fix(webui): validate inferred file paths before preview (#4935)

webui/src/tests/api.test.ts

@@ -5,6 +5,7 @@ import {
   createModelConfiguration,
   deleteSession,
   fetchFilePreview,
+  fetchFilePreviewAvailability,
   fetchAutomations,
   fetchApiService,
   fetchCliApps,
@@ -102,6 +103,32 @@ describe("webui API helpers", () => {
     );
   });
 
+  it("probes file preview availability without requesting contents", async () => {
+    await expect(
+      fetchFilePreviewAvailability("tok", "websocket:chat-1", "notes/ready.md"),
+    ).resolves.toBe(true);
+
+    expect(fetch).toHaveBeenCalledWith(
+      "/api/sessions/websocket%3Achat-1/file-preview?path=notes%2Fready.md&probe=1",
+      expect.objectContaining({
+        headers: { Authorization: "Bearer tok" },
+        credentials: "same-origin",
+      }),
+    );
+  });
+
+  it("returns false when a file preview probe is unavailable", async () => {
+    vi.mocked(fetch).mockResolvedValueOnce({
+      ok: true,
+      status: 200,
+      json: async () => ({ available: false }),
+    } as Response);
+
+    await expect(
+      fetchFilePreviewAvailability("tok", "websocket:chat-1", "notes/missing.md"),
+    ).resolves.toBe(false);
+  });
+
   it("percent-encodes websocket keys when fetching session automations", async () => {
     await fetchSessionAutomations("tok", "websocket:chat-1");
 

webui/src/tests/markdown-text-renderer.test.tsx

@@ -1,6 +1,7 @@
-import { fireEvent, render, screen } from "@testing-library/react";
+import { act, fireEvent, render, screen, waitFor } from "@testing-library/react";
 import { describe, expect, it, vi } from "vitest";
 
+import { FilePreviewAvailabilityProvider } from "@/components/FilePreviewAvailabilityContext";
 import MarkdownTextRenderer from "@/components/MarkdownTextRenderer";
 
 describe("MarkdownTextRenderer", () => {
@@ -34,6 +35,75 @@ describe("MarkdownTextRenderer", () => {
     );
   });
 
+  it("keeps unavailable inferred inline file paths non-interactive", async () => {
+    const onOpenFilePreview = vi.fn();
+    const resolve = vi.fn().mockResolvedValue(false);
+    render(
+      <FilePreviewAvailabilityProvider resolve={resolve}>
+        <MarkdownTextRenderer onOpenFilePreview={onOpenFilePreview}>
+          {"Future file: `notes/missing.md`"}
+        </MarkdownTextRenderer>
+      </FilePreviewAvailabilityProvider>,
+    );
+
+    const reference = screen.getByTestId("inline-file-path");
+    expect(reference).toHaveTextContent("missing.md");
+    await waitFor(() => expect(resolve).toHaveBeenCalledWith("notes/missing.md"));
+    expect(reference).not.toHaveAttribute("role");
+    expect(reference).not.toHaveAttribute("tabindex");
+
+    fireEvent.click(reference);
+
+    expect(onOpenFilePreview).not.toHaveBeenCalled();
+  });
+
+  it("keeps inferred inline file paths non-interactive when availability lookup fails", async () => {
+    const onOpenFilePreview = vi.fn();
+    let rejectAvailability!: (reason?: unknown) => void;
+    const resolve = vi.fn(() => new Promise<boolean>((_resolve, reject) => {
+      rejectAvailability = reject;
+    }));
+    render(
+      <FilePreviewAvailabilityProvider resolve={resolve}>
+        <MarkdownTextRenderer onOpenFilePreview={onOpenFilePreview}>
+          {"Unreadable file: `notes/locked.md`"}
+        </MarkdownTextRenderer>
+      </FilePreviewAvailabilityProvider>,
+    );
+
+    const reference = screen.getByTestId("inline-file-path");
+    await waitFor(() => expect(resolve).toHaveBeenCalledWith("notes/locked.md"));
+    await act(async () => {
+      rejectAvailability(new Error("probe failed"));
+      await Promise.resolve();
+    });
+
+    expect(reference).not.toHaveAttribute("role");
+    expect(reference).not.toHaveAttribute("tabindex");
+    fireEvent.click(reference);
+    expect(onOpenFilePreview).not.toHaveBeenCalled();
+  });
+
+  it("makes available inferred inline file paths previewable", async () => {
+    const onOpenFilePreview = vi.fn();
+    const resolve = vi.fn().mockResolvedValue(true);
+    render(
+      <FilePreviewAvailabilityProvider resolve={resolve}>
+        <MarkdownTextRenderer onOpenFilePreview={onOpenFilePreview}>
+          {"Existing file: `notes/ready.md`"}
+        </MarkdownTextRenderer>
+      </FilePreviewAvailabilityProvider>,
+    );
+
+    const reference = screen.getByTestId("inline-file-path");
+    await waitFor(() => expect(reference).toHaveAttribute("role", "button"));
+    expect(reference).toHaveAttribute("tabindex", "0");
+
+    fireEvent.click(reference);
+
+    expect(onOpenFilePreview).toHaveBeenCalledWith("notes/ready.md");
+  });
+
   it("does not treat non-file hrefs as previews just because the label looks like a file", () => {
     const onOpenFilePreview = vi.fn();
     render(

webui/src/tests/thread-shell.test.tsx

@@ -231,6 +231,59 @@ describe("ThreadShell", () => {
     );
   });
 
+  it("keeps inferred file paths non-interactive when the availability probe fails", async () => {
+    const client = makeClient();
+    let resolveProbe!: (value: Response) => void;
+    const probe = new Promise<Response>((resolve) => {
+      resolveProbe = resolve;
+    });
+    const fetchMock = vi.fn((input: RequestInfo | URL) => {
+      const url = String(input);
+      if (url.includes("websocket%3Apreview-error/webui-thread")) {
+        return Promise.resolve(httpJson(transcriptFromSimpleMessages([
+          { role: "assistant", content: "Unreadable file: `prompts/dream.md`" },
+        ])));
+      }
+      if (url.includes("websocket%3Apreview-error/file-preview?")) return probe;
+      return Promise.resolve({
+        ok: false,
+        status: 404,
+        json: async () => ({}),
+      });
+    });
+    vi.stubGlobal("fetch", fetchMock);
+
+    render(wrap(
+      client,
+      <ThreadShell
+        session={session("preview-error")}
+        title="Preview error"
+        onToggleSidebar={() => {}}
+      />,
+    ));
+
+    const reference = await screen.findByTestId("inline-file-path");
+    await waitFor(() => expect(fetchMock).toHaveBeenCalledWith(
+      expect.stringContaining("file-preview?path=prompts%2Fdream.md&probe=1"),
+      expect.anything(),
+    ));
+    await act(async () => {
+      resolveProbe({
+        ok: false,
+        status: 500,
+        text: async () => "failed to read file",
+        json: async () => ({}),
+      } as Response);
+      await probe;
+      await Promise.resolve();
+    });
+
+    expect(reference).not.toHaveAttribute("role");
+    expect(reference).not.toHaveAttribute("tabindex");
+    fireEvent.click(reference);
+    expect(screen.queryByText("failed to read file")).not.toBeInTheDocument();
+  });
+
   it("does not navigate away when clicking the chat title", async () => {
     const client = makeClient();
     const onGoHome = vi.fn();