fix(rules): ignore footer lines in body max length by puneetdixit200 · Pull Request #4813 · conventional-changelog/commitlint

puneetdixit200 · 2026-06-04T23:41:03Z

Summary

ignore trailing footer/trailer paragraphs when checking body line lengths
add a regression test for long Signed-off-by footer lines with short body lines

Fixes #4088

Tests

pnpm exec vitest run @commitlint/rules/src/body-max-line-length.test.ts @commitlint/rules/src/footer-max-line-length.test.ts
node scripts/check-no-focused-tests.js @commitlint/rules/src/body-max-line-length.test.ts
pnpm exec oxfmt --check --ignore-path .oxfmtignore @commitlint/rules/src/body-max-line-length.ts @commitlint/rules/src/body-max-line-length.test.ts
pnpm exec oxlint @commitlint/rules/src/body-max-line-length.ts @commitlint/rules/src/body-max-line-length.test.ts
git diff --check
pnpm build

qodo-code-review · 2026-06-04T23:41:23Z

Review Summary by Qodo

Ignore footer lines in body max length validation

🐞 Bug fix 🧪 Tests

Walkthroughs

Description

• Ignore footer/trailer lines when checking body max line length
• Add regression test for long footer lines with short body
• Implement trailer token detection to identify footer paragraphs
• Exclude trailing footers from body line length validation

Diagram

flowchart LR
  A["body-max-line-length rule"] -->|parse body and footer| B["withoutTrailingFooter function"]
  B -->|detect trailer tokens| C["TRAILER_TOKEN regex"]
  C -->|identify footer lines| D["remove footer from validation"]
  D -->|validate remaining body| E["maxLineLength check"]
  E -->|return result| F["pass/fail decision"]

File Changes

1. @commitlint/rules/src/body-max-line-length.ts 🐞 Bug fix +39/-2

Implement footer detection and exclusion logic

• Add withoutTrailingFooter() function to strip trailing footer paragraphs
• Implement TRAILER_TOKEN regex pattern to identify trailer lines
• Import toLines utility for line parsing
• Modify rule to exclude footers from body line length validation

@commitlint/rules/src/body-max-line-length.ts

2. @commitlint/rules/src/body-max-line-length.test.ts 🧪 Tests +8/-0

Add regression test for long footer lines
• Add longFooter test constant with long Signed-off-by line
• Add longFooter message test case combining short body with long footer
• Add regression test "with long footer should succeed"
@commitlint/rules/src/body-max-line-length.test.ts

qodo-code-review · 2026-06-04T23:41:24Z

Code Review by Qodo

🐞 Bugs (1) 📘 Rule violations (0) 📎 Requirement gaps (1)

Context used

✅ Tickets: 🎫 fix: `body-max-line-length` is not respecting `footer-max-line-length` and failing for long footers

1. TRAILER_TOKEN excludes valid footers 📎 Requirement gap ≡ Correctness

Description

withoutTrailingFooter() only treats the last paragraph as a footer if every line matches
TRAILER_TOKEN, but the regex requires a hyphenated token and will miss valid trailers like
Fixes:/Refs:/BREAKING CHANGE:. As a result, some footer lines can still be checked by
body-max-line-length, violating the requirement that footer line-length is not enforced by the
body rule.

Code

@commitlint/rules/src/body-max-line-length.ts[R5-33]

+const TRAILER_TOKEN = /^[A-Za-z0-9]+(?:-[A-Za-z0-9]+)+:\s\S/;
+
+function withoutTrailingFooter(body: string, footer?: string | null): string {
+	const footerStart = footer ? body.length - footer.length : -1;
+	const input =
+		footer &&
+		footerStart >= 0 &&
+		body.endsWith(footer) &&
+		(footerStart === 0 || body[footerStart - 1] === "\n")
+			? body.slice(0, footerStart).replace(/(\r?\n)+$/, "")
+			: body;
+
+	const lines = toLines(input);
+	let last = lines.length - 1;
+
+	while (last >= 0 && lines[last] === "") {
+		last--;
+	}
+
+	let first = last;
+
+	while (first >= 0 && lines[first] !== "") {
+		first--;
+	}
+
+	const footerLines = lines.slice(first + 1, last + 1);
+
+	if (footerLines.length === 0 || !footerLines.every((line) => TRAILER_TOKEN.test(line))) {
+		return input;

Evidence

The compliance rule requires that footer lines are not validated by body-max-line-length. The
added TRAILER_TOKEN regex only matches hyphenated trailer keys ((?:-[A-Za-z0-9]+)+), and
withoutTrailingFooter() returns the unmodified input when trailer lines don’t match it, leaving
such footers to be checked by maxLineLength() in the body rule.

Respect footer-max-line-length for footer lines (do not fail body-max-line-length)
@commitlint/rules/src/body-max-line-length.ts[5-36]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`body-max-line-length` is intended to ignore footer/trailer lines so they are not validated against the body max length. The current trailer detection regex (`TRAILER_TOKEN`) only matches hyphenated tokens (e.g., `Signed-off-by:`), which means other valid trailer/footer tokens (e.g., `Fixes:`, `Refs:`, `BREAKING CHANGE:`) may remain in the body input and still trigger `body-max-line-length` failures.

## Issue Context
Compliance requires that footer lines are not validated by `body-max-line-length` (they should be governed separately, e.g. by `footer-max-line-length`). The current implementation gates footer stripping on `TRAILER_TOKEN`, so missed trailer formats can violate that requirement.

## Fix Focus Areas
- @commitlint/rules/src/body-max-line-length.ts[5-37]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

2. Multi-trailer body not removed 🐞 Bug ≡ Correctness

Description

withoutTrailingFooter() removes a detected trailer paragraph via lines.slice(0, first), but when
the body contains only multiple trailer lines (no blank separator), first becomes -1 and the
function returns all but the last trailer line. This can still trigger bodyMaxLineLength failures
for long trailer lines in commits that contain only trailers (e.g., Signed-off-by +
Co-authored-by).

Code

@commitlint/rules/src/body-max-line-length.ts[R24-37]

+	let first = last;
+
+	while (first >= 0 && lines[first] !== "") {
+		first--;
+	}
+
+	const footerLines = lines.slice(first + 1, last + 1);
+
+	if (footerLines.length === 0 || !footerLines.every((line) => TRAILER_TOKEN.test(line))) {
+		return input;
+	}
+
+	return lines.slice(0, first).join("\n");
+}

Evidence

The code can set first to -1 when there is no blank line in input; in that case
lines.slice(0, first) becomes slice(0, -1) which keeps all elements except the last, leaving
trailer lines behind. toLines() splits the body into multiple lines, so a trailer-only body with
multiple trailer lines triggers this path.

@commitlint/rules/src/body-max-line-length.ts[17-37]
@commitlint/to-lines/src/index.ts[1-7]
@commitlint/rules/src/trailer-exists.ts[6-12]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`withoutTrailingFooter()` can detect that the entire body is made of trailer lines, but when there is no blank line separator, `first` ends up as `-1` and `lines.slice(0, first)` drops only the last trailer line (because `slice(0, -1)` keeps all-but-last). This leaves remaining trailer lines in the body, so `body-max-line-length` can still fail on long trailer lines.

## Issue Context
This happens when the commit has no body and contains multiple trailers (e.g., `Signed-off-by: ...` followed by `Co-authored-by: ...`) that are present in `parsed.body` (trailers are commonly handled via raw parsing / `git interpret-trailers`).

## Fix Focus Areas
- @commitlint/rules/src/body-max-line-length.ts[24-37]

### Suggested change
Special-case `first < 0` to remove the entire input (return empty string) when the last paragraph is detected as trailers.

### Add regression test
Add a test where the commit message has *no body* and *multiple* trailer lines, and ensure `bodyMaxLineLength` returns `true` when the trailers exceed the body limit (since they should be ignored).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

qodo-code-review · 2026-06-04T23:45:47Z

+const TRAILER_TOKEN = /^[A-Za-z0-9]+(?:-[A-Za-z0-9]+)+:\s\S/;
+
+function withoutTrailingFooter(body: string, footer?: string | null): string {
+	const footerStart = footer ? body.length - footer.length : -1;
+	const input =
+		footer &&
+		footerStart >= 0 &&
+		body.endsWith(footer) &&
+		(footerStart === 0 || body[footerStart - 1] === "\n")
+			? body.slice(0, footerStart).replace(/(\r?\n)+$/, "")
+			: body;
+
+	const lines = toLines(input);
+	let last = lines.length - 1;
+
+	while (last >= 0 && lines[last] === "") {
+		last--;
+	}
+
+	let first = last;
+
+	while (first >= 0 && lines[first] !== "") {
+		first--;
+	}
+
+	const footerLines = lines.slice(first + 1, last + 1);
+
+	if (footerLines.length === 0 || !footerLines.every((line) => TRAILER_TOKEN.test(line))) {
+		return input;


1. trailer_token excludes valid footers 📎 Requirement gap ≡ Correctness

withoutTrailingFooter() only treats the last paragraph as a footer if every line matches TRAILER_TOKEN, but the regex requires a hyphenated token and will miss valid trailers like Fixes:/Refs:/BREAKING CHANGE:. As a result, some footer lines can still be checked by body-max-line-length, violating the requirement that footer line-length is not enforced by the body rule.

Agent Prompt

## Issue description `body-max-line-length` is intended to ignore footer/trailer lines so they are not validated against the body max length. The current trailer detection regex (`TRAILER_TOKEN`) only matches hyphenated tokens (e.g., `Signed-off-by:`), which means other valid trailer/footer tokens (e.g., `Fixes:`, `Refs:`, `BREAKING CHANGE:`) may remain in the body input and still trigger `body-max-line-length` failures. ## Issue Context Compliance requires that footer lines are not validated by `body-max-line-length` (they should be governed separately, e.g. by `footer-max-line-length`). The current implementation gates footer stripping on `TRAILER_TOKEN`, so missed trailer formats can violate that requirement. ## Fix Focus Areas - @commitlint/rules/src/body-max-line-length.ts[5-37]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

qodo-code-review · 2026-06-04T23:45:47Z

+	let first = last;
+
+	while (first >= 0 && lines[first] !== "") {
+		first--;
+	}
+
+	const footerLines = lines.slice(first + 1, last + 1);
+
+	if (footerLines.length === 0 || !footerLines.every((line) => TRAILER_TOKEN.test(line))) {
+		return input;
+	}
+
+	return lines.slice(0, first).join("\n");
+}


2. Multi-trailer body not removed 🐞 Bug ≡ Correctness

withoutTrailingFooter() removes a detected trailer paragraph via lines.slice(0, first), but when the body contains only multiple trailer lines (no blank separator), first becomes -1 and the function returns all but the last trailer line. This can still trigger bodyMaxLineLength failures for long trailer lines in commits that contain only trailers (e.g., Signed-off-by + Co-authored-by).

Agent Prompt

## Issue description `withoutTrailingFooter()` can detect that the entire body is made of trailer lines, but when there is no blank line separator, `first` ends up as `-1` and `lines.slice(0, first)` drops only the last trailer line (because `slice(0, -1)` keeps all-but-last). This leaves remaining trailer lines in the body, so `body-max-line-length` can still fail on long trailer lines. ## Issue Context This happens when the commit has no body and contains multiple trailers (e.g., `Signed-off-by: ...` followed by `Co-authored-by: ...`) that are present in `parsed.body` (trailers are commonly handled via raw parsing / `git interpret-trailers`). ## Fix Focus Areas - @commitlint/rules/src/body-max-line-length.ts[24-37] ### Suggested change Special-case `first < 0` to remove the entire input (return empty string) when the last paragraph is detected as trailers. ### Add regression test Add a test where the commit message has *no body* and *multiple* trailer lines, and ensure `bodyMaxLineLength` returns `true` when the trailers exceed the body limit (since they should be ignored).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

escapedcat · 2026-06-05T08:35:08Z

@puneetdixit200 thanks for the PR! Could you please:

Split up the commit into two commits
- one adding the test only, push it, CI will fail
- a second one that pushes the fix, CI will be green
  This will be a more transparent TDD approach
Have a look at the feedback from qodo and copilot, either tackle it or comment why it's not valid

Thanks!

Copilot

Pull request overview

This PR updates the body-max-line-length rule to ignore trailing footer/trailer paragraphs when evaluating body line lengths, fixing cases where long trailer lines (e.g. Signed-off-by) incorrectly fail the body rule instead of being handled by footer/trailer-related rules.

Changes:

Add logic to strip a trailing “trailer paragraph” (and optionally an already-parsed footer) from parsed.body before applying maxLineLength.
Add a regression test ensuring a long Signed-off-by: trailer line doesn’t cause body-max-line-length to fail.

Reviewed changes

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

File	Description
@commitlint/rules/src/body-max-line-length.ts	Introduces footer/trailer-stripping logic prior to applying the body line-length check.
@commitlint/rules/src/body-max-line-length.test.ts	Adds a regression test for long trailer lines to ensure body line-length validation ignores them.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

+		return input;
+	}
+
+	return lines.slice(0, first).join("\n");


+	const expected = true;
+	expect(actual).toEqual(expected);
+});
+


fix(rules): ignore footer lines in body max length

bf74d45

qodo-code-review Bot reviewed Jun 4, 2026

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mishlerronald292-maker approved these changes Jun 5, 2026

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escapedcat requested a review from Copilot June 5, 2026 08:31

Copilot started reviewing on behalf of escapedcat June 5, 2026 08:31 View session

Copilot AI reviewed Jun 5, 2026

View reviewed changes

Comment thread @commitlint/rules/src/body-max-line-length.ts

return input;

}

return lines.slice(0, first).join("\n");

Comment thread @commitlint/rules/src/body-max-line-length.test.ts

const expected = true;

expect(actual).toEqual(expected);

});

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fix(rules): ignore footer lines in body max length#4813

fix(rules): ignore footer lines in body max length#4813
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puneetdixit200 commented Jun 4, 2026

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qodo-code-review Bot commented Jun 4, 2026

Review Summary by Qodo

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qodo-code-review Bot commented Jun 4, 2026 •

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