Respect git global ignore files (core.excludesFile) in source scanner

[Lukecele]

When scanning for source candidates, Oxide previously disabled git global ignore files via builder.git_global(false).

As noted in #15941, the intention was to prevent .gitignore files in parent directories outside of a git repository from taking effect, while keeping global ignore files configured in git working. However, calling git_global(false) on the walker had the unintended side effect of ignoring core.excludesFile (and $XDG_CONFIG_HOME/git/ignore) entirely.

This change enables builder.git_global(true) so that ignore patterns configured in Git's global configuration are respected during source scanning.

Fixes #20509

Test plan

• Added unit test respects_git_core_excludes_file in crates/oxide/tests/scanner.rs verifying that files matched by Git's core.excludesFile are skipped.
• Verified that all existing unit and scanner tests continue to pass.

[ci-all]

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Changes which files the scanner includes based on git configuration.

The PR appears safe to merge; no new actionable issues were identified.

_{Reviews (4) · Last reviewed commit: "test: isolate global git config environm..."}

[coderabbitai]

Navigate logical layers of code changes, visualize relationships, and explore their blast radius.

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Advanced

Run ID: 822cccba-7139-4f7e-afd9-85c93f7024e5

📥 Commits

Reviewing files that changed from the base of the PR and between 39cbde6 and 172a4c0.

📒 Files selected for processing (1)

• crates/oxide/tests/scanner.rs

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.

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Walkthrough

The excludes-file parser now accepts quoted core.excludesFile paths that contain spaces. The scanner now respects Git global ignore files. New tests check quoted-path parsing and verify that a globally excluded HTML file is omitted from scan results.

Priority: ➖ Normal

Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to 172a4

Repository-controlled test runs isolate the Git configuration change; no actionable merge-blocking risk remains.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 172a4

The change lets Git ignore settings affect which source files are scanned. Existing source-selection controls remain, and no security vulnerability was established. The remaining uncertainty is whether shared build environments allow untrusted parties to control those settings.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — A party controlling the scanner process's Git configuration or selected excludes file can influence discovery for sources subject to those rules. Exposure is bounded by that configuration authority and existing source selection; tenant-wide or cross-service attackability was not established.

Trust Boundaries and Controls

• observed — The PR activates an existing configuration-to-filesystem path in scanner discovery rather than adding a new configuration reader. Git settings become effective discovery policy, while the scanner's source-selection checks remain in place.

Resilience and Maintainability Implications

• observed — With the child marker absent, the test launches only itself in a child process and returns before mutating GIT_CONFIG_GLOBAL. Child termination contains that environment state on success or failure. A pre-existing marker skips isolation and leaves the mutation in the invoking test process; this limitation is test-only.

🚥 Pre-merge checks | ✅ 6

✅ Passed checks (6 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description directly explains the scanner change, its Git configuration behavior, the related issue, and the test plan.
Linked Issues check	✅ Passed	The changes directly address issue #20509 by respecting Git global ignore rules during source scanning.
Out of Scope Changes check	✅ Passed	The implementation and tests remain within the stated scope of enabling Git global ignore files and validating core.excludesFile behavior.
Title check	✅ Passed	The title clearly identifies the main change: respecting Git global ignore files in the source scanner.
Linked Issues check	✅ Passed	Issue [#20509] requires source scanning to skip files matched by Git core.excludesFile. create_walker now calls builder.git_global(true). The new respects_git_core_excludes_file test configure…
Out of Scope Changes check	✅ Passed	The changes stay within issue [#20509]. The scanner setting implements global Git ignore support. The parser change supports valid core.excludesFile paths required by that support. The test provides…

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[coderabbitai]

🧹 Nitpick comments (1)

crates/oxide/tests/scanner.rs (1)

2961-2961: 🩺 Stability & Availability | 🔵 Trivial | ⚡ Quick win

Synchronize the process-wide GIT_CONFIG_GLOBAL mutation.

GIT_CONFIG_GLOBAL is process-wide, and global Git-ignore handling reads it during Scanner::new. The configured pattern matches only ignored-by-global.html. The inspected concurrent scanner fixtures do not contain that basename, and their Git commands are only git init calls with ignored output. The race therefore does not currently change an asserted result or cause a command failure. It can affect a future scan that contains this basename. Isolate this test in a separate process or protect the mutation with a shared lock.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Advanced

Run ID: 7f764ba3-4601-4e02-b611-e93f5ae31d2d

📥 Commits

Reviewing files that changed from the base of the PR and between fa81d69 and 4f875f5.

📒 Files selected for processing (2)

• crates/oxide/src/scanner/mod.rs
• crates/oxide/tests/scanner.rs

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.

[Lukecele]

#20524 (review)

[Lukecele]

Hi maintainers, following up on this regression-test PR. It enables Git global ignore files during source scanning and adds coverage for core.excludesFile, addressing #20509. Greptile review is passing and the branch is mergeable; happy to adjust the implementation or test if there is any concern.