Add pre-commit hook to verify static analysis passes & format is correct by camsim99 · Pull Request #11941 · flutter/packages

camsim99 · 2026-06-18T19:33:51Z

Adds a pre-commit hook that you can install to verify that dart analyze --fatal-infos and the package format are correct when you make a call to git commit. Intended to ensure agents commit code that meets are quality standards.

Also makes the following updates the plugins tool:

Adds --run-on-staged-packages flag that allows the command to only run on files with staged changes. This flag cannot be run with any other flags that filter packages where the command runs (like --run-on-dirty-packages)
Adds optimization to the format tool to avoid invoking native tool chains to format when non-native files are modified

Miscellaneous notes:

script/githooks/bin/install_hooks.dart is the script to install the hook that devs would need to run to use it.
I modeled the new githooks directory like https://github.com/flutter/flutter/tree/master/engine/src/flutter/tools/githooks to make it easier for folks to add new hooks

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Code Review

This pull request introduces a new githooks Dart package to automate pre-commit checks, including formatting and static analysis, for staged files. The package includes an installation script, a pre-commit command runner, and associated unit tests. Review feedback highlights a potential infinite loop on Windows when locating the .git directory, raw ANSI escape sequences being printed without verifying terminal support, the use of loose any version constraints in pubspec.yaml, and redundant dead code in the test mocks.

camsim99 · 2026-06-26T17:12:46Z

+        print(diffResult.stderr);
+      }
+      // If we cannot determine the diff, abort pre-commit check.
+      return false;


I made this decision because I assume there must be a Git setup issue if this happens, but open to pushback if we think this could actually block valid commits.

reidbaker

Does the pr description still match what you have up for review?

reidbaker · 2026-06-29T15:09:17Z

+  Future<void> _formatJava(Iterable<String> files) async {
    final Iterable<String> javaFiles = _getPathsWithExtensions(files, <String>{'.java'});
    if (javaFiles.isNotEmpty) {
+      final String formatterPath = await _downloadJavaFormatterIfNecessary();


Nice change to only downloading if we need to format those languages.

reidbaker · 2026-06-29T15:18:01Z

+
    return files
        .where((File file) {
+          if (useDiff) {


quick double check that the conditions that are checked below like handFormattedExtension will still run as expected both when useDiff is true and false.

So as an example a hand formatted file that is edited will still be excluded
and a build/ file that is not edited will when useDiff is false will still be excluded.

Yes it still works as expected! Added tests.

reidbaker · 2026-06-29T15:44:50Z

+  /// Returns true if at least one staged file is located within a package directory
+  /// (under packages/ or third_party/packages/), false if there are none, or null
+  /// if the git command fails.
+  Future<bool?> _hasStagedPackages(Directory repoRoot) async {


I think this logic was moved to the format/package commands. If so consider removing it. If we add logic here to filter then it could be confusing if it diverges from what is in the other tooling.

The optimization was moved to the format/package commands but this is an additional optimization--when there are no relevant changes to have this hook check, let's skip calling into the plugins tool altogether. Calling into at all adds steps like checking package dependencies that we can skip if we aren't going to end up running the checks at all.

I don't see the risk of divergence being high, but if you're concerned we can remove it! I don't feel super strongly since we don't necessarily expect high human usage.

Ok in that case can you give me the situation and performance delta of this optimization? My understanding having not run it is that we are still spinning up dart and we are still filtering using the same git commands so I don't see how it could improve efficiency. Is there a step I am not seeing?

The most convincing evidence would be a common situation, maybe a merge conflict, and showing the difference is a multiple in speed.

I guess my larger concern is that the filtering should happen in one place unless we get a really large performance or ux gain and on my mind once we are in dart land we should be able to make the performance the same.

reidbaker · 2026-06-29T15:49:06Z

+      if (analyzeResult.stderr.toString().isNotEmpty) {
+        print(analyzeResult.stderr);
+      }
+      print('Static analysis failed. Please fix the errors listed above.');


Preference question for you. My gut says that all of our presubmits should fail, give the work around (--no-verify) then give the command to reproduce the failing condition. But it should not print everything that needs to be fixed. My logic here is that I don't want any complexity or logic in the presubmit that I can put someplace else and also if we make it a design expectation that the logic needs to live someplace else then that is more likely to happen.

I agree. Modified the failure messages to point to the command to run to find/fix the issues.

reidbaker

Let's measure the performance gain of the filter code in the pre submit command. If there is a large gain then this looks good. If not then let's remove that logic.

camsim99 · 2026-06-30T22:55:04Z

Let's measure the performance gain of the filter code in the pre submit command. If there is a large gain then this looks good. If not then let's remove that logic.

Quick test of with time git commit for empty commit:

	With optimization	Without
real	1.756s	6.005s
user	0.877s	5.925s
sys	0.563s	1.236s

reidbaker · 2026-06-30T22:59:52Z

Let's measure the performance gain of the filter code in the pre submit command. If there is a large gain then this looks good. If not then let's remove that logic.

Quick test of with time git commit for empty commit:

With optimization Without
real 1.756s 6.005s
user 0.877s 5.925s
sys 0.563s 1.236s

That is enough justification. Lets document that and move on.

reidbaker · 2026-07-01T15:06:25Z

Would you be willing to file a bug to have me/us investigate why the performance gap was so large.

auto-submit · 2026-07-01T17:27:19Z

autosubmit label was removed for flutter/packages/11941, because - The status or check suite Dashboard Checks has failed. Please fix the issues identified (or deflake) before re-applying this label.

camsim99 added 7 commits June 18, 2026 09:18

first pass

0a65ef8

rippling revisions

ccda0df

use plugin tool instead

09a89f2

-- debugging stuff

04253cc

fake commit

e078f24

test + command fix

d61f271

fake commit

a487e22

flutter-dashboard Bot added the CICD Run CI/CD label Jun 18, 2026

camsim99 added 11 commits June 22, 2026 10:06

try optimizing by cutting out native toolchains

85219e8

fake commit

021dd71

run dart analyze directly

4908982

undo fake commit

d05c928

run format and analyze directly on staged files

2d89dd8

fake commit

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use ANSI escape codes to erase status logs

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fake commit

f4eed3d

change emoji to runner

638ce34

undo fake commit

c19c8f3

make unit tests stricter

f8837ba

github-actions Bot removed the CICD Run CI/CD label Jun 22, 2026

camsim99 added 2 commits June 22, 2026 10:48

self review

352580c

expect args

a6a2a78

flutter-dashboard Bot added the CICD Run CI/CD label Jun 22, 2026

camsim99 added CICD Run CI/CD and removed CICD Run CI/CD labels Jun 22, 2026

camsim99 marked this pull request as ready for review June 22, 2026 17:58

gemini-code-assist Bot reviewed Jun 22, 2026

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camsim99 added 2 commits June 22, 2026 12:37

gemini review

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fix print

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camsim99 removed the CICD Run CI/CD label Jun 22, 2026

camsim99 added 2 commits June 26, 2026 09:55

clarify if test skipped

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little tweaks

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camsim99 commented Jun 26, 2026

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camsim99 added 2 commits June 26, 2026 12:09

self review

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test nits

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camsim99 requested a review from reidbaker June 26, 2026 19:27

camsim99 added the CICD Run CI/CD label Jun 26, 2026

reidbaker reviewed Jun 29, 2026

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address review

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camsim99 added the CICD Run CI/CD label Jun 29, 2026

camsim99 requested a review from reidbaker June 29, 2026 22:24

reidbaker reviewed Jun 30, 2026

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ignore

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reidbaker approved these changes Jul 1, 2026

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camsim99 mentioned this pull request Jul 1, 2026

[flutter_plugin_tools] Investigate and reduce overhead of execution in pre-commit hook flutter/flutter#188870

Open

add docs + todo for plugin tool overhead

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github-actions Bot removed the CICD Run CI/CD label Jul 1, 2026

camsim99 added CICD Run CI/CD autosubmit Merge PR when tree becomes green via auto submit App labels Jul 1, 2026

reidbaker approved these changes Jul 1, 2026

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auto-submit Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Jul 1, 2026

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