refactor(tvix/store): use strictly typed PathInfo struct r/8787

This switches the PathInfoService trait from using the proto-derived
PathInfo struct to a more restrictive struct, and updates all
implementations to use it.

It removes a lot of the previous conversion and checks, as invalid
states became nonrepresentable, and validations are expressed on the
type level.

PathInfoService implementations consuming protobuf need to convert and
do the verification internally, and can only return the strongly typed
variant.

The nix_compat::narinfo::NarInfo conversions for the proto PathInfo
are removed, we only keep a version showing a NarInfo representation for
the strong struct.

Converting back to a PathInfo requires the root node now, but is
otherwise trivial, so left to the users.

Co-Authored-By: Florian Klink <flokli@flokli.de>
Change-Id: I6fdfdb44063efebb44a8f0097b6b81a828717e03
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12588
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

1 files changed, 31 insertions, 57 deletions

diff --git a/tvix/glue/src/tvix_store_io.rs b/tvix/glue/src/tvix_store_io.rs
index 8a11e293f0ac..3af7ee1306ed 100644
--- a/tvix/glue/src/tvix_store_io.rs
+++ b/tvix/glue/src/tvix_store_io.rs
@@ -23,7 +23,7 @@ use tvix_castore::{
     directoryservice::{self, DirectoryService},
     Node,
 };
-use tvix_store::{pathinfoservice::PathInfoService, proto::PathInfo};
+use tvix_store::pathinfoservice::{PathInfo, PathInfoService};
 
 use crate::fetchers::Fetcher;
 use crate::known_paths::KnownPaths;
@@ -119,23 +119,8 @@ impl TvixStoreIO {
             .get(*store_path.digest())
             .await?
         {
-            // if we have a PathInfo, we know there will be a root_node (due to validation)
             // TODO: use stricter typed BuildRequest here.
-            Some(path_info) => {
-                let (name, node) = path_info
-                    .node
-                    .expect("no node")
-                    .into_name_and_node()
-                    .expect("invalid node");
-
-                assert_eq!(
-                    store_path.to_string().as_bytes(),
-                    name.as_ref(),
-                    "returned node basename must match requested store path"
-                );
-
-                node
-            }
+            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).
@@ -336,47 +321,37 @@ impl TvixStoreIO {
 
                             // assemble the PathInfo to persist
                             let path_info = PathInfo {
-                                node: Some(tvix_castore::proto::Node::from_name_and_node(
-                                    drv_output
-                                        .1
-                                        .path
-                                        .as_ref()
-                                        .ok_or(std::io::Error::new(
-                                            std::io::ErrorKind::Other,
-                                            "missing output store path",
-                                        ))?
-                                        .to_string()
-                                        .into(),
-                                    output_node,
-                                )),
+                                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(|path| Bytes::from(path.digest().as_slice().to_vec()))
+                                    .map(|s| (**s).to_owned())
                                     .collect(),
-                                narinfo: Some(tvix_store::proto::NarInfo {
-                                    nar_size,
-                                    nar_sha256: Bytes::from(nar_sha256.to_vec()),
-                                    signatures: vec![],
-                                    reference_names: output_needles
-                                        .iter()
-                                        .map(|path| path.to_string())
-                                        .collect(),
-                                    deriver: Some(tvix_store::proto::StorePath {
-                                        name: drv_path
+                                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))
                                 }),
                             };
 
@@ -421,8 +396,7 @@ impl TvixStoreIO {
     ) -> io::Result<(PathInfo, NixHash, StorePathRef<'a>)> {
         // 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.
+        // because the [PathInfo] needs to contain nar_{sha256,size}.
         let (nar_size, nar_sha256) = self
             .nar_calculation_service
             .as_ref()
@@ -431,7 +405,7 @@ impl TvixStoreIO {
 
         // 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(
+            nix_compat::store_path::build_ca_path(name, ca, Vec::<&str>::new(), false).map_err(
                 |_| {
                     std::io::Error::new(
                         std::io::ErrorKind::InvalidData,
@@ -446,8 +420,8 @@ impl TvixStoreIO {
         let path_info = tvix_store::import::derive_nar_ca_path_info(
             nar_size,
             nar_sha256,
-            Some(ca),
-            output_path.to_string().into(),
+            Some(ca.clone()),
+            output_path.to_owned(),
             root_node,
         );