Accept changelog headings with or without a colon (#59219)

Summary:
Allow Analyze Pull Request to recognize both `## Changelog` and `## Changelog:` in PR descriptions. The PR template uses a colon, but a properly tagged changelog under a heading without one was incorrectly reported as missing. Preserve the existing colon format and requirement for a tagged entry. Remove the stateful global flag from the internal changelog pattern so repeated validations agree.

## Changelog:

[INTERNAL] [FIXED] - Accept changelog headings with or without a colon in PR validation.

Pull Request resolved: #59219

Test Plan:
- `yarn test .github/workflow-scripts/__tests__/validatePRBody-test.js --runInBand --silent` — passed (6 tests).
- `yarn prettier .github/workflow-scripts/validatePRBody.js .github/workflow-scripts/__tests__/validatePRBody-test.js --check` — passed.
- `yarn lint` — passed.
- `git diff --check` — passed.

No UI changes; screenshots are not applicable.

Reviewed By: cipolleschi

Differential Revision: D126318404

Pulled By: cortinico

fbshipit-source-id: aac410fba37299a3c2de5d238e21527968acd7fd

Author: cortinico

.github/workflow-scripts/__tests__/validatePRBody-test.js

@@ -0,0 +1,62 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+'use strict';
+
+const validatePRBody = require('../validatePRBody');
+
+function prBody(changelog) {
+  return `## Summary
+
+Explain why the change is needed.
+
+${changelog}
+
+## Test Plan
+
+Run the unit tests.`;
+}
+
+describe('validatePRBody changelog headings', () => {
+  it.each(['## Changelog', '## Changelog:'])(
+    'accepts %s with a tagged entry',
+    heading => {
+      expect(
+        validatePRBody(prBody(`${heading}\n\n[GENERAL] [FIXED] - Fix a bug`)),
+      ).toEqual({message: '', status: 'PASS'});
+    },
+  );
+
+  it('accepts a heading without a colon with CRLF line endings', () => {
+    const body = prBody('## Changelog\n\n[INTERNAL] [FIXED] - Fix CI');
+    expect(validatePRBody(body.replace(/\n/g, '\r\n'))).toEqual({
+      message: '',
+      status: 'PASS',
+    });
+  });
+
+  it('accepts consecutive internal changelogs consistently', () => {
+    const body = prBody('## Changelog\n\n[INTERNAL] [FIXED] - Fix CI');
+    expect(validatePRBody(body).status).toBe('PASS');
+    expect(validatePRBody(body).status).toBe('PASS');
+  });
+
+  it('still requires a tagged entry', () => {
+    expect(validatePRBody(prBody('## Changelog\n\nNo tags')).message).toContain(
+      'Invalid Changelog Format',
+    );
+  });
+
+  it('does not treat an unmarked Changelog line as a heading', () => {
+    expect(
+      validatePRBody(prBody('Changelog\n\n[GENERAL] [FIXED] - Fix a bug'))
+        .message,
+    ).toContain('Missing Changelog');
+  });
+});

.github/workflow-scripts/validatePRBody.js

@@ -12,14 +12,15 @@
 const changelogRegex =
   /\[\s?(ANDROID|GENERAL|IOS|INTERNAL)\s?\]\s?\[\s?(BREAKING|ADDED|CHANGED|DEPRECATED|REMOVED|FIXED|SECURITY)\s?\]\s*?-?\s*?(.*)/i;
 
-const internalChangelogRegex = /\[\s?(INTERNAL)\s?\].*/gi;
+const internalChangelogRegex = /\[\s?(INTERNAL)\s?\].*/i;
 
-function validateChangelog(commitMsg) {
-  if (!commitMsg.toLowerCase().includes('changelog:')) {
+function validateChangelog(prBody) {
+  const hasChangelogHeading = /^##[ \t]+changelog[ \t]*\r?$/im.test(prBody);
+  if (!prBody.toLowerCase().includes('changelog:') && !hasChangelogHeading) {
     return 'missing';
   }
-  const hasValidChangelog = changelogRegex.test(commitMsg);
-  const hasValidInternalChangelog = internalChangelogRegex.test(commitMsg);
+  const hasValidChangelog = changelogRegex.test(prBody);
+  const hasValidInternalChangelog = internalChangelogRegex.test(prBody);
 
   if (hasValidChangelog || hasValidInternalChangelog) {
     return 'valid';