fix(github): Massage links to issues, pulls or discussions

.eslintrc.js

@@ -51,6 +51,9 @@ module.exports = {
         memberSyntaxSortOrder: ['none', 'all', 'multiple', 'single'],
       },
     ],
+
+    // mdast is a types only package `@types/mdast`
+    'import/no-unresolved': ['error', { ignore: ['^mdast$'] }],
     'import/order': [
       'error',
       {

lib/platform/github/__snapshots__/index.spec.ts.snap

@@ -7772,7 +7772,7 @@ Array [
 ]
 `;
 
-exports[`platform/github/index massageMarkdown(input) returns updated pr body 1`] = `"https://github.com/foo/bar/issues/5 plus also [a link](https://togithub.com/foo/bar/issues/5)"`;
+exports[`platform/github/index massageMarkdown(input) returns updated pr body 1`] = `"[https://github.com/foo/bar/issues/5](https://togithub.com/foo/bar/issues/5) plus also [a link](https://togithub.com/foo/bar/issues/5)"`;
 
 exports[`platform/github/index mergePr(prNo) - autodetection should give up 1`] = `
 Array [

lib/platform/github/index.ts

@@ -49,6 +49,7 @@ import {
   repoInfoQuery,
   vulnerabilityAlertsQuery,
 } from './graphql';
+import { massageMarkdownLinks } from './massage-markdown-links';
 import {
   BranchProtection,
   CombinedBranchStatus,
@@ -1569,7 +1570,7 @@ export function massageMarkdown(input: string): string {
   if (config.isGhe) {
     return smartTruncate(input, 60000);
   }
-  const massagedInput = input
+  const massagedInput = massageMarkdownLinks(input)
     // to be safe, replace all github.com links with renovatebot redirector
     .replace(/href="https?:\/\/github.com\//g, 'href="https://togithub.com/')
     .replace(/]\(https:\/\/github\.com\//g, '](https://togithub.com/')

lib/platform/github/massage-markdown-links.spec.ts

@@ -0,0 +1,90 @@
+import { getName } from '../../../test/util';
+import { massageMarkdownLinks } from './massage-markdown-links';
+
+describe(getName(), () => {
+  it('performs multiple replacements', () => {
+    const input = [
+      'Link [foo/bar#1](https://github.com/foo/bar/pull/1) points to https://github.com/foo/bar/pull/1.',
+      'URL https://github.com/foo/bar/pull/1 becomes [foo/bar#1](https://github.com/foo/bar/pull/1).',
+    ].join('\n');
+    const res = massageMarkdownLinks(input);
+    expect(res).toEqual(
+      [
+        'Link [foo/bar#1](https://togithub.com/foo/bar/pull/1) points to [https://github.com/foo/bar/pull/1](https://togithub.com/foo/bar/pull/1).',
+        'URL [https://github.com/foo/bar/pull/1](https://togithub.com/foo/bar/pull/1) becomes [foo/bar#1](https://togithub.com/foo/bar/pull/1).',
+      ].join('\n')
+    );
+  });
+
+  test.each`
+    input
+    ${'github.com'}
+    ${'github.com/foo/bar'}
+    ${'github.com/foo/bar/'}
+    ${'github.com/foo/bar/discussions'}
+    ${'github.com/foo/bar/issues'}
+    ${'github.com/foo/bar/pull'}
+    ${'github.com/foo/bar/discussions/'}
+    ${'github.com/foo/bar/issues/'}
+    ${'github.com/foo/bar/pull/'}
+    ${'www.github.com'}
+    ${'www.github.com/foo/bar'}
+    ${'www.github.com/foo/bar/'}
+    ${'www.github.com/foo/bar/discussions'}
+    ${'www.github.com/foo/bar/issues'}
+    ${'www.github.com/foo/bar/pull'}
+    ${'www.github.com/foo/bar/discussions/'}
+    ${'www.github.com/foo/bar/issues/'}
+    ${'www.github.com/foo/bar/pull/'}
+    ${'https://github.com'}
+    ${'https://github.com/foo/bar'}
+    ${'https://github.com/foo/bar/'}
+    ${'https://github.com/foo/bar/discussions'}
+    ${'https://github.com/foo/bar/issues'}
+    ${'https://github.com/foo/bar/pull'}
+    ${'https://github.com/foo/bar/discussions/'}
+    ${'https://github.com/foo/bar/issues/'}
+    ${'https://github.com/foo/bar/pull/'}
+    ${'api.github.com'}
+    ${'togithub.com'}
+    ${'www.togithub.com'}
+    ${'https://togithub.com/foo/bar/releases/tag/v0.20.3'}
+    ${'https://togithub.com/foo/bar/compare/v0.20.2...v0.20.3'}
+  `('Unchanged: $input', ({ input }: { input: string }) => {
+    const inputText = `Foo ${input}, bar.`;
+    expect(massageMarkdownLinks(inputText)).toEqual(inputText);
+
+    const inputLink = `[foobar](${input})`;
+    expect(massageMarkdownLinks(inputLink)).toEqual(inputLink);
+  });
+
+  test.each`
+    input                                                                                     | output
+    ${'github.com/foo/bar/discussions/1'}                                                     | ${'[github.com/foo/bar/discussions/1](togithub.com/foo/bar/discussions/1)'}
+    ${'github.com/foo/bar/issues/1'}                                                          | ${'[github.com/foo/bar/issues/1](togithub.com/foo/bar/issues/1)'}
+    ${'github.com/foo/bar/pull/1'}                                                            | ${'[github.com/foo/bar/pull/1](togithub.com/foo/bar/pull/1)'}
+    ${'www.github.com/foo/bar/discussions/1'}                                                 | ${'[www.github.com/foo/bar/discussions/1](www.togithub.com/foo/bar/discussions/1)'}
+    ${'www.github.com/foo/bar/issues/1'}                                                      | ${'[www.github.com/foo/bar/issues/1](www.togithub.com/foo/bar/issues/1)'}
+    ${'www.github.com/foo/bar/pull/1'}                                                        | ${'[www.github.com/foo/bar/pull/1](www.togithub.com/foo/bar/pull/1)'}
+    ${'https://github.com/foo/bar/discussions/1'}                                             | ${'[https://github.com/foo/bar/discussions/1](https://togithub.com/foo/bar/discussions/1)'}
+    ${'https://github.com/foo/bar/issues/1'}                                                  | ${'[https://github.com/foo/bar/issues/1](https://togithub.com/foo/bar/issues/1)'}
+    ${'https://github.com/foo/bar/pull/1'}                                                    | ${'[https://github.com/foo/bar/pull/1](https://togithub.com/foo/bar/pull/1)'}
+    ${'https://github.com/foo/bar/discussions/1#comment-123'}                                 | ${'[https://github.com/foo/bar/discussions/1#comment-123](https://togithub.com/foo/bar/discussions/1#comment-123)'}
+    ${'https://github.com/foo/bar/issues/1#comment-123'}                                      | ${'[https://github.com/foo/bar/issues/1#comment-123](https://togithub.com/foo/bar/issues/1#comment-123)'}
+    ${'https://github.com/foo/bar/pull/1#comment-123'}                                        | ${'[https://github.com/foo/bar/pull/1#comment-123](https://togithub.com/foo/bar/pull/1#comment-123)'}
+    ${'[github.com/foo/bar/discussions/1](github.com/foo/bar/discussions/1)'}                 | ${'[github.com/foo/bar/discussions/1](togithub.com/foo/bar/discussions/1)'}
+    ${'[github.com/foo/bar/issues/1](github.com/foo/bar/issues/1)'}                           | ${'[github.com/foo/bar/issues/1](togithub.com/foo/bar/issues/1)'}
+    ${'[github.com/foo/bar/pull/1](github.com/foo/bar/pull/1)'}                               | ${'[github.com/foo/bar/pull/1](togithub.com/foo/bar/pull/1)'}
+    ${'[www.github.com/foo/bar/discussions/1](www.github.com/foo/bar/discussions/1)'}         | ${'[www.github.com/foo/bar/discussions/1](www.togithub.com/foo/bar/discussions/1)'}
+    ${'[www.github.com/foo/bar/issues/1](www.github.com/foo/bar/issues/1)'}                   | ${'[www.github.com/foo/bar/issues/1](www.togithub.com/foo/bar/issues/1)'}
+    ${'[www.github.com/foo/bar/pull/1](www.github.com/foo/bar/pull/1)'}                       | ${'[www.github.com/foo/bar/pull/1](www.togithub.com/foo/bar/pull/1)'}
+    ${'[https://github.com/foo/bar/discussions/1](https://github.com/foo/bar/discussions/1)'} | ${'[https://github.com/foo/bar/discussions/1](https://togithub.com/foo/bar/discussions/1)'}
+    ${'[https://github.com/foo/bar/issues/1](https://github.com/foo/bar/issues/1)'}           | ${'[https://github.com/foo/bar/issues/1](https://togithub.com/foo/bar/issues/1)'}
+    ${'[https://github.com/foo/bar/pull/1](https://github.com/foo/bar/pull/1)'}               | ${'[https://github.com/foo/bar/pull/1](https://togithub.com/foo/bar/pull/1)'}
+  `(
+    '$input -> $output',
+    ({ input, output }: { input: string; output: string }) => {
+      expect(massageMarkdownLinks(input)).toEqual(output);
+    }
+  );
+});

lib/platform/github/massage-markdown-links.ts

@@ -0,0 +1,80 @@
+import type { Content } from 'mdast';
+import remark from 'remark';
+import type { Plugin, Transformer } from 'unified';
+import { logger } from '../../logger';
+import { hasKey } from '../../util/object';
+
+interface UrlMatch {
+  start: number;
+  end: number;
+  replaceTo: string;
+}
+
+const urlRegex =
+  /(?:https?:)?(?:\/\/)?(?:www\.)?(?<!api\.)(?:to)?github\.com\/[-_a-z0-9]+\/[-_a-z0-9]+\/(?:discussions|issues|pull)\/[0-9]+(?:#[-_a-z0-9]+)?/i;
+
+function massageLink(input: string): string {
+  return input.replace(/(?:to)?github\.com/i, 'togithub.com');
+}
+
+function collectLinkPosition(input: string, matches: UrlMatch[]): Plugin {
+  const transformer = (tree: Content): void => {
+    const startOffset: number = tree.position.start.offset;
+    const endOffset: number = tree.position.end.offset;
+
+    if (tree.type === 'link') {
+      const substr = input.slice(startOffset, endOffset);
+      const url: string = tree.url;
+      const offset: number = startOffset + substr.lastIndexOf(url);
+      if (urlRegex.test(url)) {
+        matches.push({
+          start: offset,
+          end: offset + url.length,
+          replaceTo: massageLink(url),
+        });
+      }
+    } else if (tree.type === 'text') {
+      let text: string = tree.value;
+      let match = urlRegex.exec(text);
+      let currentOffset = 0;
+      while (match) {
+        const [url] = match;
+
+        currentOffset += match.index;
+        const start = startOffset + currentOffset;
+
+        currentOffset += url.length;
+        const end = startOffset + currentOffset;
+
+        const newUrl = massageLink(url);
+        matches.push({ start, end, replaceTo: `[${url}](${newUrl})` });
+
+        text = text.slice(currentOffset);
+        match = urlRegex.exec(text);
+      }
+    } else if (hasKey('children', tree)) {
+      tree.children.forEach((child: Content) => {
+        transformer(child);
+      });
+    }
+  };
+
+  return () => transformer as Transformer;
+}
+
+export function massageMarkdownLinks(content: string): string {
+  try {
+    const rightSpaces = content.replace(content.trimRight(), '');
+    const matches: UrlMatch[] = [];
+    remark().use(collectLinkPosition(content, matches)).processSync(content);
+    const result = matches.reduceRight((acc, { start, end, replaceTo }) => {
+      const leftPart = acc.slice(0, start);
+      const rightPart = acc.slice(end);
+      return leftPart + replaceTo + rightPart;
+    }, content);
+    return result.trimRight() + rightSpaces;
+  } catch (err) /* istanbul ignore next */ {
+    logger.warn({ err }, `Unable to massage markdown text`);
+    return content;
+  }
+}