the fixtures directory.
+        // We produce them at runtime rather than shipping it inside the source
+        // tree, as git can't model certain things - like directories without any
+        // items.
+        {
+            fs::create_dir(&p).expect("creating import_fixtures");
+            fs::write(p.join("te st"), "").expect("creating `/te st`");
+        }
+        // replace @fixtures with the temporary path containing the fixtures
+        let code_replaced = code.replace("@fixtures", &p.to_string_lossy());
+
+        let eval_result = eval(&code_replaced);
+
+        let value = eval_result.value;
+
+        if success {
+            match value.expect("expected successful evaluation on legal rename") {
+                tvix_eval::Value::String(s) => {
+                    assert_eq!(
+                        "/nix/store/il2rmfbqgs37rshr8w7x64hd4d3b4bsa-valid-name",
+                        s.as_bstr()
+                    );
+                }
+                v => panic!("unexpected value type: {:?}", v),
+            }
+        } else {
+            assert!(value.is_none(), "unexpected success on illegal store paths");
+        }
+    }
+
+    #[rstest]
+    #[case(
+        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="; })"#,
+        false
+    )]
+    #[case(
+        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="; })"#,
+        false
+    )]
+    fn builtins_path_fod_locking(#[case] code: &str, #[case] exp_success: bool) {
+        // populate the fixtures dir
+        let temp = TempDir::new().expect("create temporary directory");
+        let p = temp.path().join("import_fixtures");
+
+        // create the fixtures directory.
+        // We produce them at runtime rather than shipping it inside the source
+        // tree, as git can't model certain things - like directories without any
+        // items.
+        {
+            fs::create_dir(&p).expect("creating import_fixtures");
+            fs::write(p.join("te st"), "").expect("creating `/te st`");
+        }
+        // replace @fixtures with the temporary path containing the fixtures
+        let code_replaced = code.replace("@fixtures", &p.to_string_lossy());
+
+        let eval_result = eval(&code_replaced);
+
+        let value = eval_result.value;
+
+        if exp_success {
+            assert!(
+                value.is_some(),
+                "expected successful evaluation on legal rename and valid FOD sha256"
+            );
+        } else {
+            assert!(value.is_none(), "unexpected success on invalid FOD sha256");
+        }
+    }
+
+    #[rstest]
+    #[case(
+        r#"(builtins.path { name = "valid-path"; path = @fixtures + "/te st dir"; filter = _: _: true; })"#,
+        "/nix/store/i28jmi4fwym4fw3flkrkp2mdxx50pdy0-valid-path"
+    )]
+    #[case(
+        r#"(builtins.path { name = "valid-path"; path = @fixtures + "/te st dir"; filter = _: _: false; })"#,
+        "/nix/store/pwza2ij9gk1fmzhbjnynmfv2mq2sgcap-valid-path"
+    )]
+    fn builtins_path_filter(#[case] code: &str, #[case] expected_outpath: &str) {
+        // populate the fixtures dir
+        let temp = TempDir::new().expect("create temporary directory");
+        let p = temp.path().join("import_fixtures");
+
+        // create the fixtures directory.
+        // We produce them at runtime rather than shipping it inside the source
+        // tree, as git can't model certain things - like directories without any
+        // items.
+        {
+            fs::create_dir(&p).expect("creating import_fixtures");
+            fs::create_dir(p.join("te st dir")).expect("creating `/te st dir`");
+            fs::write(p.join("te st dir").join("test"), "").expect("creating `/te st dir/test`");
+        }
+        // replace @fixtures with the temporary path containing the fixtures
+        let code_replaced = code.replace("@fixtures", &p.to_string_lossy());
+
+        let eval_result = eval(&code_replaced);
+
+        let value = eval_result.value.expect("must succeed");
+
+        match value {
+            tvix_eval::Value::String(s) => {
+                assert_eq!(expected_outpath, s.as_bstr());
+            }
+            _ => panic!("unexpected value type: {:?}", value),
+        }
+
+        assert!(eval_result.errors.is_empty(), "errors should be empty");
+    }
+
+    // All tests filter out some unsupported (not representable in castore) nodes, confirming
+    // invalid, but filtered-out nodes don't prevent ingestion of a path.
+    #[rstest]
+    #[cfg(target_family = "unix")]
+    // There is a set of invalid filetypes.
+    // We write various filter functions filtering them out, but usually leaving
+    // some behind.
+    // In case there's still invalid filetypes left after the filtering, we
+    // expect the evaluation to fail.
+    #[case::fail_kept_unknowns(
+        r#"(builtins.filterSource (p: t: t == "unknown") @fixtures)"#,
+        false
+    )]
+    // We filter all invalid filetypes, so the evaluation has to succeed.
+    #[case::succeed_filter_unknowns(
+        r#"(builtins.filterSource (p: t: t != "unknown") @fixtures)"#,
+        true
+    )]
+    #[case::fail_kept_charnode(
+        r#"(builtins.filterSource (p: t: (builtins.baseNameOf p) != "a_charnode") @fixtures)"#,
+        false
+    )]
+    #[case::fail_kept_socket(
+        r#"(builtins.filterSource (p: t: (builtins.baseNameOf p) != "a_socket") @fixtures)"#,
+        false
+    )]
+    #[case::fail_kept_fifo(
+        r#"(builtins.filterSource (p: t: (builtins.baseNameOf p) != "a_fifo") @fixtures)"#,
+        false
+    )]
+    fn builtins_filter_source_unsupported_files(#[case] code: &str, #[case] exp_success: bool) {
+        use nix::errno::Errno;
+        use nix::sys::stat;
+        use nix::unistd;
+        use std::os::unix::net::UnixListener;
+        use tempfile::TempDir;
+
+        // We prepare a directory containing some unsupported file nodes:
+        // - character device
+        // - socket
+        // - FIFO
+        // and we run the evaluation inside that CWD.
+        //
+        // block devices cannot be tested because we don't have the right permissions.
+        let temp = TempDir::with_prefix("foo").expect("Failed to create a temporary directory");
+
+        // read, write, execute to the owner.
+        unistd::mkfifo(&temp.path().join("a_fifo"), stat::Mode::S_IRWXU)
+            .expect("Failed to create the FIFO");
+
+        UnixListener::bind(temp.path().join("a_socket")).expect("Failed to create the socket");
+
+        stat::mknod(
+            &temp.path().join("a_charnode"),
+            stat::SFlag::S_IFCHR,
+            stat::Mode::S_IRWXU,
+            0,
+        )
+        .inspect_err(|e| {
+            if *e == Errno::EPERM {
+                eprintln!(
+                    "\
+Missing permissions to create a character device node with mknod(2).
+Please run this test as root or set CAP_MKNOD."
+                );
+            }
+        })
+        .expect("Failed to create a character device node");
+
+        let code_replaced = code.replace("@fixtures", &temp.path().to_string_lossy());
+        let eval_result = eval(&code_replaced);
+
+        if exp_success {
+            assert!(
+                eval_result.value.is_some(),
+                "unexpected failure on a directory of unsupported file types but all filtered: {:?}",
+                eval_result.errors
+            );
+        } else {
+            assert!(
+                eval_result.value.is_none(),
+                "unexpected success on unsupported file type ingestion: {:?}",
+                eval_result.value
+            );
+        }
+    }
+}