fix(web): keep linked PR handoffs in current thread

apps/web/src/components/ChatView.tsx

@@ -168,7 +168,10 @@ import {
   selectThreadPreviewMiniPlayer,
   usePreviewMiniPlayerStore,
 } from "../previewMiniPlayerStore";
-import { isThreadOwnPullRequest } from "./pullRequest/pullRequestDetail.logic";
+import {
+  isThreadOwnPullRequest,
+  pullRequestOwnershipCandidate,
+} from "./pullRequest/pullRequestDetail.logic";
 import { PullRequestDetailPanel } from "./pullRequest/PullRequestDetailPanel";
 import { PullRequestDetailGhost } from "./pullRequest/PullRequestGhosts";
 import { PullRequestsUnavailableState } from "./pullRequest/PullRequestsUnavailableState";
@@ -7074,11 +7077,14 @@ function ChatViewContent(props: ChatViewProps) {
         }}
         context={
           isThreadOwnPullRequest(
-            {
-              projectId: linkedThreadPullRequest?.projectId ?? activeProject?.id ?? null,
-              repository: threadRepository,
-              number: activeThreadPr?.number ?? null,
-            },
+            pullRequestOwnershipCandidate({
+              linked: linkedThreadPullRequest,
+              inferred: {
+                projectId: activeProject?.id ?? null,
+                repository: activeProjectRepository,
+                number: activeThreadPr?.number ?? null,
+              },
+            }),
             {
               projectId: activeRightPanelSurface.projectId,
               repository: activeRightPanelSurface.repository,

apps/web/src/components/pullRequest/pullRequestDetail.logic.test.ts

@@ -28,6 +28,7 @@ import {
   pullRequestComposerTarget,
   pullRequestFindingKey,
   pullRequestHandoffLabels,
+  pullRequestOwnershipCandidate,
   pullRequestReviewOutcome,
   readableFailure,
   shouldRefreshPullRequestActivity,
@@ -1186,6 +1187,20 @@ describe("how the branch stands against its base", () => {
 describe("whether the panel is showing the thread's own pull request", () => {
   const surface = { projectId: "proj-a", repository: "acme/app", number: 7 };
 
+  it("uses the persisted link while inferred pull request detail is unavailable", () => {
+    expect(
+      pullRequestOwnershipCandidate({
+        linked: { projectId: "linked-project", repository: "acme/app", number: 7 },
+        inferred: { projectId: "proj-a", repository: "acme/app", number: null },
+      }),
+    ).toEqual({
+      projectId: "linked-project",
+      repository: "acme/app",
+      number: 7,
+      explicitlyLinked: true,
+    });
+  });
+
   it("matches on project, repository and number together", () => {
     expect(
       isThreadOwnPullRequest({ projectId: "proj-a", repository: "acme/app", number: 7 }, surface),
@@ -1198,13 +1213,47 @@ describe("whether the panel is showing the thread's own pull request", () => {
     ).toBe(false);
   });
 
+  it("keeps every agent handoff in an explicitly linked thread after its project id changes", () => {
+    const ownsPullRequest = isThreadOwnPullRequest(
+      {
+        projectId: "linked-project",
+        repository: "acme/app",
+        number: 7,
+        explicitlyLinked: true,
+      },
+      surface,
+    );
+    const composerTarget = { environmentId: "env-1", threadId: "thread-1" };
+
+    expect(ownsPullRequest).toBe(true);
+    expect(pullRequestComposerTarget(ownsPullRequest ? "thread" : "page", composerTarget)).toBe(
+      composerTarget,
+    );
+    expect(pullRequestHandoffLabels(ownsPullRequest)).toEqual({
+      fixFinding: "Fix in this thread",
+      fixCheck: "Fix in this thread",
+      fixFindings: "Fix findings in this thread",
+    });
+  });
+
   it("rejects another repository or another number", () => {
     expect(
       isThreadOwnPullRequest({ projectId: "proj-a", repository: "acme/web", number: 7 }, surface),
     ).toBe(false);
     expect(
       isThreadOwnPullRequest({ projectId: "proj-a", repository: "acme/app", number: 8 }, surface),
     ).toBe(false);
+    expect(
+      isThreadOwnPullRequest(
+        {
+          projectId: "linked-project",
+          repository: "acme/web",
+          number: 7,
+          explicitlyLinked: true,
+        },
+        surface,
+      ),
+    ).toBe(false);
   });
 
   it("rejects a thread with no project or no pull request of its own", () => {

apps/web/src/components/pullRequest/pullRequestDetail.logic.ts

@@ -16,6 +16,22 @@ import type {
 
 import { inferReviewCommentFenceLanguage, type ReviewCommentContext } from "~/reviewCommentContext";
 
+interface PullRequestOwnershipIdentity {
+  readonly projectId: string | null;
+  readonly repository: string | null;
+  readonly number: number | null;
+}
+
+/** Prefer the persisted link even while its live host detail is unavailable. */
+export function pullRequestOwnershipCandidate(input: {
+  readonly linked: PullRequestOwnershipIdentity | null;
+  readonly inferred: PullRequestOwnershipIdentity;
+}): PullRequestOwnershipIdentity & { readonly explicitlyLinked: boolean } {
+  return input.linked
+    ? { ...input.linked, explicitlyLinked: true }
+    : { ...input.inferred, explicitlyLinked: false };
+}
+
 /** Activity changes only when the same host resource reports a newer revision. */
 export function shouldRefreshPullRequestActivity(
   previous: { readonly key: string; readonly updatedAt: string } | null,
@@ -55,6 +71,8 @@ export function isThreadOwnPullRequest(
     readonly projectId: string | null;
     readonly repository: string | null;
     readonly number: number | null;
+    /** An explicit thread link owns this PR even if its project was recreated or remapped. */
+    readonly explicitlyLinked?: boolean;
   },
   surface: {
     readonly projectId: string;
@@ -63,9 +81,9 @@ export function isThreadOwnPullRequest(
   },
 ): boolean {
   return (
-    thread.projectId === surface.projectId &&
     thread.repository === surface.repository &&
-    thread.number === surface.number
+    thread.number === surface.number &&
+    (thread.explicitlyLinked === true || thread.projectId === surface.projectId)
   );
 }