From 812570799d3db3c94bb0484ebac349d83baab2d0 Mon Sep 17 00:00:00 2001
From: Howard Edwards <howarde.edwards@gmail.com>
Date: Mon, 25 Sep 2023 09:28:23 -0500
Subject: [PATCH 1/3] Check if any of the known page ids include the hash being
 checked for

---
 scripts/link-checker.js | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/scripts/link-checker.js b/scripts/link-checker.js
index 2cf249d217..001149f9ad 100644
--- a/scripts/link-checker.js
+++ b/scripts/link-checker.js
@@ -227,7 +227,7 @@ async function checkLinks() {
 
         let matchesHash = true;
         if (hash) {
-          matchesHash = !!matchingPage?.ids.includes(hash);
+          matchesHash = !!matchingPage?.ids.some((id) => id.includes(hash));
         }
 
         const isLinkBroken = !(
@@ -274,7 +274,11 @@ async function checkLinks() {
             hrefOrSrc.match(pattern)
           );
 
-        if (!isHashCheckingDisabled && hash && !pageData.ids.includes(hash)) {
+        if (
+          !isHashCheckingDisabled &&
+          hash &&
+          !pageData.ids.some((id) => id.includes(hash))
+        ) {
           consoleError(
             `Found broken external link on ${htmlPath}:${lineNumber}:${columnNumber}, ` +
               'hash not found on page'

From 56d93dbc56487d3dfbe11c948a5b63f993dda70a Mon Sep 17 00:00:00 2001
From: Howard Edwards <howarde.edwards@gmail.com>
Date: Mon, 25 Sep 2023 13:10:52 -0500
Subject: [PATCH 2/3] Include clarifying comment

---
 scripts/link-checker.js | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/scripts/link-checker.js b/scripts/link-checker.js
index 001149f9ad..aeab461e74 100644
--- a/scripts/link-checker.js
+++ b/scripts/link-checker.js
@@ -227,6 +227,15 @@ async function checkLinks() {
 
         let matchesHash = true;
         if (hash) {
+          // On some websites, the ids may not exactly match the hash included
+          // in the link.
+          // For e.g. GitHub will prepend client facing ids with their own
+          // calculated value. A heading in a README for example could be
+          // Foo bar, navigated to with https://github.com/foo/bar#foo-bar,
+          // but GitHub calculates the actual markup id included in the document
+          // as being user-content-foo-bar for its own page processing purposes.
+          //
+          // See https://github.com/w3c/aria-practices/issues/2809
           matchesHash = !!matchingPage?.ids.some((id) => id.includes(hash));
         }
 

From be464a0c140ba5dd1bfae80462109c8640f65031 Mon Sep 17 00:00:00 2001
From: Howard Edwards <howarde.edwards@gmail.com>
Date: Mon, 2 Oct 2023 09:38:29 -0400
Subject: [PATCH 3/3] Set up cases where unique hashes need to be handled

---
 .link-checker.js        |  9 ++++++++-
 scripts/link-checker.js | 34 +++++++++++++++++++++++-----------
 2 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/.link-checker.js b/.link-checker.js
index d3a1ff3fda..2377e0ef6a 100644
--- a/.link-checker.js
+++ b/.link-checker.js
@@ -11,9 +11,16 @@ module.exports = {
       '.carousel-image a',
     ],
   },
+  hashCheckHandlers: [
+    {
+      name: 'github',
+      pattern: /^https:\/\/github\.com\/.*/,
+      matchHash: (ids, hash) =>
+        ids.includes(hash) || ids.includes(`user-content-${hash}`),
+    },
+  ],
   ignoreHashesOnExternalPagesMatchingRegex: [
     // Some hash links are resolved with JS and are therefore difficult to check algorithmically
-    /^https:\/\/github\.com\/.*\/wiki\//,
     /^https:\/\/html\.spec\.whatwg\.org\/multipage\//,
   ],
 };
diff --git a/scripts/link-checker.js b/scripts/link-checker.js
index aeab461e74..f8c8649cc0 100644
--- a/scripts/link-checker.js
+++ b/scripts/link-checker.js
@@ -33,6 +33,23 @@ async function checkLinks() {
     return getLineNumber;
   };
 
+  const checkPathForHash = (hrefOrSrc, ids = [], hash) => {
+    // On some websites, the ids may not exactly match the hash included
+    // in the link.
+    // For e.g. GitHub will prepend client facing ids with their own
+    // calculated value. A heading in a README for example could be
+    // 'Foo bar', navigated to with https://github.com/foo/bar#foo-bar,
+    // but GitHub calculates the actual markup id included in the document
+    // as being 'user-content-foo-bar' for its own page processing purposes.
+    //
+    // See https://github.com/w3c/aria-practices/issues/2809
+    const handler = options.hashCheckHandlers.find(({ pattern }) =>
+      pattern.test(hrefOrSrc)
+    );
+    if (handler) return handler.matchHash(ids, hash);
+    else return ids.includes(hash);
+  };
+
   const countConsoleErrors = () => {
     let errorCount = 0;
 
@@ -227,16 +244,11 @@ async function checkLinks() {
 
         let matchesHash = true;
         if (hash) {
-          // On some websites, the ids may not exactly match the hash included
-          // in the link.
-          // For e.g. GitHub will prepend client facing ids with their own
-          // calculated value. A heading in a README for example could be
-          // Foo bar, navigated to with https://github.com/foo/bar#foo-bar,
-          // but GitHub calculates the actual markup id included in the document
-          // as being user-content-foo-bar for its own page processing purposes.
-          //
-          // See https://github.com/w3c/aria-practices/issues/2809
-          matchesHash = !!matchingPage?.ids.some((id) => id.includes(hash));
+          matchesHash = !!checkPathForHash(
+            pathMinusHash,
+            matchingPage?.ids,
+            hash
+          );
         }
 
         const isLinkBroken = !(
@@ -286,7 +298,7 @@ async function checkLinks() {
         if (
           !isHashCheckingDisabled &&
           hash &&
-          !pageData.ids.some((id) => id.includes(hash))
+          !checkPathForHash(hrefOrSrc, pageData.ids, hash)
         ) {
           consoleError(
             `Found broken external link on ${htmlPath}:${lineNumber}:${columnNumber}, ` +