feat(core): make broken link checker detect broken anchors - add onBrokenAnchors config

packages/docusaurus-mdx-loader/src/remark/transformLinks/__tests__/__snapshots__/index.test.ts.snap

@@ -12,17 +12,17 @@ exports[`transformAsset plugin pathname protocol 1`] = `
 exports[`transformAsset plugin transform md links to <a /> 1`] = `
 "[asset](https://example.com/asset.pdf)
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default} />
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default} />
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}>asset</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}>asset</a>
 
-in paragraph <a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}>asset</a>
+in paragraph <a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}>asset</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset (2).pdf").default}>asset with URL encoded chars</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset (2).pdf").default}>asset with URL encoded chars</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default + '#page=2'}>asset with hash</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default + '#page=2'}>asset with hash</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default} title="Title">asset</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default} title="Title">asset</a>
 
 [page](noUrl.md)
 
@@ -36,24 +36,24 @@ in paragraph <a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file
 
 [assets](/github/!file-loader!/assets.pdf)
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}>asset</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}>asset</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static2/asset2.pdf").default}>asset2</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static2/asset2.pdf").default}>asset2</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>staticAsset.pdf</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>staticAsset.pdf</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>@site/static/staticAsset.pdf</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>@site/static/staticAsset.pdf</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default + '#page=2'} title="Title">@site/static/staticAsset.pdf</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default + '#page=2'} title="Title">@site/static/staticAsset.pdf</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>Just staticAsset.pdf</a>, and <a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>**awesome** staticAsset 2.pdf 'It is really "AWESOME"'</a>, but also <a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>coded \`staticAsset 3.pdf\`</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>Just staticAsset.pdf</a>, and <a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>**awesome** staticAsset 2.pdf 'It is really "AWESOME"'</a>, but also <a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAsset.pdf").default}>coded \`staticAsset 3.pdf\`</a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAssetImage.png").default}><img alt="Clickable Docusaurus logo" src={require("!<PROJECT_ROOT>/node_modules/url-loader/dist/cjs.js?limit=10000&name=assets/images/[name]-[contenthash].[ext]&fallback=<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js!./static/staticAssetImage.png").default} width="200" height="200" /></a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/staticAssetImage.png").default}><img alt="Clickable Docusaurus logo" src={require("!<PROJECT_ROOT>/node_modules/url-loader/dist/cjs.js?limit=10000&name=assets/images/[name]-[contenthash].[ext]&fallback=<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js!./static/staticAssetImage.png").default} width="200" height="200" /></a>
 
-<a target="_blank" href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}><span style={{color: "red"}}>Stylized link to asset file</span></a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./asset.pdf").default}><span style={{color: "red"}}>Stylized link to asset file</span></a>
 
-<a target="_blank" href={require("./data.raw!=!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./data.json").default}>JSON</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("./data.raw!=!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./data.json").default}>JSON</a>
 
-<a target="_blank" href={require("./static/static-json.raw!=!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/static-json.json").default}>static JSON</a>
+<a target="_blank" data-noBrokenLinkCheck={true} href={require("./static/static-json.raw!=!<PROJECT_ROOT>/node_modules/file-loader/dist/cjs.js?name=assets/files/[name]-[contenthash].[ext]!./static/static-json.json").default}>static JSON</a>
 "
 `;

packages/docusaurus-mdx-loader/src/remark/transformLinks/index.ts

@@ -73,6 +73,34 @@ async function toAssetRequireNode(
     value: '_blank',
   });
 
+  // Assets are not routes, and are required by Webpack already
+  // They should not trigger the broken link checker
+  attributes.push({
+    type: 'mdxJsxAttribute',
+    name: 'data-noBrokenLinkCheck',
+    value: {
+      type: 'mdxJsxAttributeValueExpression',
+      value: 'true',
+      data: {
+        estree: {
+          type: 'Program',
+          body: [
+            {
+              type: 'ExpressionStatement',
+              expression: {
+                type: 'Literal',
+                value: true,
+                raw: 'true',
+              },
+            },
+          ],
+          sourceType: 'module',
+          comments: [],
+        },
+      },
+    },
+  });
+
   attributes.push({
     type: 'mdxJsxAttribute',
     name: 'href',

packages/docusaurus-module-type-aliases/src/index.d.ts

@@ -260,6 +260,15 @@ declare module '@docusaurus/useRouteContext' {
   export default function useRouteContext(): PluginRouteContext;
 }
 
+declare module '@docusaurus/useBrokenLinks' {
+  export type BrokenLinks = {
+    collectLink: (link: string) => void;
+    collectAnchor: (anchor: string) => void;
+  };
+
+  export default function useBrokenLinks(): BrokenLinks;
+}
+
 declare module '@docusaurus/useIsBrowser' {
   export default function useIsBrowser(): boolean;
 }

packages/docusaurus-theme-classic/src/theme/Heading/index.tsx

@@ -10,11 +10,13 @@ import clsx from 'clsx';
 import {translate} from '@docusaurus/Translate';
 import {useThemeConfig} from '@docusaurus/theme-common';
 import Link from '@docusaurus/Link';
+import useBrokenLinks from '@docusaurus/useBrokenLinks';
 import type {Props} from '@theme/Heading';
 
 import styles from './styles.module.css';
 
 export default function Heading({as: As, id, ...props}: Props): JSX.Element {
+  const brokenLinks = useBrokenLinks();
   const {
     navbar: {hideOnScroll},
   } = useThemeConfig();
@@ -23,6 +25,8 @@ export default function Heading({as: As, id, ...props}: Props): JSX.Element {
     return <As {...props} id={undefined} />;
   }
 
+  brokenLinks.collectAnchor(id);
+
   const anchorTitle = translate(
     {
       id: 'theme.common.headingLinkTitle',

packages/docusaurus-types/src/config.d.ts

@@ -143,6 +143,13 @@ export type DocusaurusConfig = {
    * @default "throw"
    */
   onBrokenLinks: ReportingSeverity;
+  /**
+   * The behavior of Docusaurus when it detects any broken link.
+   *
+   * @see https://docusaurus.io/docs/api/docusaurus-config#onBrokenAnchors
+   * @default "warn"
+   */
+  onBrokenAnchors: ReportingSeverity;
   /**
    * The behavior of Docusaurus when it detects any broken markdown link.
    *

packages/docusaurus-utils/src/__tests__/urlUtils.test.ts

@@ -18,6 +18,8 @@ import {
   buildSshUrl,
   buildHttpsUrl,
   hasSSHProtocol,
+  parseURLPath,
+  serializeURLPath,
 } from '../urlUtils';
 
 describe('normalizeUrl', () => {
@@ -232,6 +234,137 @@ describe('removeTrailingSlash', () => {
   });
 });
 
+describe('parseURLPath', () => {
+  it('parse and resolve pathname', () => {
+    expect(parseURLPath('')).toEqual({
+      pathname: '/',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/')).toEqual({
+      pathname: '/',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/page')).toEqual({
+      pathname: '/page',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/dir1/page')).toEqual({
+      pathname: '/dir1/page',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/dir1/dir2/./../page')).toEqual({
+      pathname: '/dir1/page',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/dir1/dir2/../..')).toEqual({
+      pathname: '/',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/dir1/dir2/../../..')).toEqual({
+      pathname: '/',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('./dir1/dir2./../page', '/dir3/dir4/page2')).toEqual({
+      pathname: '/dir3/dir4/dir1/page',
+      search: undefined,
+      hash: undefined,
+    });
+  });
+
+  it('parse query string', () => {
+    expect(parseURLPath('/page')).toEqual({
+      pathname: '/page',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/page?')).toEqual({
+      pathname: '/page',
+      search: '',
+      hash: undefined,
+    });
+    expect(parseURLPath('/page?test')).toEqual({
+      pathname: '/page',
+      search: 'test',
+      hash: undefined,
+    });
+    expect(parseURLPath('/page?age=42&great=true')).toEqual({
+      pathname: '/page',
+      search: 'age=42&great=true',
+      hash: undefined,
+    });
+  });
+
+  it('parse hash', () => {
+    expect(parseURLPath('/page')).toEqual({
+      pathname: '/page',
+      search: undefined,
+      hash: undefined,
+    });
+    expect(parseURLPath('/page#')).toEqual({
+      pathname: '/page',
+      search: undefined,
+      hash: '',
+    });
+    expect(parseURLPath('/page#anchor')).toEqual({
+      pathname: '/page',
+      search: undefined,
+      hash: 'anchor',
+    });
+  });
+
+  it('parse fancy real-world edge cases', () => {
+    expect(parseURLPath('/page?#')).toEqual({
+      pathname: '/page',
+      search: '',
+      hash: '',
+    });
+    expect(
+      parseURLPath('dir1/dir2/../page?age=42#anchor', '/dir3/page2'),
+    ).toEqual({
+      pathname: '/dir3/dir1/page',
+      search: 'age=42',
+      hash: 'anchor',
+    });
+  });
+});
+
+describe('serializeURLPath', () => {
+  function test(input: string, base?: string, expectedOutput?: string) {
+    expect(serializeURLPath(parseURLPath(input, base))).toEqual(
+      expectedOutput ?? input,
+    );
+  }
+
+  it('works for already resolved paths', () => {
+    test('/');
+    test('/dir1/page');
+    test('/dir1/page?');
+    test('/dir1/page#');
+    test('/dir1/page?#');
+    test('/dir1/page?age=42#anchor');
+  });
+
+  it('works for relative paths', () => {
+    test('', undefined, '/');
+    test('', '/dir1/dir2/page2', '/dir1/dir2/page2');
+    test('page', '/dir1/dir2/page2', '/dir1/dir2/page');
+    test('../page', '/dir1/dir2/page2', '/dir1/page');
+    test('/dir1/dir2/../page', undefined, '/dir1/page');
+    test(
+      '/dir1/dir2/../page?age=42#anchor',
+      undefined,
+      '/dir1/page?age=42#anchor',
+    );
+  });
+});
+
 describe('resolvePathname', () => {
   it('works', () => {
     // These tests are directly copied from https://github.com/mjackson/resolve-pathname/blob/master/modules/__tests__/resolvePathname-test.js

packages/docusaurus-utils/src/index.ts

@@ -48,13 +48,16 @@ export {
   encodePath,
   isValidPathname,
   resolvePathname,
+  parseURLPath,
+  serializeURLPath,
   addLeadingSlash,
   addTrailingSlash,
   removeTrailingSlash,
   hasSSHProtocol,
   buildHttpsUrl,
   buildSshUrl,
 } from './urlUtils';
+export type {URLPath} from './urlUtils';
 export {
   type Tag,
   type TagsListItem,

packages/docusaurus-utils/src/urlUtils.ts

@@ -165,14 +165,73 @@ export function isValidPathname(str: string): boolean {
   }
 }
 
+export type URLPath = {pathname: string; search?: string; hash?: string};
+
+// Let's name the concept of (pathname + search + hash) as URLPath
+// See also https://twitter.com/kettanaito/status/1741768992866308120
+// Note: this function also resolves relative pathnames while parsing!
+export function parseURLPath(urlPath: string, fromPath?: string): URLPath {
+  function parseURL(url: string, base?: string | URL): URL {
+    try {
+      // A possible alternative? https://github.com/unjs/ufo#url
+      return new URL(url, base ?? 'https://example.com');
+    } catch (e) {
+      throw new Error(
+        `Can't parse URL ${url}${base ? ` with base ${base}` : ''}`,
+        {cause: e},
+      );
+    }
+  }
+
+  const base = fromPath ? parseURL(fromPath) : undefined;
+  const url = parseURL(urlPath, base);
+
+  const {pathname} = url;
+
+  // Fixes annoying url.search behavior
+  // "" => undefined
+  // "?" => ""
+  // "?param => "param"
+  const search = url.search
+    ? url.search.slice(1)
+    : urlPath.includes('?')
+    ? ''
+    : undefined;
+
+  // Fixes annoying url.hash behavior
+  // "" => undefined
+  // "#" => ""
+  // "?param => "param"
+  const hash = url.hash
+    ? url.hash.slice(1)
+    : urlPath.includes('#')
+    ? ''
+    : undefined;
+
+  return {
+    pathname,
+    search,
+    hash,
+  };
+}
+
+export function serializeURLPath(urlPath: URLPath): string {
+  const search = urlPath.search === undefined ? '' : `?${urlPath.search}`;
+  const hash = urlPath.hash === undefined ? '' : `#${urlPath.hash}`;
+  return `${urlPath.pathname}${search}${hash}`;
+}
+
 /**
  * Resolve pathnames and fail-fast if resolution fails. Uses standard URL
  * semantics (provided by `resolve-pathname` which is used internally by React
  * router)
  */
 export function resolvePathname(to: string, from?: string): string {
+  // TODO do we really need resolve-pathname lib anymore?
+  //  possible alternative: decodeURI(parseURLPath(to, from).pathname);
   return resolvePathnameUnsafe(to, from);
 }
+
 /** Appends a leading slash to `str`, if one doesn't exist. */
 export function addLeadingSlash(str: string): string {
   return addPrefix(str, '/');