Attribute the re-applied PR for squash revert-of-revert commits

src/extractors.test.ts

@@ -810,6 +810,18 @@ describe("extractPullRequestNumbersForCommit", () => {
     expect(result).toEqual([]);
   });
 
+  // A squash revert-of-revert re-applies the change, so its PR is attributed like a normal
+  // merge; a plain (or triple) revert removes it and is skipped. Keyed on revert depth parity,
+  // since squash messages (`Revert "Revert "…"" (#N)`) carry the nesting in the title, not a branch.
+  it.each([
+    ['Revert "Title" (#79504)', [], "plain squash revert (odd depth)"],
+    ['Revert "Revert "Title"" (#79620)', [79620], "squash revert-of-revert (even depth)"],
+    ['Revert "Revert "Revert "Title""" (#5)', [], "triple squash revert (odd depth)"],
+  ])("message %j should yield %j (%s)", (message, expected) => {
+    const result = extractPullRequestNumbersForCommit({ sha: "abc", message });
+    expect(result).toEqual(expected);
+  });
+
   // Numbers above the GraphQL Int (32-bit) bound cannot be GitHub PR numbers
   // and must be filtered so they don't poison the release sync mutation.
   it.each([

src/extractors.ts

@@ -303,9 +303,10 @@ export function extractPullRequestNumbersForCommit(commit: CommitContext): numbe
 
   const rawMessage = commit.message ?? "";
 
-  // Reverts reference the original PR, not a new one.
-  if (/^Revert "/i.test(rawMessage)) {
-    verbose(`Skipping revert commit ${commit.sha} with message: "${rawMessage}"`);
+  // Odd depth = a net revert; its `(#N)` is the revert's own PR, undoing prior work, so skip it.
+  // Even depth (revert-of-revert) re-applies the change and must attribute its PR like a normal merge.
+  if (leadingRevertDepth(rawMessage) % 2 === 1) {
+    verbose(`Skipping odd-depth revert commit ${commit.sha} with message: "${rawMessage}"`);
     return [];
   }
   if (getRevertBranchDepth(commit.branchName) % 2 === 1) {
@@ -453,6 +454,21 @@ export function getRevertMessageDepth(message: string | null | undefined): numbe
   return parseRevertMessage(message).depth;
 }
 
+/**
+ * Count leading `Revert "` wrappers. Unlike {@link getRevertMessageDepth} this does not
+ * require balanced quotes on the subject line, so a revert whose quoted title spans
+ * multiple lines (e.g. reverting a GitLab merge commit) still counts as depth 1.
+ */
+function leadingRevertDepth(message: string): number {
+  let text = message;
+  let depth = 0;
+  while (/^Revert "/i.test(text)) {
+    depth++;
+    text = text.replace(/^Revert "/i, "");
+  }
+  return depth;
+}
+
 /** Extract identifiers being reverted. Returns [] if not an odd-depth revert. */
 export function extractRevertedIssueIdentifiersForCommit(commit: CommitContext): ExtractedIdentifier[] {
   if (!commit) return [];