docs: validate relative links

.eslintrc.js

@@ -1,3 +1,5 @@
+const { jest } = require('@jest/globals');
+
 module.exports = {
   root: true,
   env: {
@@ -224,5 +226,14 @@ module.exports = {
         'import/extensions': 0,
       },
     },
+    {
+      files: ['tools/docs/test/**/*.mjs'],
+      env: {
+        jest: false,
+      },
+      rules: {
+        '@typescript-eslint/no-floating-promises': 0,
+      },
+    },
   ],
 };

.github/workflows/build.yml

@@ -558,6 +558,9 @@ jobs:
       - name: Build
         run: pnpm build:docs
 
+      - name: Test
+        run: pnpm test:docs
+
       - name: Upload
         uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
         with:

docs/usage/key-concepts/changelogs.md

@@ -98,11 +98,11 @@ If your repository uses the monorepo pattern make sure _each_ `package.json` fil
 
 ### maven package maintainers
 
-Read [`maven` datasource, making your changelogs fetchable](https://docs.renovatebot.com/modules/datasource/maven/#making-your-changelogs-fetchable).
+Read [`maven` datasource, making your changelogs fetchable](../modules/datasource/maven/index.md#making-your-changelogs-fetchable).
 
 ### Docker image maintainers
 
-Read the [Docker datasource](https://docs.renovatebot.com/modules/datasource/docker/) docs.
+Read the [Docker datasource](../modules/datasource/docker/index.md) docs.
 
 ### Nuget package maintainers
 

lib/modules/platform/gerrit/readme.md

@@ -42,7 +42,7 @@ It works similar to the default option `"pr"`.
 
 You can use the `statusCheckNames` configuration to map any of the available branch checks (like `minimumReleaseAge`, `mergeConfidence`, and so on) to a Gerrit label.
 
-For example, if you want to use the [Merge Confidence](https://docs.renovatebot.com/merge-confidence/) feature and map the result of the Merge Confidence check to your Gerrit label "Renovate-Merge-Confidence" you can configure:
+For example, if you want to use the [Merge Confidence](../../../merge-confidence.md) feature and map the result of the Merge Confidence check to your Gerrit label "Renovate-Merge-Confidence" you can configure:
 
 ```json
 {

package.json

@@ -51,6 +51,7 @@
     "test-e2e:install": "cd test/e2e && npm install --no-package-lock --prod",
     "test-e2e:run": "cd test/e2e && npm test",
     "test-schema": "run-s create-json-schema",
+    "test:docs": "node --test tools/docs/test/",
     "schedule-test-shards": "SCHEDULE_TEST_SHARDS=true ts-node jest.config.ts",
     "tsc": "tsc",
     "type-check": "run-s 'generate:*' 'tsc --noEmit {@}' --",
@@ -300,6 +301,7 @@
     "@types/semver-utils": "1.1.3",
     "@types/tar": "6.1.13",
     "@types/traverse": "0.6.36",
+    "@types/unist": "2.0.10",
     "@types/url-join": "4.0.3",
     "@types/validate-npm-package-name": "4.0.2",
     "@types/xmldoc": "1.1.9",

tools/docs/test/index.test.mjs

@@ -0,0 +1,78 @@
+import test from 'node:test';
+import fs from 'fs-extra';
+import { glob } from 'glob';
+import assert from 'node:assert';
+import MarkdownIt from 'markdown-it';
+import remark from 'remark';
+import path from 'node:path';
+
+const markdown = new MarkdownIt('zero');
+markdown.enable(['fence']);
+
+const root = path.resolve('tmp/docs');
+
+/**
+ * @param {any} node
+ * @param {Set<string>} files
+ * @param {string} file
+ */
+function checkNode(node, files, file) {
+  if (node.type === 'link') {
+    /** @type {import('mdast').Link} */
+    const link = node;
+    assert.ok(
+      !link.url.startsWith('/'),
+      'Link should be external or relative: ' + link.url,
+    );
+
+    if (link.url.startsWith('.')) {
+      const abs = path.resolve(
+        'tmp/docs',
+        path.dirname(file),
+        link.url.replace(/#.*/, ''),
+      );
+      // relative url
+      const target = abs.substring(root.length + 1);
+
+      assert.ok(
+        files.has(target),
+        `File not found: ${link.url} in ${file} -> ${target}`,
+      );
+    } else {
+      assert.ok(
+        !link.url.startsWith('https://docs.renovatebot.com/'),
+        'Docs links should be relative: ' + link.url,
+      );
+    }
+  } else if ('children' in node) {
+    for (const child of node.children) {
+      checkNode(child, files, file);
+    }
+  }
+}
+
+test('index', async (t) => {
+  await t.test('validate links', async (t) => {
+    const todo = await glob('**/*.md', { cwd: 'tmp/docs' });
+    const files = new Set(todo);
+
+    // add generated files
+    files.add('index.md');
+    files.add('release-notes-for-major-versions.md');
+    files.add('merge-confidence.md');
+
+    let c = 0;
+
+    for (const file of todo) {
+      c++;
+      await t.test(`${file}`, async () => {
+        const node = remark().parse(
+          await fs.readFile(`tmp/docs/${file}`, 'utf8'),
+        );
+        checkNode(node, files, file);
+      });
+    }
+
+    assert.ok(c > 0, 'Should find at least one file');
+  });
+});