verify existing redirects

Author: norareidy

.github/workflows/add-redirects.yml

@@ -1,63 +1,131 @@
-name: Add Redirects
+name: Verify Redirects
+
 on:
   pull_request_target:
+
 jobs:
-  add-redirects:
-    name: Get Redirects for Modified Files
+  verify-redirects:
+    name: Verifying Redirects
     runs-on: ubuntu-latest
+    env:
+      REDIRECTS_FILE: "config/redirects"
     permissions:
       pull-requests: write
     steps:
-      - uses: actions/checkout@v4
+      - name: Check Out Base Branch
+        uses: actions/checkout@v4
+
       - name: Get Changed Files
         id: changed-files
         uses: tj-actions/changed-files@c65cd883420fd2eb864698a825fc4162dd94482c
         with:
           include_all_old_new_renamed_files: true
-      - name: Make Redirects for Renamed Files
+
+      - name: Find Missing Redirects for Renamed Files
         id: renamed-files
         if: steps.changed-files.outputs.renamed_files_count > 0
         env:
           RENAMED_FILES: ${{ steps.changed-files.outputs.all_old_new_renamed_files }}
         run: |
-          renamed_redirects=""
+          renamed_redirects=()
           for file in $RENAMED_FILES; do
+
+            # only run for .txt files
             if [[ ! "$file" == *.txt ]]; then
               continue
             fi
+
+            # format old and new URLs
             old=$(echo "$file" | cut -d',' -f1)
             old="${old#source}"
             old="${old%.txt}"
             new=$(echo "$file" | cut -d',' -f2)
             new="${new#source}"
             new="${new%.txt}"
-            #single quotes = ${var} rendered literally; double quotes = $var interpreted
-            renamed_redirects+='<li>[&lt;v&gt;-*]: ${prefix}/${version}'"$old"'/ -> ${base}/${version}'"$new"'/</li>'
+            
+            # single quotes = ${var} rendered literally; double quotes = $var interpreted
+            renamed_redirect='${prefix}/${version}'"$old"'/ -> ${base}/${version}'"$new"'/'
+
+            # if redirect not already in file, add to array to add to PR description
+            if ! grep -q "$renamed_redirect" $REDIRECTS_FILE; then
+              renamed_redirects+=("$renamed_redirect")
+            fi
           done
           echo "redirects=${renamed_redirects}" >> "$GITHUB_OUTPUT"
-      - name: Make Redirects for Deleted Files
+
+      - name: Find Missing Redirects for Deleted Files
         id: deleted-files
         if: steps.changed-files.outputs.deleted_files_count > 0
         env:
           DELETED_FILES: ${{ steps.changed-files.outputs.deleted_files }}
         run: |
-          deleted_redirects=""
+          deleted_redirects=()
           for file in $DELETED_FILES; do
+
+            # only run for .txt files
             if [[ ! "$file" == *.txt ]]; then
               continue
             fi
+            
+            # format old URL
             old=$(echo "$file" | cut -d',' -f1)
             old="${old#source}"
             old="${old%.txt}"
-            deleted_redirects+='<li>[&lt;v&gt;-*]: ${prefix}/${version}'"$old"'/ -> ${base}/${version}/</li>'
+            
+            # single quotes = ${var} rendered literally; double quotes = $var interpreted
+            deleted_redirect='${prefix}/${version}'"$old"'/ -> ${base}/${version}/'
+                       
+            # if redirect not already in file, add to array to add to PR description
+            if ! grep -q "$deleted_redirect" $REDIRECTS_FILE; then  
+              deleted_redirects+=("$deleted_redirect")
+            fi
+
           done
           echo "redirects=${deleted_redirects}" >> "$GITHUB_OUTPUT"
+
+      - name: Build Redirect HTML
+        id: build-redirect-html
+        env:
+          RENAMED_REDIRECTS: ${{ steps.renamed-files.outputs.redirects }}
+          DELETED_REDIRECTS: ${{ steps.deleted-files.outputs.redirects }}
+        run: |
+          # empty string that stays empty if there are no redirects to suggest
+          redirect_html=""
+
+          for renamed_redirect in "${RENAMED_REDIRECTS[@]}"; do
+            redirect_html+="<li>[&lt;v&gt;-*]: $renamed_redirect</li>"
+          done
+
+          for deleted_redirect in "${DELETED_REDIRECTS[@]}"; do
+            redirect_html+="<li>[&lt;v&gt;-*]: $deleted_redirect</li>"
+          done
+
+          echo "redirect_html=${redirect_html}" >> "$GITHUB_OUTPUT"
+
       - name: Update PR Description
-        if: steps.changed-files.outputs.renamed_files_count > 0 || steps.changed-files.outputs.deleted_files_count > 0
+        if: steps.build-redirect-html.outputs.redirect_html
         uses: MongoCaleb/pr-description-action@4bdfe35b98f64532b419ad20b350a92546cd3aa1
+        env:
+          REDIRECT_HTML: ${{ steps.build-redirect-html.outputs.redirect_html }}
         with:
           regex: "- \\[ \\] Did you add redirects\\?.*"
           appendContentOnMatchOnly: false
           regexFlags: is
-          content: "- [ ] Did you add redirects?\n *Suggested redirects for moved/deleted files (replace &lt;v&gt; with earliest backport target version):*\n${{ steps.renamed-files.outputs.redirects }}${{ steps.deleted-files.outputs.redirects }}\n"
-          token: ${{ secrets.GITHUB_TOKEN }}
+          content: "- [ ] Did you add redirects?\n *Suggested redirects for moved/deleted files (replace &lt;v&gt; with earliest backport target version):*\n${{ steps.build-redirect-html.outputs.redirect_html }}\n"
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Check for duplicates in redirects file
+        run: |
+          # Specify the file to check  
+          file="$REDIRECTS_FILE"
+
+          if [[ -f "$file" ]]; then  
+            duplicates=$(sort "$file" | uniq -d)  
+            if [[ -n "$duplicates" ]]; then  
+              echo "Duplicate lines found in $file:"  
+              echo "$duplicates"  
+              exit 1 # error
+            fi
+          else  
+            echo "File $file does not exist. Skipping duplicate check."  
+          fi