fix: filter false-positive "changed" files in incremental detection

[SutuSebastian]

Summary

• Incremental detection (getChangedFiles) reported uncommitted files as "changed" on every run, even when their content hash already matched the index — caused by git status --porcelain always including dirty working-tree files
• Now compares content hashes against the DB during detection, so only truly modified files enter the indexing pipeline
• Eliminates misleading Incremental: 1 changed logs and unnecessary read+hash work in indexFiles

Test plan

• bun run check (format, lint, typecheck, tests) all green
• Verified on external project (merchant-dashboard-v2, 1859 files, dirty working tree) — second consecutive run correctly shows 0 changed, 0 deleted / Index is up to date

Summary by CodeRabbit

Bug Fixes

• Resolved a false positive issue in incremental change detection where files with uncommitted modifications were repeatedly marked as changed even when their content remained unchanged. This fix improves the accuracy of file change identification and reduces unnecessary reprocessing during incremental indexing operations, enhancing overall indexing efficiency.

[changeset-bot]

🦋 Changeset detected

Latest commit: 39ef64f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@stainless-code/codemap	Patch

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 9de35510-caf4-42bf-b788-08bacbe43de8

📥 Commits

Reviewing files that changed from the base of the PR and between b5c2570 and 39ef64f.

📒 Files selected for processing (2)

• .changeset/fix-incremental-false-positive.md
• src/application/index-engine.ts

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📝 Walkthrough

Walkthrough

This change fixes incremental change detection in the indexing engine by modifying getChangedFiles to compare file content hashes against the index instead of relying on existence checks. This prevents unchanged files from being repeatedly marked as changed when the working tree contains uncommitted modifications.

Changes

Cohort / File(s)	Summary
Incremental Change Detection Fix src/application/index-engine.ts	Modified getChangedFiles to compute and compare file content hashes against existingHashes instead of using statSync existence checks. Only marks files as changed when content hash differs from index. Handles missing/unreadable files by placing them in deleted instead of changed.
Changelog Entry .changeset/fix-incremental-false-positive.md	Documents the fix for incremental change detection false positives in @stainless-code/codemap patch release.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A rabbit dug deep through the code,
Hash comparisons lightened the load,
No ghosts in the queue,
Just changes that's true,
Incremental runs skip the redundant road! 🌿✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and clearly describes the main fix: filtering false-positive changed files in incremental detection, which matches the core problem and solution in the changeset.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/incremental-false-positive-changed

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