Fix breadcrumbs when paths have partial match 🍞 (github#22414)

* Add failing breadcrumb test for paths with partial match

* Handle overlapping paths when creating breadcrumbs

middleware/contextualizers/breadcrumbs.js

@@ -31,15 +31,11 @@ async function getBreadcrumbs(
   intendedLanguage
 ) {
   // Find the page that starts with the requested path
-  let childPage = pageArray.find((page) =>
-    currentPathWithoutLanguage.startsWith(page.href.slice(3))
-  )
+  let childPage = findPageWithPath(currentPathWithoutLanguage, pageArray)
 
   // Find the page in the fallback page array (likely the English sub-tree)
   const fallbackChildPage =
-    (fallbackPageArray || []).find((page) => {
-      return currentPathWithoutLanguage.startsWith(page.href.slice(3))
-    }) || childPage
+    findPageWithPath(currentPathWithoutLanguage, fallbackPageArray || []) || childPage
 
   // No matches, we bail
   if (!childPage && !fallbackChildPage) {
@@ -74,3 +70,34 @@ async function getBreadcrumbs(
     return [breadcrumb]
   }
 }
+
+// Finds the page that starts with or equals the requested path in the array of
+// pages e.g. if the current page is /actions/learn-github-actions/understanding-github-actions,
+// depending on the pages in the pageArray agrument, would find:
+//
+// * /actions
+// * /actions/learn-github-actions
+// * /actions/learn-github-actions/understanding-github-actions
+function findPageWithPath(pageToFind, pageArray) {
+  return pageArray.find((page) => {
+    const pageWithoutLanguage = page.href.slice(3)
+    const numPathSegments = pageWithoutLanguage.split('/').length
+    const pageToFindNumPathSegments = pageToFind.split('/').length
+
+    if (pageToFindNumPathSegments > numPathSegments) {
+      // if the current page to find has more path segments, add a trailing
+      // slash to the page comparison to avoid an overlap like:
+      //
+      // * /github-cli/github-cli/about-github-cli with /github
+      return pageToFind.startsWith(`${pageWithoutLanguage}/`)
+    } else if (pageToFindNumPathSegments === numPathSegments) {
+      // if the current page has the same number of path segments, only match
+      // if the paths are the same to avoid an overlap like:
+      //
+      // * /get-started/using-github with /get-started/using-git
+      return pageToFind === pageWithoutLanguage
+    } else {
+      return false
+    }
+  })
+}

tests/rendering/breadcrumbs.js

@@ -57,6 +57,19 @@ describe('breadcrumbs', () => {
       expect($breadcrumbs[0].attribs.title).toBe('product: Billing and payments')
     })
 
+    test('works for pages that have overlapping product names', async () => {
+      const $ = await getDOM(
+        // article path has overlap with `/en/github`
+        '/en/github-cli/github-cli/about-github-cli'
+      )
+      const $breadcrumbs = $('[data-testid=breadcrumbs] a')
+      console.log(`dbg: breadcrumbs`, $breadcrumbs)
+      expect($breadcrumbs).toHaveLength(3)
+      expect($breadcrumbs[0].attribs.title).toBe('product: GitHub CLI')
+      expect($breadcrumbs[1].attribs.title).toBe('category: GitHub CLI')
+      expect($breadcrumbs[2].attribs.title).toBe('article: About GitHub CLI')
+    })
+
     test('parses Liquid variables inside titles', async () => {
       const $ = await getDOM('/en/enterprise/admin/enterprise-support')
       const $breadcrumbs = $('[data-testid=breadcrumbs] a')