feat!: add `hash_kind` to `TreeRefIter` and `Data` by cruessler · Pull Request #2497 · GitoxideLabs/gitoxide

Christoph Rüßler (cruessler) · 2026-03-31T18:55:39Z

This PR is an attempt at making the hash length in gix_object::tree::ref_iter::decode depend on the decoded tree’s hash’s size. Previously, it was hardcoded to 20 which is only correct for SHA1, but not for SHA256.

There were quite a few follow-up changes as TreeRef::from_bytes as well as TreeRefIter::from_bytes now take hash_kind as an argument. Also, since TreeRef can be instantiated in Data::decode, Data now also has to carry hash_kind. Another option that I didn’t explore would have been to add hash_kind as an argument to Data::decode.

Update 2026-04-04: I changed the initial addition of hash_len to hash_kind. Tests are now passing, with the exception of the fuzzer having found an issue.

Review Tasks

fix CI and cleanup history
review
refactor

Sebastian Thiel (Byron)

Thanks a lot! I think it's great to see that overall, passing the hash kind through isn't crazy. I also left a few comments which I hope can lead to a small direction change.

Christoph Rüßler (cruessler) · 2026-04-04T09:25:38Z

Sebastian Thiel (@Byron) I made some changes based on your feedback. The PR contains a lot of small commits now, feel free to shuffle them around as you see fit!

The fuzzer seems to have found something, though at first sight, I wasn’t sure what to make of that finding. I’ll try figuring out what this is about, but maybe you’re more familiar with it and can quickly trace it back to one of my changes.

I added one TODO(SHA256) in gix-diff-tests. I plan on addressing it in the follow-up PR that makes gix-diff-tests run with SHA256 (we don’t do that yet).

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- fix fuzz test - document `hash_kind` parameter - minor refactors Co-authored-by: Sebastian Thiel <sebastian.thiel@icloud.com>

Co-authored-by: Sebastian Thiel <sebastian.thiel@icloud.com>

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Pull request overview

This PR updates gitoxide’s object decoding to correctly handle non-SHA1 repositories by making tree entry hash sizes depend on the decoded tree’s hash kind (e.g., 32 bytes for SHA-256 instead of a hardcoded 20). This propagates hash_kind through core borrowed-object APIs (TreeRefIter, TreeRef::from_bytes, Data, and ObjectRef parsing) and updates downstream callers and tests accordingly.

Changes:

Add hash_kind to gix_object::TreeRefIter and gix_object::Data, and thread it through tree decoding/iteration and object decoding entrypoints.
Update call sites across gix, gix-pack, gix-odb, gix-ref, gix-merge, and gitoxide-core to provide the correct hash kind.
Extend/adjust tests and fixtures (including SHA-256 fixtures) and make diff test snapshots hash-agnostic.

Reviewed changes

Copilot reviewed 46 out of 50 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
justfile	Runs `gix-diff-tests` with SHA-256 fixtures in unit-tests recipe.
gix/tests/gix/object/tree/mod.rs	Adds regression test ensuring tree decode uses the tree id’s hash kind.
gix/src/repository/impls.rs	Populates `hash_kind` when producing empty-tree `Data`.
gix/src/repository/diff.rs	Passes tree id hash kind into `TreeRefIter::from_bytes()` for diffing.
gix/src/object/tree/traverse.rs	Passes root tree id hash kind into traversal iterator.
gix/src/object/tree/mod.rs	Uses tree id hash kind for decode/iteration and for `Data::new()` during lookups.
gix/src/object/tree/diff/for_each.rs	Passes per-tree hash kind into diff iterator construction.
gix/src/object/mod.rs	Constructs `gix_object::Data` with id-derived hash kind for decoding helpers.
gix-traverse/src/tree/depthfirst.rs	Supplies hash kind to `TreeRefIter::from_bytes()` during traversal.
gix-ref/tests/refs/file/mod.rs	Test `Find` impl now sets `Data.hash_kind` from requested id.
gix-ref/src/store/file/raw_ext.rs	Adjusts `Data` destructuring for added `hash_kind` field.
gix-pack/tests/pack/data/input.rs	Test objects and `Find` impl now set `hash_kind` from env/id.
gix-pack/src/index/verify.rs	Uses new `ObjectRef::from_bytes(data, kind, hash_kind)` signature.
gix-pack/src/index/traverse/mod.rs	Builds `Data` with id-derived hash kind before checksum verification.
gix-pack/src/data/output/count/objects/mod.rs	Uses `obj.hash_kind` when iterating trees.
gix-pack/src/bundle/find.rs	Sets `Data.hash_kind` from pack object hash.
gix-odb/src/store_impls/loose/find.rs	Sets `Data.hash_kind` from requested id.
gix-odb/src/store_impls/dynamic/find.rs	Sets `Data.hash_kind` from pack object hash in dynamic store.
gix-odb/src/memory.rs	Sets `Data.hash_kind` from requested id.
gix-odb/src/cache.rs	Creates cached `Data` with `id.kind()` as hash kind.
gix-object/tests/object/tree/iter.rs	Updates tree iterator tests to supply hash kind (from env).
gix-object/tests/object/tree/from_bytes.rs	Updates tree decode tests to supply hash kind (from env).
gix-object/tests/object/tree/entries.rs	Updates tree parsing tests to supply hash kind (from env).
gix-object/tests/object/tree/editor.rs	Test `Find` impl now sets `Data.hash_kind` from requested id.
gix-object/tests/object/tag.rs	Adds test for invalid target id length in tag parsing.
gix-object/tests/object/object_ref.rs	Updates `ObjectRef::from_loose()` tests for new signature.
gix-object/tests/object/encode.rs	Adds hash-kind-aware roundtrip macro and updates tree roundtrip.
gix-object/tests/object/commit/mod.rs	Adds test for invalid object id length in commit parsing.
gix-object/src/tree/ref_iter.rs	Core change: `TreeRefIter` carries hash kind; tree decoding uses hash-len parameter.
gix-object/src/parse.rs	Tightens `hex_hash` parsing to only accept lengths matching enabled hash kinds.
gix-object/src/object/mod.rs	`ObjectRef::from_loose/from_bytes` now require hash kind to decode trees correctly.
gix-object/src/lib.rs	Updates docs and adds `hash_kind` fields to `TreeRefIter` and `Data` structs.
gix-object/src/data.rs	`Data::new()` signature changed to include hash kind; tree decode uses it.
gix-object/fuzz/fuzz_targets/fuzz_tree.rs	Fuzzes tree decoding for both SHA-1 and SHA-256 hash kinds.
gix-object/fuzz/Cargo.toml	Enables `gix-hash` sha1+sha256 in fuzz crate dependencies.
gix-object/benches/edit_tree.rs	Bench `Find` impl now sets `Data.hash_kind`.
gix-object/benches/decode_objects.rs	Bench uses env-selected hash kind for tree parsing benchmarks.
gix-merge/tests/merge/blob/mod.rs	Test `Find` impl now sets `Data.hash_kind` from requested id.
gix-merge/src/tree/function.rs	Supplies base tree hash kind to `TreeRefIter::from_bytes()`.
gix-diff/tests/fixtures/generated-archives/make_blob_repo_sha256.tar	Adds SHA-256 fixture archive for diff tests.
gix-diff/tests/fixtures/generated-archives/.gitignore	Ignores newly added SHA-256 generated fixture tar.
gix-diff/tests/diff/tree_with_rewrites.rs	Makes snapshots hash-agnostic and opens ODB with correct object hash kind.
gix-diff/tests/diff/tree.rs	Uses hash-agnostic assertions and shared ODB-opening helper.
gix-diff/tests/diff/main.rs	Adds fixture hash-kind detection, ODB open helper, and snapshot normalization utilities.
gix-diff/tests/diff/index.rs	Updates snapshots/assertions and expected ids for SHA-1 vs SHA-256 fixtures.
gix-diff/tests/Cargo.toml	Enables `gix-hash` sha1+sha256 features for diff test crate.
gitoxide-core/src/index/checkout.rs	Ensures `Data.hash_kind` is set in custom `Find` implementations.

Sebastian Thiel (Byron) · 2026-04-20T06:17:56Z

Thanks so much!

Please note that I accidentally added gix-diff SHA-256 tests, please double-check if I am missing something obvious.

Christoph Rüßler (cruessler) · 2026-04-21T18:48:48Z

Thanks so much!

Please note that I accidentally added gix-diff SHA-256 tests, please double-check if I am missing something obvious.

No worries! I’ve created #2532 as a small follow-up.

Update call sites for gix 0.83's API: `SignatureRef::from_bytes` now returns a `Result` rather than an `Option` [1], and `TreeRefIter::from_bytes` takes the object hash kind [2]. The crate sets `default-features = false` on gix, so also enable the `sha1` feature, which `gix-hash` no longer enables by default [3]. For `TreeRefIter::from_bytes`, pass the hash kind of the tree id already in hand (`id.kind()`), matching how gitoxide's own tree API derives it. Make the `Item` size guard robust to the enabled hash features instead of asserting an absolute byte count. `gix::ObjectId` is a SHA-1/SHA-256 enum whose width depends on which `gix-hash` features are unified into the build; the gix-testtools dev-dependency enables `gix-hash/sha256` in test builds, widening it there but not in production. Bound only the part we own rather than the gix-controlled fields. [1]: GitoxideLabs/gitoxide@91c854e (GitoxideLabs/gitoxide#2546) [2]: GitoxideLabs/gitoxide@3b156e8 (GitoxideLabs/gitoxide#2497) [3]: GitoxideLabs/gitoxide@1019b42 (GitoxideLabs/gitoxide#2441) Co-authored-by: Eliah Kagan <degeneracypressure@gmail.com>

Update call sites for gix 0.83's API: `SignatureRef::from_bytes` now returns a `Result` rather than an `Option` [1], and `TreeRefIter::from_bytes` takes the object hash kind [2]. The crate sets `default-features = false` on gix, so also enable the `sha1` feature, which `gix-hash` no longer enables by default [3]. For `TreeRefIter::from_bytes`, pass the hash kind of the tree id already in hand (`id.kind()`), matching how gitoxide's own tree API derives it. Update the `Item` size guard from 200 to 240 bytes. The gix-testtools dev-dependency enables `gix-hash/sha256` in test builds (where this guard runs), so `gix::ObjectId` is its wider SHA-1/SHA-256 enum (33 bytes) and `Item` holds three of them; a production (sha1-only) build is ~200. [1]: GitoxideLabs/gitoxide@91c854e (GitoxideLabs/gitoxide#2546) [2]: GitoxideLabs/gitoxide@3b156e8 (GitoxideLabs/gitoxide#2497) [3]: GitoxideLabs/gitoxide@1019b42 (GitoxideLabs/gitoxide#2441) Co-authored-by: Eliah Kagan <degeneracypressure@gmail.com> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Update call sites for gix 0.83's API: `SignatureRef::from_bytes` now returns a `Result` rather than an `Option` [1], and `TreeRefIter::from_bytes` takes the object hash kind [2]. The crate sets `default-features = false` on gix, so also enable the `sha1` feature, which `gix-hash` no longer enables by default [3]. For `TreeRefIter::from_bytes`, pass the hash kind of the tree id already in hand (`id.kind()`), matching how gitoxide's own tree API derives it. Update the `Item` size guard from 200 to 240 bytes. The gix-testtools dev-dependency enables `gix-hash/sha256` in test builds (where this guard runs), so `gix::ObjectId` is its wider SHA-1/SHA-256 enum (33 bytes) and `Item` holds three of them; a production (sha1-only) build is ~200. [1]: GitoxideLabs/gitoxide#2546 [2]: GitoxideLabs/gitoxide@3b156e8 (GitoxideLabs/gitoxide#2497) [3]: GitoxideLabs/gitoxide@1019b42 (GitoxideLabs/gitoxide#2441) Co-authored-by: Eliah Kagan <degeneracypressure@gmail.com> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Update call sites for gix 0.83's API: `SignatureRef::from_bytes` now returns a `Result` rather than an `Option` [1], and `TreeRefIter::from_bytes` takes the object hash kind [2]. The crate sets `default-features = false` on gix, so also enable the `sha1` feature, which `gix-hash` no longer enables by default [3]. For `TreeRefIter::from_bytes`, pass the hash kind of the tree id already in hand (`id.kind()`), matching how gitoxide's own tree API derives it. Update the `Item` size guard from 200 to 240 bytes. The gix-testtools dev-dependency enables `gix-hash/sha256` in test builds (where this guard runs), so `gix::ObjectId` is its wider SHA-1/SHA-256 enum (33 bytes) and `Item` holds three of them; a production (sha1-only) build is ~200. [1]: GitoxideLabs/gitoxide@b060eb2, GitoxideLabs/gitoxide@91c854e (GitoxideLabs/gitoxide#2546) [2]: GitoxideLabs/gitoxide@3b156e8 (GitoxideLabs/gitoxide#2497) [3]: GitoxideLabs/gitoxide@1019b42 (GitoxideLabs/gitoxide#2441) Co-authored-by: Eliah Kagan <degeneracypressure@gmail.com> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Update call sites for gix 0.83's API: `SignatureRef::from_bytes` is no longer generic over the error type and returns a concrete-error `Result` [1], and `TreeRefIter::from_bytes` takes the object hash kind [2]. The crate sets `default-features = false` on gix, so also enable the `sha1` feature, which `gix-hash` no longer enables by default [3]. For `TreeRefIter::from_bytes`, pass the hash kind of the tree id already in hand (`id.kind()`), matching how gitoxide's own tree API derives it. Update the `Item` size guard from 200 to 240 bytes. The gix-testtools dev-dependency enables `gix-hash/sha256` in test builds (where this guard runs), so `gix::ObjectId` is its wider SHA-1/SHA-256 enum (33 bytes) and `Item` holds three of them; a production (sha1-only) build is ~200. [1]: GitoxideLabs/gitoxide@b060eb2, GitoxideLabs/gitoxide@91c854e (GitoxideLabs/gitoxide#2546) [2]: GitoxideLabs/gitoxide@3b156e8 (GitoxideLabs/gitoxide#2497) [3]: GitoxideLabs/gitoxide@1019b42 (GitoxideLabs/gitoxide#2441) Co-authored-by: Eliah Kagan <degeneracypressure@gmail.com> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Sebastian Thiel (Byron) reviewed Apr 4, 2026

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Comment thread gix-object/src/object/mod.rs Outdated

Comment thread gix-object/src/tree/ref_iter.rs Outdated

Comment thread gix-object/src/lib.rs Outdated

Comment thread gix-object/src/lib.rs Outdated

Christoph Rüßler (cruessler) changed the title ~~feat!: add hash_len to TreeRefIter and Data~~ feat!: add hash_kind to TreeRefIter and Data Apr 4, 2026

Christoph Rüßler (cruessler) marked this pull request as ready for review April 4, 2026 09:20

chatgpt-codex-connector Bot reviewed Apr 4, 2026

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Comment thread gix/src/object/tree/mod.rs Outdated

Sebastian Thiel (Byron) self-assigned this Apr 19, 2026

Sebastian Thiel (Byron) force-pushed the pass-hash-len-to-tree-ref-iter branch 2 times, most recently from 3586649 to 3430e49 Compare April 19, 2026 23:07

Sebastian Thiel (Byron) self-requested a review April 20, 2026 01:43

Christoph Rüßler (cruessler) and others added 4 commits April 20, 2026 11:57

feat!: add hash_kind to TreeRefIter and Data for SHA-256 support

3b156e8

adapt to changes in gix-object

6df1d55

review

d9b358b

- fix fuzz test - document `hash_kind` parameter - minor refactors Co-authored-by: Sebastian Thiel <sebastian.thiel@icloud.com>

Add SHA-256 suppoprt for gix-diff-tests crate

a9ed60e

Co-authored-by: Sebastian Thiel <sebastian.thiel@icloud.com>

Sebastian Thiel (Byron) force-pushed the pass-hash-len-to-tree-ref-iter branch from 22a23da to a9ed60e Compare April 20, 2026 05:57

Sebastian Thiel (Byron) requested a review from Copilot April 20, 2026 06:08

Copilot started reviewing on behalf of Sebastian Thiel (Byron) April 20, 2026 06:09 View session

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Sebastian Thiel (Byron) enabled auto-merge April 20, 2026 06:13

Sebastian Thiel (Byron) merged commit 7d50c30 into GitoxideLabs:main Apr 20, 2026
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Sebastian Thiel (Byron) mentioned this pull request Apr 20, 2026

SHA-256 tests for gix-object #2528

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Christoph Rüßler (cruessler) mentioned this pull request Apr 21, 2026

Use GIX_TEST_FIXTURE_HASH for gix-diff #2532

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feat!: add `hash_kind` to `TreeRefIter` and `Data`#2497

feat!: add `hash_kind` to `TreeRefIter` and `Data`#2497
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