fix(platform/gitlab): Strip unicode null characters from markdown (#1…

…9664)

Co-authored-by: Michael Kriese <michael.kriese@visualon.de>
Co-authored-by: Rhys Arkins <rhys@arkins.net>

lib/modules/platform/gitlab/index.spec.ts

@@ -2046,6 +2046,12 @@ These updates have all been created already. Click a checkbox below to force a r
 `;
 
   describe('massageMarkdown(input)', () => {
+    it('strips invalid unicode null characters', () => {
+      expect(
+        gitlab.massageMarkdown("The source contains 'Ruby\u0000' at: 2.7.6.219")
+      ).toBe("The source contains 'Ruby' at: 2.7.6.219");
+    });
+
     it('returns updated pr body', async () => {
       jest.mock('../utils/pr-body');
       const { smartTruncate } = require('../utils/pr-body');

lib/modules/platform/gitlab/index.ts

@@ -697,7 +697,9 @@ export function massageMarkdown(input: string): string {
   let desc = input
     .replace(regEx(/Pull Request/g), 'Merge Request')
     .replace(regEx(/PR/g), 'MR')
-    .replace(regEx(/\]\(\.\.\/pull\//g), '](!');
+    .replace(regEx(/\]\(\.\.\/pull\//g), '](!')
+    // Strip unicode null characters as GitLab markdown does not permit them
+    .replace(regEx(/\u0000/g), ''); // eslint-disable-line no-control-regex
 
   if (semver.lt(defaults.version, '13.4.0')) {
     logger.debug(