gix-error conversion batch 1

[Byron]

Batch 1 Migration Complete

11 crates migrated from thiserror to gix-error, in 11 commits:
┌────────────────┬───────────────────────────────────────────────────────┬─────────────────────────────────────────────────────────────────────────┐
│     Crate      │                 Error types replaced                  │                            Downstream fixes                             │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-bitmap     │ 1 (ewah::decode::Error)                               │ none                                                                    │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-quote      │ 1 (ansi_c::undo::Error)                               │ none                                                                    │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-mailmap    │ 1 (parse::Error)                                      │ none                                                                    │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-fs         │ 1 (to_normal_path_components::Error)                  │ none                                                                    │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-lock       │ 1 (acquire::Error)                                    │ gix-testtools                                                           │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-path       │ 2 (relative_path::Error, realpath::Error)             │ gix-ref                                                                 │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-packetline │ 3 (encode::Error, decode::Error, decode::band::Error) │ none                                                                    │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-attributes │ 2 (name::Error, parse::Error)                         │ gix-pathspec                                                            │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-url        │ 3 (parse::Error, UrlParseError, expand_path::Error)   │ gix-transport, gix                                                      │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-hash       │ 7 (all error types)                                   │ gix-object, gix-pack, gix-odb, gix-index, gix-status, gix-protocol, gix │
├────────────────┼───────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┤
│ gix-features   │ 3 (DecompressError, CompressError, inflate::Error)    │ (included in gix-hash downstream)                                       │
└────────────────┴───────────────────────────────────────────────────────┴─────────────────────────────────────────────────────────────────────────┘
Verification: cargo check -p gix passes, all 21 test suites across the 11 crates pass with 0 failures.

Tasks

• fixup commits with correct authorship
• thorough review

[Copilot]

Pull request overview

This PR migrates 11 plumbing crates from thiserror to gix-error, implementing the project's error handling standardization strategy. The migration replaces enum-based error types with gix_error::Exn and uses message-based error construction for better composability and reduced boilerplate.

Changes:

• Replaces thiserror enums with gix_error::Exn<gix_error::Message> or gix_error::ValidationError
• Updates error construction to use message!() and raise() patterns
• Adjusts downstream crates to handle new error types via .into_error() conversions
• Replaces deprecated #[allow(missing_docs)] with #[expect(missing_docs)] throughout

Reviewed changes

Copilot reviewed 299 out of 349 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
gix-bitmap/src/ewah.rs	Converts EWAH decode error from thiserror enum to gix-error ValidationError
gix-quote/src/ansi_c.rs	Replaces ansi_c undo error enum with Exn
gix-mailmap/src/parse.rs	Converts mailmap parse errors to ValidationError
gix-fs/src/stack.rs	Updates path component error to ValidationError
gix-lock/src/acquire.rs	Migrates lock acquisition errors to Exn
gix-path/src/relative_path.rs	Converts RelativePath error to Exn
gix-path/src/realpath.rs	Replaces realpath error enum with Exn
gix-packetline/*	Converts encode/decode errors to gix-error types
gix-attributes/src/parse.rs	Migrates attribute parse errors to Exn
gix-url/src/expand_path.rs	Converts expand_path error to Exn
gix-hash/src/*	Replaces all hash-related errors with gix-error types
gix-features/src/zlib/*	Converts compression/decompression errors to Exn
gix/*	Updates downstream consumers to handle new error types

[Copilot]

The error message assertion uses contains() which is fragile - it could break if the error message wording changes. Consider using a more specific error type check or pattern matching instead of string comparison.

Suggested change

	assert!(
	err.to_string().contains("does not specify a path to a repository"),
	assert_eq!(
	"does not specify a path to a repository",
	err.to_string(),

[Copilot]

The error message exposes the full digest of a collision attack. Consider whether this information should be included in user-facing error messages, as it might aid attackers in understanding detection mechanisms.

Suggested change

	CollisionResult::Collision(digest) => Err(gix_error::message!(
	"Detected SHA-1 collision attack with digest {}",
	crate::ObjectId::Sha1(digest.into())
	)),
	CollisionResult::Collision(_digest) => Err(gix_error::message(
	"Detected SHA-1 collision attack"
	)),

[EliahKagan]

This Copilot code review suggestion makes no sense.

• SHA-1 collision detection mechanisms are not secret.
• If such a mechanism were secret, it would most likely be inadequately studied, unsafe for use, and ineffective.
• We detect the same collisions Git detects; if we didn't, that would violate users' security and compatibility assumptions.
• Gitoxide is free open source software.
• Gitoxide may be used in closed source software, but the library code that detects collisions is still free open soruce software.
• Attackers don't need help finding out which of the collisions that they have themselves produced are being detected. They already know.
• If somehow they didn't already know, they can attempt one collision at a time to find out.
• Omitting this information would directly prevent victims of an attack from knowing essential information that is already available to attackers.

[Byron]

I didn't even read them yet, as I am working my way through this manually anyway. But it's interesting to see what it makes up sometimes.

[Copilot]

In benchmark code, adding error context via or_raise could impact performance measurements. Consider using direct error propagation with ? to minimize overhead in performance-critical paths.

[Copilot]

The test helper now uses starts_with() instead of exact equality, which is more flexible but may hide issues where error messages have changed completely. Consider documenting why prefix matching is sufficient for these tests.

[Copilot]

Line 19 parses the URL and converts to error, but line 22 passes the raw repo_url string to prepare_clone. The parsed URL is only used for printing, making the parse operation redundant. Consider removing the redundant parse or using the parsed URL if possible.

Suggested change

	let url = gix::url::parse(repo_url.to_str().unwrap().into()).map_err(gix_error::Exn::into_error)?;
	println!("Url: {:?}", url.to_bstring());