fix(cli): use core.commentChar from git config with --edit flag (conventional-changelog#3190)

When parsing `.git/COMMIT_EDITMSG` use the `core.commentChar` git
setting if present, falling back to the default comment char `#`
otherwise.

Use the `parserOpts.commentChar` setting only when parsing other
messages (e.g. from stdin.)

Author: jscheid

@commitlint/cli/fixtures/comment-char/commitlint.config.js

@@ -1,6 +1,6 @@
 module.exports = {
 	rules: {
-		'subject-empty': [2, 'never']
+		'body-empty': [2, 'never']
 	},
 	parserPreset: {
         parserOpts: {

@commitlint/cli/package.json

@@ -41,7 +41,6 @@
     "@commitlint/utils": "^17.0.0",
     "@types/node": "12.20.52",
     "@types/yargs": "^17.0.0",
-    "execa": "^5.0.0",
     "fs-extra": "^10.0.0"
   },
   "dependencies": {
@@ -50,6 +49,7 @@
     "@commitlint/load": "^17.0.0",
     "@commitlint/read": "^17.0.0",
     "@commitlint/types": "^17.0.0",
+    "execa": "^5.0.0",
     "lodash": "^4.17.19",
     "resolve-from": "5.0.0",
     "resolve-global": "1.0.0",

@commitlint/cli/src/cli.test.ts

@@ -329,13 +329,50 @@ test('should handle --amend with signoff', async () => {
 	expect(commit).toBeTruthy();
 }, 10000);
 
-test('should fail with an empty message and a commentChar is set', async () => {
+test('it uses parserOpts.commentChar when not using edit mode', async () => {
 	const cwd = await gitBootstrap('fixtures/comment-char');
-	await execa('git', ['config', '--local', 'core.commentChar', '$'], {cwd});
-	await fs.writeFile(path.join(cwd, '.git', 'COMMIT_EDITMSG'), '#1234');
+	const input = 'header: foo\n$body\n';
+
+	const actual = await cli([], {cwd})(input);
+	expect(actual.stdout).toContain('[body-empty]');
+	expect(actual.exitCode).toBe(1);
+});
+
+test("it doesn't use parserOpts.commentChar when using edit mode", async () => {
+	const cwd = await gitBootstrap('fixtures/comment-char');
+	await fs.writeFile(
+		path.join(cwd, '.git', 'COMMIT_EDITMSG'),
+		'header: foo\n\n$body\n'
+	);
+
+	const actual = await cli(['--edit', '.git/COMMIT_EDITMSG'], {cwd})();
+	expect(actual.stdout).not.toContain('[body-empty]');
+	expect(actual.exitCode).toBe(0);
+});
+
+test('it uses core.commentChar git config when using edit mode', async () => {
+	const cwd = await gitBootstrap('fixtures/comment-char');
+	await execa('git', ['config', 'core.commentChar', '$'], {cwd});
+	await fs.writeFile(
+		path.join(cwd, '.git', 'COMMIT_EDITMSG'),
+		'header: foo\n\n$body\n'
+	);
+
+	const actual = await cli(['--edit', '.git/COMMIT_EDITMSG'], {cwd})();
+	expect(actual.stdout).toContain('[body-empty]');
+	expect(actual.exitCode).toBe(1);
+});
+
+test('it falls back to # for core.commentChar when using edit mode', async () => {
+	const cwd = await gitBootstrap('fixtures/comment-char');
+	await execa('git', ['config', 'core.commentChar', ''], {cwd});
+	await fs.writeFile(
+		path.join(cwd, '.git', 'COMMIT_EDITMSG'),
+		'header: foo\n\n#body\n'
+	);
 
 	const actual = await cli(['--edit', '.git/COMMIT_EDITMSG'], {cwd})();
-	expect(actual.stdout).toContain('[subject-empty]');
+	expect(actual.stdout).toContain('[body-empty]');
 	expect(actual.exitCode).toBe(1);
 });
 

@commitlint/cli/src/cli.ts

@@ -1,3 +1,4 @@
+import execa from 'execa';
 import load from '@commitlint/load';
 import lint from '@commitlint/lint';
 import read from '@commitlint/read';
@@ -21,6 +22,8 @@ import {CliError} from './cli-error';
 
 const pkg = require('../package');
 
+const gitDefaultCommentChar = '#';
+
 const cli = yargs
 	.options({
 		color: {
@@ -221,11 +224,16 @@ async function main(args: MainArgs) {
 	}
 	const format = loadFormatter(loaded, flags);
 
-	// Strip comments if reading from `.git/COMMIT_EDIT_MSG` using the
-	// commentChar from the parser preset falling back to a `#` if that is not
-	// set
-	if (flags.edit && typeof opts.parserOpts.commentChar !== 'string') {
-		opts.parserOpts.commentChar = '#';
+	// If reading from `.git/COMMIT_EDIT_MSG`, strip comments using
+	// core.commentChar from git configuration, falling back to '#'.
+	if (flags.edit) {
+		try {
+			const {stdout} = await execa('git', ['config', 'core.commentChar']);
+			opts.parserOpts.commentChar = stdout.trim() || gitDefaultCommentChar;
+		} catch (e) {
+			console.warn('Could not determine core.commentChar git configuration', e);
+			opts.parserOpts.commentChar = gitDefaultCommentChar;
+		}
 	}
 
 	const results = await Promise.all(

@packages/test/src/git.ts

@@ -35,6 +35,7 @@ async function setup(cwd: string, gitCommand = 'git') {
 			cwd,
 		});
 		await execa(gitCommand, ['config', 'commit.gpgsign', 'false'], {cwd});
+		await execa(gitCommand, ['config', 'core.commentChar', '#'], {cwd});
 	} catch (err: any) {
 		if (typeof err === 'object' && typeof err.message === 'object') {
 			console.warn(`git config in ${cwd} failed`, err.message);