Better revert detection

src/extractors.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it } from "vitest";
-import { extractLinearIssueIdentifiersForCommit, extractPullRequestNumbersForCommit } from "./extractors";
+import {
+  extractLinearIssueIdentifiersForCommit,
+  extractPullRequestNumbersForCommit,
+  getRevertBranchDepth,
+  getRevertMessageDepth,
+} from "./extractors";
 import { CommitContext } from "./types";
 
 describe("extractLinearIssueIdentifiersForCommit", () => {
@@ -88,7 +93,7 @@ describe("extractLinearIssueIdentifiersForCommit", () => {
   });
 });
 
-describe("version suffix handling ", () => {
+describe("version suffix handling", () => {
   // Version strings should NOT match
   it.each([
     ["release/ios-1.57.1", []],
@@ -124,7 +129,7 @@ describe("version suffix handling ", () => {
   });
 });
 
-describe("leading zero rejection ", () => {
+describe("leading zero rejection", () => {
   it("rejects LIN-0004 style identifiers", () => {
     const result = extractLinearIssueIdentifiersForCommit({
       sha: "abc",
@@ -135,8 +140,7 @@ describe("leading zero rejection ", () => {
   });
 });
 
-describe("underscore handling ", () => {
-  // Underscores act as word boundaries
+describe("underscore handling", () => {
   it.each([
     ["story/LIN-123_LIN-321_hello_world", ["LIN-123", "LIN-321"]],
     ["username/lin-123_branch_name", ["LIN-123"]],
@@ -150,7 +154,7 @@ describe("underscore handling ", () => {
   });
 });
 
-describe("multiple identifiers ", () => {
+describe("multiple identifiers", () => {
   it.each([
     ["Fixes LIN-123 and LIN-321", ["LIN-123", "LIN-321"]],
     ["Closes LIN-123, LIN-321", ["LIN-123", "LIN-321"]],
@@ -411,6 +415,50 @@ describe("revert branch handling", () => {
     });
     expect(result).toEqual([]);
   });
+
+  it("blocks add-extraction from message-only revert with magic word", () => {
+    const result = extractLinearIssueIdentifiersForCommit({
+      sha: "abc",
+      branchName: null,
+      message: 'Revert "Fixes ENG-100"',
+    });
+    expect(result).toEqual([]);
+  });
+
+  it("allows extraction from revert-of-revert branch (even depth)", () => {
+    const result = extractLinearIssueIdentifiersForCommit({
+      sha: "abc",
+      branchName: "revert-572-revert-571-romain/bac-39",
+      message: null,
+    });
+    expect(result).toEqual(["BAC-39"]);
+  });
+});
+
+describe("getRevertBranchDepth", () => {
+  it.each([
+    [null, 0],
+    ["romain/bac-39", 0],
+    ["revert-571-romain/bac-39", 1],
+    ["revert-572-revert-571-romain/bac-39", 2],
+    ["revert-574-revert-573-revert-572-romain/bac-39", 3],
+    ["org/revert-572-revert-571-romain/bac-39", 2],
+  ])("branch %j → depth %d", (branch, expected) => {
+    expect(getRevertBranchDepth(branch)).toBe(expected);
+  });
+});
+
+describe("getRevertMessageDepth", () => {
+  it.each([
+    [null, 0],
+    ["Fix memory leak", 0],
+    ['Revert "DRIVE-320: Fix"', 1],
+    ['Revert "Revert "DRIVE-320: Fix""', 2],
+    ['Revert "Revert "Revert "DRIVE-320: Fix"""', 3],
+    ['Reapply "DRIVE-320: Fix"', 0],
+  ])("message %j → depth %d", (message, expected) => {
+    expect(getRevertMessageDepth(message)).toBe(expected);
+  });
 });
 
 describe("extractPullRequestNumbersForCommit", () => {

src/extractors.ts

@@ -134,19 +134,23 @@ export function extractLinearIssueIdentifiersForCommit(commit: CommitContext): s
     return [];
   }
 
-  // GitHub auto-generates branch names like "revert-571-romain/bac-39" for revert PRs.
-  // Block extraction to prevent the original issue identifier from being added to the release.
-  if (/(^|\/)revert-\d+-/i.test(commit.branchName ?? "")) {
-    log(`Skipping revert branch ${commit.branchName} for commit ${commit.sha}`);
+  // Odd depth = the commit is undoing previous work (a revert), so we must not
+  // count its identifiers as "added". Even depth = revert-of-revert (re-add).
+  const { depth: branchDepth, inner: strippedBranch } = parseRevertBranch(commit.branchName ?? "");
+  if (branchDepth % 2 === 1) {
+    log(`Skipping revert branch "${commit.branchName}" (depth ${branchDepth}) for commit ${commit.sha}`);
+    return [];
+  }
+  const { depth: messageDepth } = parseRevertMessage(commit.message ?? "");
+  if (messageDepth % 2 === 1) {
+    log(`Skipping revert message (depth ${messageDepth}) for commit ${commit.sha}`);
     return [];
   }
 
   const found = new Map<string, string>();
 
-  // Branch name: extract all matches (branch names are always intentional)
-  const branchName = commit.branchName ?? "";
-  if (branchName.length > 0) {
-    for (const match of matchAllIdentifiers(branchName)) {
+  if (strippedBranch.length > 0) {
+    for (const match of matchAllIdentifiers(strippedBranch)) {
       if (!found.has(match.identifier)) {
         found.set(match.identifier, match.rawIdentifier);
       }
@@ -179,8 +183,9 @@ export function extractPullRequestNumbersForCommit(commit: CommitContext): numbe
     return [];
   }
 
-  // Skip merge commits of revert PRs — branch name like "revert-571-romain/bac-39"
-  if (/(^|\/)revert-\d+-/i.test(commit.branchName ?? "")) {
+  // Revert merge commits reference the original PR number, not a new one.
+  // Even depth (revert-of-revert) falls through to normal extraction.
+  if (getRevertBranchDepth(commit.branchName) % 2 === 1) {
     log(`Skipping revert merge commit ${commit.sha}`);
     return [];
   }
@@ -213,3 +218,45 @@ export function extractPullRequestNumbersForCommit(commit: CommitContext): numbe
 
   return [...new Set(prNumbers)];
 }
+
+function parseRevertBranch(branchName: string): { depth: number; inner: string } {
+  // Full refs can have org/ prefixes (e.g. "org/revert-571-..."), strip to the revert pattern.
+  // Non-greedy so we stop at the first revert-N- match, not the last (preserves nested depth).
+  let name = branchName.replace(/^.*?\/(?=revert-\d+-)/i, "");
+  let depth = 0;
+  while (/^revert-\d+-/i.test(name)) {
+    name = name.replace(/^revert-\d+-/i, "");
+    depth++;
+  }
+  return { depth, inner: name };
+}
+
+/**
+ * Strip revert-N- prefixes from a branch name and count nesting depth.
+ * e.g. "revert-572-revert-571-romain/bac-39" → { depth: 2, inner: "romain/bac-39" }
+ */
+export function getRevertBranchDepth(branchName: string | null | undefined): number {
+  if (!branchName) return 0;
+  return parseRevertBranch(branchName).depth;
+}
+
+function parseRevertMessage(message: string): { depth: number; inner: string } {
+  let text = message;
+  let depth = 0;
+  while (/^Revert "/i.test(text)) {
+    const match = text.match(/^Revert "(.+)"(.*)$/s);
+    if (!match) break;
+    text = match[1]!;
+    depth++;
+  }
+  return { depth, inner: text };
+}
+
+/**
+ * Unwrap Revert "..." layers from a commit message and count nesting depth.
+ * e.g. 'Revert "Revert "DRIVE-320: Fix""' → { depth: 2, inner: "DRIVE-320: Fix" }
+ */
+export function getRevertMessageDepth(message: string | null | undefined): number {
+  if (!message) return 0;
+  return parseRevertMessage(message).depth;
+}