feat: speed up finding changed files in commits by jskeet · Pull Request #2645 · googleapis/librarian

jskeet · 2025-10-22T10:13:35Z

We don't need the actual diffs between commits - only the names of the changed files. This massively improves performance of "release init".

While there may be other things we want to do in the future, this makes enough of a difference that we can probably hold off on larger changes (at least for the sake of performance).

Fixes #2634

We don't need the actual diffs between commits - only the names of the changed files. This massively improves performance of "release init". While there *may* be other things we want to do in the future, this makes enough of a difference that we can probably hold off on larger changes (at least for the sake of performance). Fixes googleapis#2634

gemini-code-assist · 2025-10-22T10:13:50Z

Summary of Changes

Hello @jskeet, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a significant performance enhancement by refining how changed files are detected within Git commits. Instead of computing comprehensive content diffs, the system now efficiently retrieves only the names of modified files. This targeted optimization is expected to dramatically speed up the "release init" command, addressing a known performance bottleneck without requiring more extensive architectural changes at this time.

Highlights

Performance Improvement: The method for identifying changed files between Git commits has been optimized to avoid generating full diffs, significantly boosting the performance of the "release init" process.
Git Operations Refinement: The underlying Git operation in ChangedFilesInCommit was switched from fromTree.Patch(toTree) to fromTree.Diff(toTree) to retrieve only file change metadata instead of full content differences.
File Name Extraction Logic: The logic for extracting and collecting changed file names has been refactored to correctly handle deletions, modifications, insertions, and renames based on the new Diff output structure.

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gemini-code-assist

Code Review

This pull request improves the performance of finding changed files in a commit by using fromTree.Diff instead of fromTree.Patch. This is a great optimization as it avoids calculating the full diff when only file names are needed.

I've found a small bug in the new implementation where it would add an empty string to the list of files for deletions. I've left a comment with a suggested fix. Otherwise, the change looks good.

internal/gitrepo/gitrepo.go

codecov · 2025-10-22T10:19:22Z

Codecov Report

❌ Patch coverage is 90.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 85.68%. Comparing base (88c4379) to head (511bbd4).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/gitrepo/gitrepo.go	90.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2645   +/-   ##
=======================================
  Coverage   85.68%   85.68%           
=======================================
  Files         108      108           
  Lines       11057    11059    +2     
=======================================
+ Hits         9474     9476    +2     
  Misses       1250     1250           
  Partials      333      333

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jskeet · 2025-10-22T11:03:23Z

/gemini review

gemini-code-assist

Code Review

This pull request enhances the performance of the release init process by optimizing the method for identifying changed files in commits. Instead of retrieving the actual diffs, the updated code now focuses solely on extracting the names of the modified files, leading to significant speed improvements. The changes include modifications to the ChangedFilesInCommit function in internal/gitrepo/gitrepo.go and the addition of new test cases in internal/gitrepo/gitrepo_test.go to cover deletion and renaming scenarios.

internal/gitrepo/gitrepo_test.go

internal/gitrepo/gitrepo.go

internal/gitrepo/gitrepo_test.go

codyoss

Thanks Jon, great find!

Librarian Version: v0.0.0-20251022154542-dd249212325d Language Image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/librarian-release-container:latest <details><summary>librarian: 0.5.0</summary> ## [0.5.0](v0.4.0...v0.5.0) (2025-10-22) ### Features * speed up finding changed files in commits (#2645) ([1060946](10609465)) * Can config dart `export` (#2641) ([97eacd2](97eacd29)) * minor whitespace and doc changes to the Dart templates (#2636) ([b3ac7b4](b3ac7b42)) * only generate libraries with changed APIs (#2618) ([82171be](82171bed)) * make extra modules public (#2622) ([2c94a53](2c94a53f)) * skip a GitHub release for a library (#2612) ([6258f4d](6258f4d1)) * allow skipping semver checks for rust-publish (#2584) ([739ce0d](739ce0d5)) * add ability to open pull request as a draft (#2604) ([c1f0285](c1f02859)) * capture discovery revision (#2605) ([14a1483](14a14830)) * Add conditional instrumentation to gRPC clients (#2594) ([3cc63b2](3cc63b22)) * add update-image CLI command (#2580) ([90e0f6e](90e0f6e5)) * Generate more samples for oneof main setters. (#2592) ([c55f3ce](c55f3ceb)) * Add documentation for generated service constructors (#2575) ([6a4aead](6a4aeade)) * disable some clippy warnings (#2567) ([9f51084](9f510842)) * Generate setter samples for oneof fields. (#2573) ([8c2416a](8c2416ab)) * add default Rust features option (#2562) ([892f42b](892f42b7)) * Include a correct URL for issues (#2570) ([10493ed](10493ed9)) * add ability to find the latest docker image SHA (#2539) ([62e80f1](62e80f19)) * add ability to checkout a repo at a certain commit (#2555) ([23b8ffe](23b8ffea)) * add onboarding PR body (#2552) ([e32719c](e32719cd)) ### Bug Fixes * associate bulk change to individual libraries (#2626) ([dd24921](dd249212)) * Allow `unnecessary_import`s (#2642) ([88c4379](88c43794)) * resolve issue where onboarded library can't be released (#2632) ([b300a4e](b300a4ea)) * resolve issue where commits cannot be fetched for new library (#2631) ([45652c0](45652c03)) * address a typo in the Message.ServicePlaceholder docs (#2616) ([82fda96](82fda96b)) * bad version bump edits (#2613) ([9902b1d](9902b1d5)) * use templates for update-image PR body (#2602) ([7309cad](7309cadd)) * populate configure command pr content (#2591) ([811eb8e](811eb8e2)) * shrink release PR size when there are bulk changes (#2585) ([bcb914a](bcb914ac)) * Fixes several issues with oneof main setter samples (#2589) ([e4958d0](e4958d00)) * resolve broken link in PR body (#2579) ([098c1d2](098c1d24)) * Remove double sample code blocks (#2582) ([6b10456](6b104567)) * change commit package (#2571) ([45ee48f](45ee48f0)) * show chores in release notes (#2544) ([88b62cc](88b62ccb)) * avoid work duplication when finding changes (#2558) ([0adeeac](0adeeac6)) * mangled method names and doc links (#2565) ([895dac9](895dac94)) ### Reverts * show chores in release notes (#2601) ([7e6740f](7e6740ff)) </details>

jskeet requested a review from codyoss October 22, 2025 10:13

jskeet requested a review from a team as a code owner October 22, 2025 10:13

gemini-code-assist bot reviewed Oct 22, 2025

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internal/gitrepo/gitrepo.go Outdated Show resolved Hide resolved

chore: fix reporting of deletions

511bbd4

gemini-code-assist bot reviewed Oct 22, 2025

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internal/gitrepo/gitrepo_test.go Show resolved Hide resolved

internal/gitrepo/gitrepo.go Show resolved Hide resolved

internal/gitrepo/gitrepo_test.go Show resolved Hide resolved

codyoss approved these changes Oct 22, 2025

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jskeet merged commit 1060946 into googleapis:main Oct 22, 2025
6 checks passed

jskeet deleted the speed-up-finding-changed-files branch October 22, 2025 13:43

cloud-sdk-librarian-robot mentioned this pull request Oct 22, 2025

chore: librarian release pull request: 20251022T180958Z #2653

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feat: speed up finding changed files in commits#2645

feat: speed up finding changed files in commits#2645
jskeet merged 2 commits intogoogleapis:mainfrom
jskeet:speed-up-finding-changed-files

jskeet commented Oct 22, 2025

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jskeet commented Oct 22, 2025

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