CCM-8881: Use custom merge script to combine changes from both repos

Author: m-houston

scripts/githooks/merge.js

@@ -0,0 +1,66 @@
+const fs = require("fs");
+
+// Read files
+const [file1, file2] = process.argv.slice(2);
+const lines1 = fs.readFileSync(file1).toString().split('\n');
+const lines2 = fs.readFileSync(file2).toString().split('\n');
+
+// Tokenize lines in file1 for later comparison
+const tokenize = line => {
+  if (line === '') {
+    return [];
+  }
+  return line.split(/\s+/).filter(x => x !== '#').slice(0, 1);
+};
+const lines1Tokens = lines1.flatMap(tokenize);
+
+// Step through the files
+let pos1 = 0, pos2 = 0;
+while (pos1 < lines1.length || pos2 < lines2.length) {
+
+  const l1 = pos1 < lines1.length && lines1[pos1] || '';
+  const l2 = pos2 < lines2.length && lines2[pos2] || '';
+
+  // If the lines match, print l1 and skip l2
+  if (l1 !== '' && l1 === l2) {
+    process.stdout.write(`${l1}\n`);
+    pos1++;
+    pos2++;
+    continue;
+  }
+
+  if (pos2 < lines2.length) {
+    // If l2 is empty, skip l2
+    if (l2 === '') {
+      pos2++;
+      continue;
+    }
+
+    const [l2token] = tokenize(l2);
+
+    // If l2 token matches l1 token, print l1
+    if (pos1 < lines1.length && lines1Tokens[pos1] === l2token) {
+      process.stdout.write(`${l1}\n`);
+      pos1++;
+      pos2++;
+      continue;
+    }
+
+    // If l2 doesn't match any lines in file1, print l2
+    if (l2token && !lines1Tokens.includes(l2token)) {
+      process.stdout.write(`${l2}\n`);
+    }
+    pos2++
+    continue;
+  }
+
+  // If we're not at the end of file1, print l1
+  if (pos1 < lines1.length) {
+    if (pos1 === lines1.length - 1 && l1 === '') {
+      // Don't print tailing newline
+    } else {
+      process.stdout.write(`${l1}\n`);
+    }
+    pos1++;
+  }
+}

scripts/githooks/sync-template-repo.sh

@@ -5,14 +5,16 @@ set -euo pipefail
 # Script to synchronise the nhs-notify-template-repository with this repository
 #
 # Usage:
-#   $ [options] ./check-terraform-format.sh
+#   $ [options] ./sync-template-repo.sh
 #
 # Options:
 #   new_only=true      # Only identify new files from the template-repository
 #   changes_only=true  # Only identify files which have drifted from the template-repository
 
 # ==============================================================================
 
+scriptdir=$(realpath "$(dirname "$0")")
+
 # Command line parameters
 new_only=${new_only:-false}
 changes_only=${changes_only:-false}
@@ -108,17 +110,9 @@ while IFS= read -r -d '' file; do
       if ! diff -q "$file" "$target_path" > /dev/null 2>&1; then
         if is_merge "$relative_path"; then
           echo "Merging changes from $relative_path"
-          cp "$target_path" "${target_path}.bak"
-          if git merge-file "$target_path" /dev/null "$file" --union; then
-              if ! cmp -s "$target_path" "${target_path}.bak"; then
-                  FILES_WITH_CHANGES+=("${relative_path}")
-              fi
-          else
-              echo "Merge failed for $relative_path, rolling back."
-              mv "${target_path}.bak" "$target_path"
-              diff3 "$target_path" /dev/null "$file"
-          fi
-          rm -f "${target_path}.bak"
+          echo node "$(dirname "$0")/merge.js" "$target_path" "$file"
+          node "${scriptdir}/merge.js" "$target_path" "$file" > "$target_path.merged"
+          mv "$target_path.merged" "$target_path"
         else
           echo "Copying changes from $relative_path"
           cp "$file" "$target_path"