rules: accept revert commit titles that were elongated by git

This change ensures that the commit message linter doesn't reject
revert commits that originally had commit titles with an acceptable
length but were elongated during the revert process by running
`git revert`.

Fixes: nodejs#97
Signed-off-by: Darshan Sen <raisinten@gmail.com>

lib/rules/title-length.js

@@ -17,7 +17,8 @@ module.exports = {
     max_length: 72
   },
   validate: (context, rule) => {
-    const max = rule.options.max_length
+    const is_revert_commit = /^Revert ".*"$/.test(context.title)
+    const max = rule.options.max_length + (is_revert_commit ? 'Revert ""'.length : 0)
     if (context.title.length > max) {
       context.report({
         id: id,
@@ -31,7 +32,7 @@ module.exports = {
       return
     }
 
-    const len = rule.options.length
+    const len = rule.options.length + (is_revert_commit ? 'Revert ""'.length : 0)
     if (context.title.length > len) {
       context.report({
         id: id,

test/validator.js

@@ -25,7 +25,7 @@ const str2 = `commit b6475b9a9d0da0971eec7eb5559dff4d18a0e721
 Author: Evan Lucas <evanlucas@me.com>
 Date:   Tue Mar 29 08:09:37 2016 -0500
 
-    Revert "tty: don't read from console stream upon creation"
+    Revert "tty: do not read from the console stream upon creation"
 
     This reverts commit 461138929498f31bd35bea61aa4375a2f56cceb7.
 
@@ -127,6 +127,42 @@ Date:   Thu Mar 3 10:10:46 2016 -0600
     test: Check memoryUsage properties.
 `
 
+const str10 = `commit b04fe688d5859f707cf1a5e0206967268118bf7a
+Author: Darshan Sen <raisinten@gmail.com>
+Date:   Sun May 1 21:10:21 2022 +0530
+
+    Revert "bootstrap: delay the instantiation of maps in per-context scripts"
+
+    The linked issue, https://bugs.chromium.org/p/v8/issues/detail?id=6593,
+    is marked as "Fixed", so I think we can revert this now.
+
+    This reverts commit 08a9c4a996964aca909cd75fa8ecafd652c54885.
+
+    Signed-off-by: Darshan Sen <raisinten@gmail.com>
+    PR-URL: https://github.com/nodejs/node/pull/42934
+    Refs: https://bugs.chromium.org/p/v8/issues/detail?id=9187
+    Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
+    Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
+`
+
+const str11 = `commit b04fe688d5859f707cf1a5e0206967268118bf7a
+Author: Darshan Sen <raisinten@gmail.com>
+Date:   Sun May 1 21:10:21 2022 +0530
+
+    Revert "bootstrap: delay the instantiation of all maps in the per-context scripts"
+
+    The linked issue, https://bugs.chromium.org/p/v8/issues/detail?id=6593,
+    is marked as "Fixed", so I think we can revert this now.
+
+    This reverts commit 08a9c4a996964aca909cd75fa8ecafd652c54885.
+
+    Signed-off-by: Darshan Sen <raisinten@gmail.com>
+    PR-URL: https://github.com/nodejs/node/pull/42934
+    Refs: https://bugs.chromium.org/p/v8/issues/detail?id=9187
+    Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
+    Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
+`
+
 test('Validator - misc', (t) => {
   const v = new Validator()
 
@@ -215,6 +251,49 @@ test('Validator - real commits', (t) => {
     })
   })
 
+  t.test('accept revert commit titles that are elongated by git', (tt) => {
+    const v = new Validator()
+    v.lint(str10)
+    v.on('commit', (data) => {
+      const c = data.commit.toJSON()
+      tt.equal(c.sha, 'b04fe688d5859f707cf1a5e0206967268118bf7a', 'sha')
+      tt.equal(c.date, 'Sun May 1 21:10:21 2022 +0530', 'date')
+      tt.deepEqual(c.subsystems, ['bootstrap'], 'subsystems')
+      tt.equal(c.prUrl, 'https://github.com/nodejs/node/pull/42934', 'pr')
+      tt.equal(c.revert, true, 'revert')
+      const msgs = data.messages
+      const filtered = msgs.filter((item) => {
+        return item.level === 'fail'
+      })
+      tt.equal(filtered.length, 0, 'messages.length')
+      tt.end()
+    })
+  })
+
+  t.test('reject revert commit titles whose original titles are really long', (tt) => {
+    const v = new Validator()
+    v.lint(str11)
+    v.on('commit', (data) => {
+      const c = data.commit.toJSON()
+      tt.equal(c.sha, 'b04fe688d5859f707cf1a5e0206967268118bf7a', 'sha')
+      tt.equal(c.date, 'Sun May 1 21:10:21 2022 +0530', 'date')
+      tt.deepEqual(c.subsystems, ['bootstrap'], 'subsystems')
+      tt.equal(c.prUrl, 'https://github.com/nodejs/node/pull/42934', 'pr')
+      tt.equal(c.revert, true, 'revert')
+      const msgs = data.messages
+      const filtered = msgs.filter((item) => {
+        return item.level === 'fail'
+      })
+      tt.equal(filtered.length, 1, 'messages.length')
+      const ids = filtered.map((item) => {
+        return item.id
+      })
+      const exp = ['title-length']
+      tt.deepEqual(ids.sort(), exp.sort(), 'message ids')
+      tt.end()
+    })
+  })
+
   t.test('invalid pr-url, missing subsystem', (tt) => {
     const v = new Validator()
     v.lint(str4)