trunk-merge/pr-3432/5a5d3058-75a1-49d1-86b1-bbc34bf44948

packages/core/src/code-review/reviewPrompts.test.ts

@@ -3,6 +3,7 @@ import { describe, expect, it } from "vitest";
 import {
   buildAskAboutPrCommentPrompt,
   buildBatchedInlineCommentsPrompt,
+  buildChatAboutPrCommentPrompt,
   buildFixPrCommentPrompt,
   buildInlineCommentPrompt,
 } from "./reviewPrompts";
@@ -65,7 +66,7 @@ describe("buildBatchedInlineCommentsPrompt", () => {
   });
 });
 
-describe("buildFixPrCommentPrompt / buildAskAboutPrCommentPrompt", () => {
+describe("PR comment prompts", () => {
   it("includes the thread body and side", () => {
     const out = buildFixPrCommentPrompt("a.ts", 4, "new", [
       makeComment("please rename"),
@@ -81,4 +82,19 @@ describe("buildFixPrCommentPrompt / buildAskAboutPrCommentPrompt", () => {
     ]);
     expect(out).toContain("Do not make any changes");
   });
+
+  it("chat prompt includes the thread and custom message", () => {
+    const out = buildChatAboutPrCommentPrompt(
+      'src/a".ts',
+      8,
+      "new",
+      [makeComment("consider extracting this", "reviewer")],
+      "Is there already a helper for this?",
+    );
+    expect(out).toContain('<file path="src/a&quot;.ts" />');
+    expect(out).toContain("line 8 (new)");
+    expect(out).toContain("@reviewer");
+    expect(out).toContain("consider extracting this");
+    expect(out.endsWith("Is there already a helper for this?")).toBe(true);
+  });
 });

packages/core/src/code-review/reviewPrompts.ts

@@ -15,6 +15,17 @@ function formatThreadForPrompt(comments: PrReviewComment[]): string {
   return comments.map((c) => `@${c.user.login}:\n> ${c.body}`).join("\n\n");
 }
 
+function formatPrCommentPromptContext(
+  filePath: string,
+  line: number,
+  side: "old" | "new",
+  comments: PrReviewComment[],
+): string {
+  const escapedPath = escapeXmlAttr(filePath);
+  const thread = formatThreadForPrompt(comments);
+  return `<file path="${escapedPath}" />, line ${line} (${side}):\n\n${thread}`;
+}
+
 function formatLineRef(startLine: number, endLine: number): string {
   return startLine === endLine
     ? `line ${startLine}`
@@ -85,9 +96,8 @@ export function buildFixPrCommentPrompt(
   side: "old" | "new",
   comments: PrReviewComment[],
 ): string {
-  const escapedPath = escapeXmlAttr(filePath);
-  const thread = formatThreadForPrompt(comments);
-  return `Fix this PR review comment on <file path="${escapedPath}" />, line ${line} (${side}):\n\n${thread}`;
+  const context = formatPrCommentPromptContext(filePath, line, side, comments);
+  return `Fix this PR review comment on ${context}`;
 }
 
 export function buildAskAboutPrCommentPrompt(
@@ -96,7 +106,17 @@ export function buildAskAboutPrCommentPrompt(
   side: "old" | "new",
   comments: PrReviewComment[],
 ): string {
-  const escapedPath = escapeXmlAttr(filePath);
-  const thread = formatThreadForPrompt(comments);
-  return `Help me understand this PR review comment on <file path="${escapedPath}" />, line ${line} (${side}):\n\n${thread}\n\nWhat is this comment asking for and how should I address it? Do not make any changes, your job is simply to chat with me about this comment. If I need further changes, I'll ask.`;
+  const context = formatPrCommentPromptContext(filePath, line, side, comments);
+  return `Help me understand this PR review comment on ${context}\n\nWhat is this comment asking for and how should I address it? Do not make any changes, your job is simply to chat with me about this comment. If I need further changes, I'll ask.`;
+}
+
+export function buildChatAboutPrCommentPrompt(
+  filePath: string,
+  line: number,
+  side: "old" | "new",
+  comments: PrReviewComment[],
+  message: string,
+): string {
+  const context = formatPrCommentPromptContext(filePath, line, side, comments);
+  return `Regarding this PR review comment on ${context}\n\n${message}`;
 }

packages/ui/src/features/code-review/components/PatchedFileDiff.test.tsx

@@ -0,0 +1,82 @@
+import type { FileDiffMetadata } from "@pierre/diffs";
+import type { PrCommentThread } from "@posthog/core/code-review/types";
+import type { ChangedFile } from "@posthog/shared/domain-types";
+import { render, screen } from "@testing-library/react";
+import type { ReactNode } from "react";
+import { describe, expect, it, vi } from "vitest";
+
+vi.mock("../../../primitives/FileIcon", () => ({
+  FileIcon: () => <span data-testid="file-icon" />,
+}));
+
+vi.mock("./InteractiveFileDiff", () => ({
+  InteractiveFileDiff: ({
+    fileDiff,
+    renderCustomHeader,
+  }: {
+    fileDiff: FileDiffMetadata;
+    renderCustomHeader: (fileDiff: FileDiffMetadata) => ReactNode;
+  }) => renderCustomHeader(fileDiff),
+}));
+
+import { PatchedFileDiff } from "./PatchedFileDiff";
+
+const patch = `diff --git a/src/reviewed.ts b/src/reviewed.ts
+index 1111111..2222222 100644
+--- a/src/reviewed.ts
++++ b/src/reviewed.ts
+@@ -1 +1 @@
+-before
++after`;
+
+describe.each([
+  [
+    "regular",
+    {
+      path: "src/reviewed.ts",
+      originalPath: "src/original.ts",
+      patch,
+    },
+  ],
+  ["binary", { path: "assets/reviewed.png", patch: null }],
+  ["unavailable", { path: "src/unavailable.ts", patch: null }],
+] as const)("PatchedFileDiff %s header", (_kind, fileInput) => {
+  it("renders metadata before line change stats", () => {
+    const file = {
+      ...fileInput,
+      linesAdded: 2,
+      linesRemoved: 1,
+    } as ChangedFile;
+    const threadPath = file.originalPath ?? file.path;
+    const commentThreads = new Map<number, PrCommentThread>([
+      [
+        1,
+        {
+          rootId: 1,
+          nodeId: "thread-1",
+          isResolved: false,
+          filePath: threadPath,
+          comments: [{ id: 1 }, { id: 2 }] as PrCommentThread["comments"],
+        },
+      ],
+    ]);
+
+    render(
+      <PatchedFileDiff
+        file={file}
+        taskId="task"
+        options={{}}
+        collapsed
+        onToggle={() => {}}
+        commentThreads={commentThreads}
+      />,
+    );
+
+    const header = screen.getByRole("button");
+    const text = header.textContent ?? "";
+    const additions = _kind === "regular" ? "+1" : "+2";
+
+    expect(screen.getByTitle("2 comments")).toBeInTheDocument();
+    expect(text.indexOf("2 comments")).toBeLessThan(text.indexOf(additions));
+  });
+});

packages/ui/src/features/code-review/components/PatchedFileDiff.tsx

@@ -49,6 +49,7 @@ export function PatchedFileDiff({
     }
     return null;
   }, [fileDiff, fallback, file.path]);
+  const commentCount = countPrCommentsForFile(commentThreads, file);
 
   // Branch/PR diffs have no reliable local working-tree file to preview (the
   // checkout may be on a different ref, and GitHub omits binary patches), so
@@ -63,6 +64,7 @@ export function PatchedFileDiff({
         collapsed={collapsed}
         onToggle={onToggle}
         externalUrl={externalUrl}
+        commentCount={commentCount}
         headerTrailing={headerTrailing}
       />
     );
@@ -78,6 +80,7 @@ export function PatchedFileDiff({
         collapsed={collapsed}
         onToggle={onToggle}
         externalUrl={externalUrl}
+        commentCount={commentCount}
         headerTrailing={headerTrailing}
       />
     );
@@ -95,9 +98,26 @@ export function PatchedFileDiff({
           fileDiff={fd}
           collapsed={collapsed}
           onToggle={onToggle}
+          commentCount={commentCount}
           trailing={headerTrailing}
         />
       )}
     />
   );
 }
+
+function countPrCommentsForFile(
+  threads: Map<number, PrCommentThread> | undefined,
+  file: Pick<ChangedFile, "path" | "originalPath">,
+): number {
+  let count = 0;
+  for (const thread of threads?.values() ?? []) {
+    if (
+      thread.filePath === file.path ||
+      (file.originalPath != null && thread.filePath === file.originalPath)
+    ) {
+      count += thread.comments.length;
+    }
+  }
+  return count;
+}

packages/ui/src/features/code-review/components/PrCommentThread.test.tsx

@@ -0,0 +1,154 @@
+import type { PrReviewComment } from "@posthog/shared";
+import { Theme } from "@radix-ui/themes";
+import { render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { PrCommentMetadata } from "../types";
+import { PrCommentThread } from "./PrCommentThread";
+
+const { reply, resolve, sendPromptToAgent } = vi.hoisted(() => ({
+  reply: vi.fn(),
+  resolve: vi.fn(),
+  sendPromptToAgent: vi.fn(),
+}));
+
+vi.mock("../hooks/usePrCommentActions", () => ({
+  usePrCommentActions: () => ({ reply, resolve }),
+}));
+
+vi.mock("../../sessions/sendPromptToAgent", () => ({ sendPromptToAgent }));
+
+function makeComment(): PrReviewComment {
+  return {
+    id: 42,
+    body: "Could this use the shared helper?",
+    created_at: "2026-07-14T12:00:00Z",
+    user: {
+      login: "reviewer",
+      avatar_url: "",
+    },
+  } as PrReviewComment;
+}
+
+function makeMetadata(): PrCommentMetadata {
+  return {
+    kind: "pr-comment",
+    threadId: 42,
+    nodeId: "thread-node",
+    isResolved: false,
+    comments: [makeComment()],
+    isOutdated: false,
+    isFileLevel: false,
+    startLine: 8,
+    endLine: 8,
+    side: "additions",
+  };
+}
+
+function renderThread() {
+  return render(
+    <Theme>
+      <PrCommentThread
+        taskId="task-1"
+        prUrl="https://github.com/PostHog/posthog/pull/1"
+        filePath="src/example.ts"
+        metadata={makeMetadata()}
+      />
+    </Theme>,
+  );
+}
+
+describe("PrCommentThread", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    reply.mockResolvedValue(true);
+    resolve.mockResolvedValue(true);
+    sendPromptToAgent.mockResolvedValue(true);
+  });
+
+  it("sends a custom chat message with the review context", async () => {
+    const user = userEvent.setup();
+    renderThread();
+
+    await user.click(screen.getByRole("button", { name: "Chat" }));
+    await user.type(
+      screen.getByPlaceholderText("Ask the agent about this comment..."),
+      "Check whether this helper already exists",
+    );
+    await user.click(screen.getByRole("button", { name: "Send" }));
+
+    expect(sendPromptToAgent).toHaveBeenCalledWith(
+      "task-1",
+      expect.stringContaining("Could this use the shared helper?"),
+    );
+    expect(sendPromptToAgent).toHaveBeenCalledWith(
+      "task-1",
+      expect.stringContaining("Check whether this helper already exists"),
+    );
+    await waitFor(() =>
+      expect(
+        screen.queryByPlaceholderText("Ask the agent about this comment..."),
+      ).not.toBeInTheDocument(),
+    );
+  });
+
+  it("keeps the custom message available when sending fails", async () => {
+    sendPromptToAgent.mockResolvedValue(false);
+    const user = userEvent.setup();
+    renderThread();
+
+    await user.click(screen.getByRole("button", { name: "Chat" }));
+    const textarea = screen.getByPlaceholderText(
+      "Ask the agent about this comment...",
+    );
+    await user.type(textarea, "Keep this draft");
+    await user.click(screen.getByRole("button", { name: "Send" }));
+
+    await waitFor(() =>
+      expect(
+        screen.getByPlaceholderText("Ask the agent about this comment..."),
+      ).toHaveValue("Keep this draft"),
+    );
+  });
+
+  it("keeps a reply composer opened while a chat message is sending", async () => {
+    let resolveSend: ((success: boolean) => void) | undefined;
+    sendPromptToAgent.mockReturnValue(
+      new Promise<boolean>((resolve) => {
+        resolveSend = resolve;
+      }),
+    );
+    const user = userEvent.setup();
+    renderThread();
+
+    await user.click(screen.getByRole("button", { name: "Chat" }));
+    await user.type(
+      screen.getByPlaceholderText("Ask the agent about this comment..."),
+      "Check this",
+    );
+    await user.click(screen.getByRole("button", { name: "Send" }));
+    await user.click(screen.getByRole("button", { name: "Close composer" }));
+    await user.click(screen.getByRole("button", { name: "Reply" }));
+    await user.type(screen.getByPlaceholderText("Write a reply..."), "Keep me");
+
+    resolveSend?.(true);
+
+    await waitFor(() =>
+      expect(screen.getByPlaceholderText("Write a reply...")).toHaveValue(
+        "Keep me",
+      ),
+    );
+  });
+
+  it("still posts replies without sending them to chat", async () => {
+    const user = userEvent.setup();
+    renderThread();
+
+    await user.click(screen.getByRole("button", { name: "Reply" }));
+    await user.type(screen.getByPlaceholderText("Write a reply..."), "Done");
+    await user.click(screen.getByRole("button", { name: "Reply" }));
+
+    expect(reply).toHaveBeenCalledWith(42, "Done");
+    expect(sendPromptToAgent).not.toHaveBeenCalled();
+  });
+});