nodejs · aduh95 · Apr 15, 2026
diff --git a/lib/gitlint-parser.js b/lib/gitlint-parser.js
@@ -0,0 +1,171 @@
+import { spawnSync } from 'node:child_process'
+import Base from 'gitlint-parser-base'
+
+const revertRE = /Revert "(.*)"$/
+const workingRE = /Working on v([\d]+)\.([\d]+).([\d]+)$/
+const releaseRE = /([\d]{4})-([\d]{2})-([\d]{2}),? Version/
+const reviewedByRE = /^Reviewed-By: (.*)$/
+const fixesRE = /^Fixes: (.*)$/
+const prUrlRE = /^PR-URL: (.*)$/
+const refsRE = /^Refs?: (.*)$/
+
+export default class Parser extends Base {
+  constructor (str, validator) {
+    super(str, validator)
+    this.subsystems = []
+    this.fixes = []
+    this.prUrl = null
+    this.refs = []
+    this.reviewers = []
+    this._metaStart = 0
+    this._metaEnd = 0
+    this._parse()
+  }
+
+  _setMetaStart (n) {
+    if (this._metaStart) return
+    this._metaStart = n
+  }
+
+  _setMetaEnd (n) {
+    if (n < this._metaEnd) return
+    this._metaEnd = n
+  }
+
+  _parseTrailers (body) {
+    const interpretTrailers = commitMessage => spawnSync('git', [
+      'interpret-trailers', '--only-trailers', '--only-input', '--no-divider'
+    ], {
+      encoding: 'utf-8',
+      input: `${commitMessage}\n`
+    }).stdout
+
+    let originalTrailers
+    try {
+      originalTrailers = interpretTrailers(body.join('\n')).trim()
+    } catch (err) {
+      console.warn('git is not available, trailers detection might be a bit ' +
+                   'off which is acceptable in most cases', err)
+      return body
+    }
+    const trailerFreeBody = body.slice(1) // clone, and remove the first empty line
+    const stillInTrailers = () => {
+      const result = interpretTrailers(trailerFreeBody.join('\n'))
+      return result.length && originalTrailers.startsWith(result.trim())
+    }
+    for (let i = trailerFreeBody.length - 1; stillInTrailers(); i--) {
+      // Remove last line until git no longer detects any trailers
+      trailerFreeBody.pop()
+    }
+    this._metaStart = trailerFreeBody.length + 1
+    for (let i = trailerFreeBody.length - 1; trailerFreeBody[i] === ''; i--) {
+      // Remove additional empty line(s)
+      trailerFreeBody.pop()
+    }
+    this._metaEnd = body.length - 1
+    this.trailerFreeBody = trailerFreeBody
+    return (this.trailers = originalTrailers.split('\n'))
+  }
+
+  _parse () {
+    const revert = this.isRevert()
+    if (!revert) {
+      this.subsystems = getSubsystems(this.title || '')
+    } else {
+      const matches = this.title.match(revertRE)
+      if (matches) {
+        const title = matches[1]
+        this.subsystems = getSubsystems(title)
+      }
+    }
+
+    const trailers = this._parseTrailers(this.body)
+
+    for (let i = 0; i < trailers.length; i++) {
+      const line = trailers[i]
+      const reviewedBy = reviewedByRE.exec(line)
+      if (reviewedBy) {
+        this._setMetaStart(i)
+        this._setMetaEnd(i)
+        this.reviewers.push(reviewedBy[1])
+        continue
+      }
+
+      const fixes = fixesRE.exec(line)
+      if (fixes) {
+        this._setMetaStart(i)
+        this._setMetaEnd(i)
+        this.fixes.push(fixes[1])
+        continue
+      }
+
+      const prUrl = prUrlRE.exec(line)
+      if (prUrl) {
+        this._setMetaStart(i)
+        this._setMetaEnd(i)
+        this.prUrl = prUrl[1]
+        continue
+      }
+
+      const refs = refsRE.exec(line)
+      if (refs) {
+        this._setMetaStart(i)
+        this._setMetaEnd(i)
+        this.refs.push(refs[1])
+        continue
+      }
+
+      if (this._metaStart && !this._metaEnd) { this._setMetaEnd(i) }
+    }
+  }
+
+  isRevert () {
+    return revertRE.test(this.title)
+  }
+
+  isWorkingCommit () {
+    return workingRE.test(this.title)
+  }
+
+  isReleaseCommit () {
+    return releaseRE.test(this.title)
+  }
+
+  toJSON () {
+    return {
+      sha: this.sha,
+      title: this.title,
+      subsystems: this.subsystems,
+      author: this.author,
+      date: this.date,
+      fixes: this.fixes,
+      refs: this.refs,
+      prUrl: this.prUrl,
+      reviewers: this.reviewers,
+      body: this.body,
+      trailers: this.trailers,
+      trailerFreeBody: this.trailerFreeBody,
+      revert: this.isRevert(),
+      release: this.isReleaseCommit(),
+      working: this.isWorkingCommit(),
+      metadata: {
+        start: this._metaStart,
+        end: this._metaEnd
+      }
+    }
+  }
+}
+
+function getSubsystems (str) {
+  str = str || ''
+  const colon = str.indexOf(':')
+  if (colon === -1) {
+    return []
+  }
+
+  const subStr = str.slice(0, colon)
+  const subs = subStr.split(',')
+  return subs.map((item) => {
+    return item.trim()
+  })
+}
diff --git a/lib/rules/line-length.js b/lib/rules/line-length.js
@@ -7,10 +7,12 @@ export default {
     recommended: true
   },
   defaults: {
-    length: 72
+    length: 72,
+    trailerLength: 120
   },
   options: {
-    length: 72
+    length: 72,
+    trailerLength: 120
   },
   validate: (context, rule) => {
     const len = rule.options.length
@@ -27,19 +29,14 @@ export default {
       return
     }
     let failed = false
-    for (let i = 0; i < parsed.body.length; i++) {
-      const line = parsed.body[i]
+    const body = parsed.trailerFreeBody ?? parsed.body
+    for (let i = 0; i < body.length; i++) {
+      const line = body[i]
 
       // Skip quoted lines, e.g. for original commit messages of V8 backports.
       if (line.startsWith('    ')) { continue }
       // Skip lines with URLs.
       if (/https?:\/\//.test(line)) { continue }
-      // Skip co-authorship.
-      if (/^co-authored-by:/i.test(line)) { continue }
-      // Skip DCO sign-offs.
-      if (/^signed-off-by:/i.test(line)) { continue }
-      // Skip agentic assistants.
-      if (/^assisted-by:/i.test(line)) { continue }
 
       if (line.length > len) {
         failed = true
@@ -54,6 +51,22 @@ export default {
         })
       }
     }
+    for (let i = 0; i < (parsed.trailers?.length ?? 0); i++) {
+      const line = parsed.trailers[i]
+      const len = rule.options.trailerLength
+      if (line.length > len) {
+        failed = true
+        context.report({
+          id,
+          message: `Trailer should be <= ${len} columns.`,
+          string: line,
+          maxLength: len,
+          line: i + parsed.body.length - parsed.trailers.length,
+          column: len,
+          level: 'fail'
+        })
+      }
+    }
 
     if (!failed) {
       context.report({

diff --git a/lib/rules/signed-off-by.js b/lib/rules/signed-off-by.js
@@ -67,10 +67,12 @@ export default {
       return
     }
 
+    const body = parsed.trailers ?? parsed.body
+
     // Backport commits (identified by a Backport-PR-URL trailer) are
     // cherry-picks of existing commits into release branches. The
     // original commit was already validated.
-    if (parsed.body.some((line) => backportPattern.test(line))) {
+    if (body.some((line) => backportPattern.test(line))) {
       context.report({
         id,
         message: 'skipping sign-off for backport commit',
@@ -80,9 +82,9 @@ export default {
       return
     }
 
-    const signoffs = parsed.body
-      .map((line, i) => [line, i])
-      .filter(([line]) => signoffPattern.test(line))
+    const signoffs = body
+      .filter(line => signoffPattern.test(line))
+      .map((line, i) => [line, i + parsed.body.length - body.length])
 
     // Bot-authored commits don't need a sign-off.
     // If they have one, warn; otherwise pass.

diff --git a/lib/validator.js b/lib/validator.js
@@ -1,5 +1,5 @@
 import EE from 'node:events'
-import Parser from 'gitlint-parser-node'
+import Parser from './gitlint-parser.js'
 import BaseRule from './rule.js'
 
 // Rules