fix(core): remove invalid diff.external override by urielefrenvirtusa · Pull Request #29467 · google-gemini/gemini-cli

urielefrenvirtusa · 2026-09-23T19:10:10Z

Summary

Removes the invalid diff.external configuration override from ShellExecutionService and gitUtils.getSafeGitEnv(), resolving fatal cannot spawn : No such file or directory / error: cannot run : No such file or directory errors when executing Git diff commands in the execution sandbox.

Details

In PR #28792, environment overrides were added to isolate Git operations. Among these, diff.external was mapped to an empty string ("") under the assumption that an empty value would disable external diffing (similar to credential.helper = "" resetting helper lists).

However, in Git's internal diff engine (diff.c / run_external_diff), any non-NULL string configured for diff.external is treated as an executable command path. When differences are computed, Git attempts to invoke "", failing via execvp or CreateProcess with ENOENT.

Changes in this PR:

Removed ['diff.external', ''] from defaultGitOverrides in packages/core/src/services/shellExecutionService.ts.
Removed GIT_CONFIG_KEY_7: 'diff.external' and GIT_CONFIG_VALUE_7: '' from packages/core/src/utils/gitUtils.ts, adjusting GIT_CONFIG_COUNT from 8 to 7.
Updated test expectations in packages/core/src/services/shellExecutionService.test.ts.
Added comprehensive unit tests in packages/core/src/utils/gitUtils.test.ts covering safe environment variables, absence of diff.external, and end-to-end git diff operations on modified repositories and commits.

Related Issues

Fixes #28928

How to Validate

Run the targeted unit test suite:

npm test -w @google/gemini-cli-core -- src/utils/gitUtils.test.ts src/services/shellExecutionService.test.ts

Verify all 91 tests in the suites pass.

Manually test running git diff on a modified file with getSafeGitEnv:

node -e "
const { spawnSync } = require('child_process');
const { getSafeGitEnv } = require('./packages/core/dist/src/utils/gitUtils.js');
const res = spawnSync('git', ['diff'], { env: getSafeGitEnv() });
console.log('Exit status:', res.status);
"

Confirm exit status is 0 without external diff spawn errors.

Pre-Merge Checklist

Configuring diff.external to an empty string ("") causes Git to attempt to execute "" as an external diff tool, which fails with "cannot spawn : No such file or directory" (Windows) or "error: cannot run : No such file or directory" (POSIX) whenever differences exist between trees or in the working tree. Removes diff.external from defaultGitOverrides in ShellExecutionService and from getSafeGitEnv in gitUtils, restoring Git's built-in diff engine, and adds comprehensive test coverage for gitUtils. Fixes google-gemini#28928

gemini-code-assist · 2026-09-23T19:10:22Z

Summary of Changes

Hello, 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 addresses a critical issue where Git operations failed due to an incorrectly configured 'diff.external' environment variable. By removing this invalid override, the system now correctly executes Git commands without attempting to invoke non-existent external diff tools. The changes include updates to core service configurations and the addition of robust unit tests to prevent future regressions in Git environment isolation.

Highlights

Removal of invalid Git configuration: Removed the 'diff.external' override from Git environment configurations, as setting it to an empty string causes Git to attempt to execute an invalid command.
Updated Git environment security settings: Adjusted 'GIT_CONFIG_COUNT' and removed the associated key-value pairs in 'gitUtils' and 'shellExecutionService' to reflect the removal of the external diff override.
Enhanced test coverage: Added comprehensive unit tests in 'gitUtils.test.ts' to verify safe environment variable handling and ensure 'git diff' operations function correctly in isolated environments.

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github-actions · 2026-09-23T19:10:32Z

📊 PR Size: size/L

Lines changed: 254
Additions: +246
Deletions: -8
Files changed: 4

urielefrenvirtusa · 2026-09-23T19:11:31Z

/Gemini review

gemini-code-assist

Code Review

This pull request removes the diff.external override from the default Git security configuration across ShellExecutionService and gitUtils. This change prevents Git from attempting to execute an empty string as an external diff tool, which would otherwise fail. Additionally, a comprehensive test suite has been introduced in packages/core/src/utils/gitUtils.test.ts to validate the behavior of Git utility functions, including environment sanitization and repository detection. There are no review comments, and I have no feedback to provide.

gemini-code-assist

Code Review

This pull request removes the diff.external security override from the default Git environment configuration in both ShellExecutionService and gitUtils to prevent Git from failing when attempting to execute an empty string as an external diff tool. Additionally, the PR updates the associated unit tests to reflect the reduced count of security overrides and introduces a comprehensive new test suite for gitUtils.ts. There are no review comments to address.

…s CI Use fs.realpath to resolve macOS symlinked /var paths and Windows 8.3 short filename aliases in absolute git dir assertions.

urielefrenvirtusa · 2026-09-24T16:32:27Z

/gemini review

gemini-code-assist

Code Review

This pull request removes the 'diff.external' security override from the default Git configuration environment variables in both shellExecutionService.ts and gitUtils.ts, updating the respective configuration counts. It also introduces a comprehensive test suite for gitUtils.ts. The review feedback suggests improving the test for filesystem errors by asserting that the existsSync spy was actually called, ensuring the error-handling path is correctly exercised.

Assert existsSyncSpy was called to ensure the error-handling path in isGitRepository and findGitRoot is exercised.

urielefrenvirtusa · 2026-09-24T16:44:44Z

/Gemini review

gemini-code-assist

Code Review

This pull request removes the diff.external override from the default Git security configurations to prevent execution failures during git diff operations, updating the environment configuration count from 8 to 7. It also introduces a new test suite for Git utilities. The reviewer feedback suggests replacing git init -b main with git init in the tests to ensure compatibility with Git versions older than 2.28.0.

…tibility Avoid -b option in git init calls within gitUtils tests to ensure compatibility with Git versions pre-2.28.0.

urielefrenvirtusa · 2026-09-24T17:01:06Z

/Gemini review

gemini-code-assist

Code Review

This pull request removes the diff.external override from the default Git environment configuration in both ShellExecutionService and gitUtils to prevent Git execution failures. It also introduces a new comprehensive test suite in gitUtils.test.ts and updates existing tests to reflect the updated configuration count. I have no feedback to provide as there are no review comments.

urielefrenvirtusa requested a review from a team as a code owner September 23, 2026 19:10

github-actions Bot added the size/m A medium sized PR label Sep 23, 2026

gemini-code-assist Bot reviewed Sep 23, 2026

View reviewed changes

gemini-cli Bot added priority/p1 Important and should be addressed in the near term. area/core Issues related to User Interface, OS Support, Core Functionality labels Sep 23, 2026

Merge branch 'main' into b_561553835

bc0527f

github-actions Bot mentioned this pull request Sep 23, 2026

📊 AI CLI 工具社区动态日报 2026-09-24 litang9/big_model_radar#443

Open

urielefrenvirtusa added 2 commits September 24, 2026 16:28

test(core): canonicalize paths in gitUtils tests for macOS and Window…

a2bdd7d

…s CI Use fs.realpath to resolve macOS symlinked /var paths and Windows 8.3 short filename aliases in absolute git dir assertions.

Merge branch 'main' into b_561553835

982418d

gemini-code-assist Bot reviewed Sep 24, 2026

View reviewed changes

Comment thread packages/core/src/utils/gitUtils.test.ts Outdated

test(core): verify existsSync spy is called in filesystem error test

2e3376c

Assert existsSyncSpy was called to ensure the error-handling path in isGitRepository and findGitRoot is exercised.

github-actions Bot added the size/l A large sized PR label Sep 24, 2026

gemini-code-assist Bot reviewed Sep 24, 2026

View reviewed changes

Comment thread packages/core/src/utils/gitUtils.test.ts Outdated

Comment thread packages/core/src/utils/gitUtils.test.ts Outdated

Comment thread packages/core/src/utils/gitUtils.test.ts Outdated

Comment thread packages/core/src/utils/gitUtils.test.ts Outdated

test(core): use standard git init without -b flag for backwards compa…

65bcf6b

…tibility Avoid -b option in git init calls within gitUtils tests to ensure compatibility with Git versions pre-2.28.0.

gemini-code-assist Bot reviewed Sep 24, 2026

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DavidAPierce approved these changes Sep 24, 2026

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DavidAPierce enabled auto-merge September 24, 2026 17:43

DavidAPierce added this pull request to the merge queue Sep 24, 2026

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Sep 24, 2026

DavidAPierce added this pull request to the merge queue Sep 25, 2026

Merged via the queue into google-gemini:main with commit 562f036 Sep 25, 2026
50 of 53 checks passed

urielefrenvirtusa deleted the b_561553835 branch September 25, 2026 15:53

This was referenced Sep 25, 2026

📊 AI CLI 工具社区动态日报 2026-09-26 litang9/big_model_radar#453

Open

📊 AI CLI 工具社区动态日报 2026-09-26 96loveslife/big_model_radar#548

Open

📊 AI CLI 工具社区动态日报 2026-09-27 litang9/big_model_radar#458

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urielefrenvirtusa commented Sep 23, 2026

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