restore legacy redirect handling needed for (internal docs) links

Author: sarahs

lib/redirects/get-old-paths-from-permalink.js

@@ -1,44 +1,106 @@
-const { latest } = require('../enterprise-server-releases')
+const { latest, deprecated, lastReleaseWithLegacyFormat } = require('../enterprise-server-releases')
 const { getPathWithoutLanguage, getPathWithLanguage, getVersionStringFromPath } = require('../path-utils')
+const patterns = require('../patterns')
+const versionSatisfiesRange = require('../version-satisfies-range')
 const currentlySupportedVersions = Object.keys(require('../all-versions'))
 const nonEnterpriseDefaultVersion = require('../non-enterprise-default-version')
 
 // This function takes a current path, applies what we know about historically
 // supported paths, and returns an array of ALL possible associated old
 // paths that users might try to hit.
-module.exports = function getOldPathsFromPath (currentPath, languageCode) {
+module.exports = function getOldPathsFromPath (currentPath, languageCode, currentVersion) {
   const oldPaths = new Set()
 
   const versionFromPath = getVersionStringFromPath(currentPath)
 
-  // The following only applies to Dotcom paths.
-  // Create old path /free-pro-team@latest/github from new path /github (or from a frontmatter `redirect_from` path like /articles)
-  if (versionFromPath === 'homepage' || !currentlySupportedVersions.includes(versionFromPath) || (versionFromPath === nonEnterpriseDefaultVersion && !currentPath.includes(nonEnterpriseDefaultVersion))) {
+  // This only applies to Dotcom paths, so no need to determine whether the version is deprecated
+  // create old path /free-pro-team@latest/github from new path /github (or from a frontmatter `redirect_from` path like /articles)
+  if (versionFromPath === 'homepage' || !(currentlySupportedVersions.includes(versionFromPath) || deprecated.includes(versionFromPath)) || (versionFromPath === nonEnterpriseDefaultVersion && !currentPath.includes(nonEnterpriseDefaultVersion))) {
     oldPaths.add(currentPath
       .replace(`/${languageCode}`, `/${languageCode}/${nonEnterpriseDefaultVersion}`))
   }
 
-  oldPaths.add(currentPath
-    .replace(/\/enterprise-server@(\d)/, '/enterprise/$1'))
+  // ------ BEGIN LEGACY VERSION FORMAT REPLACEMENTS ------//
+  // These remain relevant to handle legacy-formatted frontmatter redirects
+  // and archived versions paths.
 
-  // create old path /enterprise/<version>/user from new path /enterprise-server@<version>/github
+  // create old path /insights from current path /enterprise/version/insights
   oldPaths.add(currentPath
-    .replace(/\/enterprise-server@(\d.+?)\/github/, '/enterprise/$1/user'))
+    .replace(`/${languageCode}/enterprise/${latest}/user/insights`, '/insights'))
 
-  // create old path /insights from new path /enterprise-server@<latest>/insights
-  oldPaths.add(currentPath
-    .replace(`/enterprise-server@${latest}/insights`, '/insights'))
+  // create old path /desktop/guides from current path /desktop
+  // create old path /admin/guides from current path /admin
+  if (!currentPath.includes('/guides')) {
+    oldPaths.add(currentPath
+      .replace('/desktop', '/desktop/guides')
+      .replace('/admin', '/admin/guides'))
+  }
+
+  // create old path /user from current path /user/github on 2.16+ only
+  if (currentlySupportedVersions.includes(currentVersion) || versionSatisfiesRange(currentVersion, '>2.15')) {
+    oldPaths.add(currentPath
+      .replace('/user/github', '/user'))
+  }
 
-  // create old path /admin from new path /enterprise-server@<latest>/admin
+  // create old path /enterprise from current path /enterprise/latest
   oldPaths.add(currentPath
-    .replace(`/enterprise-server@${latest}/admin`, '/admin'))
+    .replace(`/enterprise/${latest}`, '/enterprise'))
+
+  // create old path /enterprise/foo from current path /enterprise/user/foo
+  // this supports old developer paths like /enterprise/webhooks with no /user in them
+  if (currentPath.includes('/enterprise/')) {
+    oldPaths.add(currentPath
+      .replace('/user/', '/'))
+  }
 
-  // create old path /enterprise from new path /enterprise-server@<latest>
+  // create old path /enterprise/foo from current path /enterprise/latest/user/foo
   oldPaths.add(currentPath
-    .replace(`/enterprise-server@${latest}`, '/enterprise'))
+    .replace(`/enterprise/${latest}/user/`, '/enterprise/'))
+
+  // ------ END LEGACY VERSION FORMAT REPLACEMENTS ------//
+
+  // ------ BEGIN MODERN VERSION FORMAT REPLACEMENTS ------//
+  if (currentlySupportedVersions.includes(currentVersion) || versionSatisfiesRange(currentVersion, `>${lastReleaseWithLegacyFormat}`)) {
+    (new Set(oldPaths)).forEach(oldPath => {
+      // create old path /enterprise/<version> from new path /enterprise-server@<version>
+      oldPaths.add(oldPath
+        .replace(/\/enterprise-server@(\d)/, '/enterprise/$1'))
+
+      // create old path /enterprise/<version>/user from new path /enterprise-server@<version>/github
+      oldPaths.add(oldPath
+        .replace(/\/enterprise-server@(\d.+?)\/github/, '/enterprise/$1/user'))
+
+      // create old path /insights from new path /enterprise-server@<latest>/insights
+      oldPaths.add(oldPath
+        .replace(`/enterprise-server@${latest}/insights`, '/insights'))
+
+      // create old path /admin from new path /enterprise-server@<latest>/admin
+      oldPaths.add(oldPath
+        .replace(`/enterprise-server@${latest}/admin`, '/admin'))
+
+      // create old path /enterprise from new path /enterprise-server@<latest>
+      oldPaths.add(oldPath
+        .replace(`/enterprise-server@${latest}`, '/enterprise'))
+
+      // create old path /enterprise-server from new path /enterprise-server@<latest>
+      oldPaths.add(oldPath
+        .replace(`/enterprise-server@${latest}`, '/enterprise-server'))
+
+      if (!patterns.adminProduct.test(oldPath)) {
+        // create old path /enterprise/<version>/user/foo from new path /enterprise-server@<version>/foo
+        oldPaths.add(currentPath
+          .replace(/\/enterprise-server@(\d.+?)\//, '/enterprise/$1/user/'))
+
+        // create old path /enterprise/user/foo from new path /enterprise-server@<latest>/foo
+        oldPaths.add(currentPath
+          .replace(`/enterprise-server@${latest}/`, '/enterprise/user/'))
+      }
+    })
+  }
+  // ------ END MODERN VERSION FORMAT REPLACEMENTS ------//
 
   // For each old path added to the set above, do the following...
-  oldPaths.forEach(oldPath => {
+  (new Set(oldPaths)).forEach(oldPath => {
     // for English only, remove language code
     if (languageCode === 'en') {
       oldPaths.add(getPathWithoutLanguage(oldPath))