Add hex_to_id_sha1_only, use in SHA-1 only tests

[Christoph Rüßler (cruessler)]

This is a follow-up to #2578. There’s some tests in gix/tests that are SHA-1 only in that they contain hard-coded SHA-1 hashes and don’t have a corresponding version for SHA-256 hashes. They still share the same hex_to_id function that returns a SHA-1 or SHA-256 hash, based on gix_testtools::object_hash. The behaviour of hex_to_id diverges from other instances of hex_to_id in other crates: in gix/tests, hex_to_id silently returns the SHA-1 has that was passed in when there’s no SHA-256 hash in the mapping while in other crates it is a hard error when the SHA-1 hash can’t be found in the mapping. This PR introduces a separate hex_to_id_sha1_only that keeps the fallback behaviour, so that hex_to_id can be changed to mirror hex_to_id in other crates.

[Copilot]

Pull request overview

This PR refines SHA-1 vs SHA-256 handling in the gix integration tests by separating “hash mapping aware” ID conversion from “SHA-1 literal” ID conversion, preparing gix/tests for stricter SHA-256 fixture runs.

Changes:

• Tighten hex_to_id() so SHA-256 fixture mode requires a SHA-1→SHA-256 mapping entry (no silent fallback).
• Add hex_to_id_sha1_only() for tests that intentionally hard-code SHA-1 object IDs.
• Update SHA-1-only revision-spec and repository tests to use hex_to_id_sha1_only().

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
gix/tests/gix/util.rs	Makes hex_to_id() strict in SHA-256 mode and adds hex_to_id_sha1_only() for SHA-1-only tests.
gix/tests/gix/revision/spec/from_bytes/traverse.rs	Switches expected IDs to hex_to_id_sha1_only() in SHA-1-only traversal assertions.
gix/tests/gix/revision/spec/from_bytes/regex.rs	Uses hex_to_id_sha1_only() for SHA-1-only regex revspec expectations.
gix/tests/gix/revision/spec/from_bytes/reflog.rs	Uses hex_to_id_sha1_only() for reflog-based SHA-1-only expectations.
gix/tests/gix/revision/spec/from_bytes/peel.rs	Uses hex_to_id_sha1_only() for peel tests with hard-coded SHA-1 IDs.
gix/tests/gix/revision/spec/from_bytes/mod.rs	Updates module-level imports/usages to prefer hex_to_id_sha1_only() where appropriate.
gix/tests/gix/revision/spec/from_bytes/ambiguous.rs	Moves hard-coded SHA-1 expectations to hex_to_id_sha1_only().
gix/tests/gix/repository/mod.rs	Updates SHA-1-only revision parsing expectations to hex_to_id_sha1_only().

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[Sebastian Thiel (Byron)]

Thanks a lot, much appreciated!

[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

gix/tests/gix/util.rs:173

• hex_to_id_sha1_only() is documented/named as “SHA-1 only”, but it currently just forwards to ObjectId::from_hex(), which will also accept 64-hex inputs and yield a SHA-256 id. If this helper is meant to enforce SHA-1, consider asserting hex.len() == 40 (and adjusting the expect message to “40 hex chars” rather than “40 bytes”).

/// Convert a hexadecimal hash into its corresponding `ObjectId` or _panic_.
///
/// This does *not* take `GIX_TEST_FIXTURE_HASH` into account, so it does not map SHA-1 hashes to
/// SHA-256 hashes. Use this for tests that don't need a mapping.
pub fn hex_to_id_sha1_only(hex: &str) -> gix_hash::ObjectId {
    gix_hash::ObjectId::from_hex(hex.as_bytes()).expect("40 bytes hex")
}