fix: handle multi-line commit bodies in git log parsing by mikepenz · Pull Request #1553 · mikepenz/release-changelog-builder-action

mikepenz · 2026-04-10T10:09:58Z

Summary

Fixes crash when merge commits have multi-line bodies (e.g. Reviewed-on: / Reviewed-by: lines from Gitea) that caused TypeError: Cannot read properties of undefined (reading 'split')
Uses a null byte (%x00) record separator in the git log format string to correctly delimit commits, so newlines within the body don't split into bogus entries
Also fixes pipe characters (|) in commit bodies being truncated via rest destructuring

Test plan

Added __tests__/gitHelper.test.ts with 4 tests:
- Reproduces Failed to retrieve due to type error #1552 by proving the legacy parsing creates undefined subject fields from multi-line bodies
- Verifies the fix produces exactly 4 commits with all fields defined and multi-line body content preserved
- Verifies pipe characters in commit bodies are preserved
- Verifies empty git log output is handled gracefully
All existing tests pass

🤖 Generated with Claude Code

Use a null byte (%x00) record separator in git log format to correctly delimit commits, preventing multi-line bodies (e.g. merge commits with Reviewed-on/Reviewed-by lines) from being split into bogus commit entries with undefined fields. Fixes #1552 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

github-actions · 2026-04-10T10:10:39Z

	Tests	Passed ✅	Skipped	Failed
JUnit Test Report	71 ran	71 passed	0 skipped	0 failed

Test	Result
No test annotations available

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Pull request overview

Fixes getCommitsBetween parsing of git log output so merge commits with multi-line bodies (e.g., Reviewed-on: / Reviewed-by: lines) don’t create bogus “commit” entries and crash downstream processing.

Changes:

Updates git log pretty format to prefix each commit with a NUL (%x00) record separator.
Reworks parsing to split by NUL records and reassemble multi-line bodies (including | in bodies).
Adds a new Vitest suite covering multi-line bodies, | preservation, and empty output.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
`src/pr-collector/gitHelper.ts`	Uses NUL-delimited records and updated parsing to correctly handle multi-line commit bodies
`__tests__/gitHelper.test.ts`	Adds regression tests reproducing #1552 and verifying the new parsing behavior

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Copilot · 2026-04-10T10:13:48Z

      'log',
-      '--pretty=format:%H|%an|%ae|%aI|%s|%b',
+      '--pretty=format:%x00%H|%an|%ae|%aI|%s|%b',
      `${base}..${head}`
    ]
    if (includeOnlyPaths) {
      logArgs.push('--', ...includeOnlyPaths)
    }

    const logOutput = await this.execGit(logArgs)
-    const lines = logOutput.stdout.trim().split('\n').filter(line => line.trim() !== '')
-    const commits = lines.map(line => {
-      const [sha, authorName, authorEmail, authorDate, subject, body] = line.split('|')
+    // Split on null byte record separator to correctly handle multi-line commit bodies
+    const records = logOutput.stdout.split('\x00').filter(record => record.trim() !== '')
+    const commits = records.map(record => {
+      // The first line contains the pipe-delimited fields; remaining lines are part of the body
+      const [firstLine, ...remainingLines] = record.split('\n')
+      const [sha, authorName, authorEmail, authorDate, subject, ...bodyParts] = firstLine.split('|')
+      const firstBodyLine = bodyParts.join('|')


Parsing still relies on | as the field separator (firstLine.split('|')). While you re-join the body to preserve | in the body, any | in earlier fields (notably %s subject or %an author name) will still be mis-parsed and leak into the body. Consider switching the git pretty format to use a non-printable field separator (e.g., %x1f) in addition to the %x00 record separator, and split on that character for robust parsing of all fields.

Copilot · 2026-04-10T10:13:48Z

+    expect(bogusCommit.sha).toBe('Reviewed-by: chosen <chosen@example.com>')
+    expect(bogusCommit.subject).toBeUndefined()
+
+    // This is the exact crash from the issue: commit.subject.split('\n') throws TypeError


This test intentionally calls .split() on an undefined value to reproduce the historical crash, which can trigger TypeScript/IDE warnings. Consider making the intent explicit with a // @ts-expect-error (or casting bogusCommit.subject as any) on this line so future refactors don’t “fix” it accidentally.

Suggested change

// This is the exact crash from the issue: commit.subject.split('\n') throws TypeError

// This is the exact crash from the issue: commit.subject.split('\n') throws TypeError

// @ts-expect-error Intentionally calling .split() on undefined to reproduce the historical crash

Address review feedback: - Use %x1f (unit separator) as field delimiter instead of |, so pipe characters in author names or subjects don't corrupt parsing - Use trimEnd() instead of trim() to preserve leading whitespace in commit bodies - Recompile dist Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Node.js child_process.spawn() rejects arguments containing null bytes. Use git's own %x00 and %x1f pretty-format placeholders in the command argument, which git interprets at output time, producing the expected separator bytes in stdout without embedding them in the command args. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Copilot

Pull request overview

Copilot reviewed 2 out of 4 changed files in this pull request and generated 2 comments.

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Copilot · 2026-04-10T10:29:41Z

+  test('fixed parsing handles multi-line commit bodies and preserves their content', async () => {
+    const gitHelper = await createCommandManager('.')
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    vi.spyOn(gitHelper as any, 'execGit').mockResolvedValue({
+      stdout: buildFixedGitLog(),
+      exitCode: 0
+    })


The test constructs a real GitCommandManager via createCommandManager('.'), which calls io.which('git', true) during initialization. This makes the unit tests depend on git being present in PATH even though execGit is mocked. Consider mocking @actions/io's which (or exposing a lightweight constructor/factory for tests) so the tests stay hermetic and don't fail in minimal CI/dev environments.

Copilot · 2026-04-10T10:29:42Z

+    const FIELD_SEP = '\x1f' // unit separator — used for splitting output
+    const RECORD_SEP = '\x00' // null byte — used for splitting output
    const logArgs = [


FIELD_SEP/RECORD_SEP are created on every getCommitsBetween call; since they are constants, consider hoisting them to module scope (or static readonly) to avoid repetition and ensure the separators stay consistent if this format string changes elsewhere.

Copilot AI review requested due to automatic review settings April 10, 2026 10:09

Copilot started reviewing on behalf of mikepenz April 10, 2026 10:10

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Copilot AI reviewed Apr 10, 2026

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Mike Penz and others added 2 commits April 10, 2026 12:20

Copilot AI review requested due to automatic review settings April 10, 2026 10:24

mikepenz added the fix label Apr 10, 2026

mikepenz merged commit 5795a33 into develop Apr 10, 2026
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mikepenz deleted the fix/multiline-commit-body-parsing branch April 10, 2026 10:27

Copilot AI reviewed Apr 10, 2026

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fix: handle multi-line commit bodies in git log parsing - #1553

fix: handle multi-line commit bodies in git log parsing#1553
mikepenz merged 3 commits into
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fix/multiline-commit-body-parsing

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	// This is the exact crash from the issue: commit.subject.split('\n') throws TypeError
	// This is the exact crash from the issue: commit.subject.split('\n') throws TypeError
	// @ts-expect-error Intentionally calling .split() on undefined to reproduce the historical crash

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mikepenz commented Apr 10, 2026

Summary

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github-actions Bot commented Apr 10, 2026 •

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