Add PR switch cwd regression test

Author: backnotprop

packages/server/review-agent-cwd.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, test } from "bun:test";
+import { resolveReviewScopedAgentCwd } from "./review";
+
+describe("resolveReviewScopedAgentCwd", () => {
+  test("uses the current PR pool checkout in PR mode", () => {
+    const worktreePool = {
+      resolve: (url: string) => url === "https://example.com/pr/2" ? "/tmp/pr-2" : undefined,
+    };
+
+    expect(resolveReviewScopedAgentCwd({
+      isPRMode: true,
+      prUrl: "https://example.com/pr/2",
+      worktreePool,
+      agentCwd: "/tmp/original-pr",
+      currentDiffType: "uncommitted",
+      gitContextCwd: "/repo",
+    })).toBe("/tmp/pr-2");
+  });
+
+  test("does not reuse the previous PR checkout when a switched PR has no pool entry", () => {
+    const worktreePool = {
+      resolve: () => undefined,
+    };
+
+    expect(resolveReviewScopedAgentCwd({
+      isPRMode: true,
+      prUrl: "https://example.com/pr/other-repo",
+      worktreePool,
+      agentCwd: "/tmp/original-pr",
+      currentDiffType: "uncommitted",
+      gitContextCwd: "/repo",
+    })).toBeUndefined();
+  });
+
+  test("keeps non-PR local review fallback behavior", () => {
+    expect(resolveReviewScopedAgentCwd({
+      isPRMode: false,
+      agentCwd: "/tmp/local-review",
+      currentDiffType: "uncommitted",
+      gitContextCwd: "/repo",
+    })).toBe("/tmp/local-review");
+
+    expect(resolveReviewScopedAgentCwd({
+      isPRMode: false,
+      currentDiffType: "uncommitted",
+      gitContextCwd: "/repo",
+    })).toBe("/repo");
+  });
+});

packages/server/review.ts

@@ -130,6 +130,24 @@ export interface ReviewSession {
   dispose: () => void;
 }
 
+export interface ResolveReviewScopedAgentCwdOptions {
+  isPRMode: boolean;
+  prUrl?: string;
+  worktreePool?: Pick<import("@plannotator/shared/worktree-pool").WorktreePool, "resolve">;
+  agentCwd?: string;
+  currentDiffType: DiffType;
+  gitContextCwd?: string;
+}
+
+export function resolveReviewScopedAgentCwd(
+  options: ResolveReviewScopedAgentCwdOptions,
+): string | undefined {
+  if (options.isPRMode && options.prUrl && options.worktreePool) {
+    return options.worktreePool.resolve(options.prUrl);
+  }
+  return options.agentCwd ?? resolveVcsCwd(options.currentDiffType, options.gitContextCwd);
+}
+
 // --- Server Implementation ---
 
 const MAX_RETRIES = 5;
@@ -190,10 +208,14 @@ export async function createReviewSession(
   // Agent jobs — background process manager (late-binds serverUrl via getter)
   let serverUrl = "";
   const resolveScopedAgentCwd = (): string | undefined => {
-    if (isPRMode && prMetadata && options.worktreePool) {
-      return options.worktreePool.resolve(prMetadata.url);
-    }
-    return options.agentCwd ?? resolveVcsCwd(currentDiffType, gitContext?.cwd);
+    return resolveReviewScopedAgentCwd({
+      isPRMode,
+      prUrl: prMetadata?.url,
+      worktreePool: options.worktreePool,
+      agentCwd: options.agentCwd,
+      currentDiffType,
+      gitContextCwd: gitContext?.cwd,
+    });
   };
   const resolveAgentCwd = (): string => {
     return resolveScopedAgentCwd() ?? cwd;