fix(observation): validate document consistency with bounded identity checks

apps/extension/src/browser-driver/__tests__/chromium-cdp.test.ts

@@ -29,6 +29,24 @@ function fakeApi() {
 }
 
 describe("ChromiumCdp", () => {
+  it("changes attachment identity only across real debugger attachments", async () => {
+    const { api, onEvent, onDetach } = fakeApi();
+    const cdp = new ChromiumCdp(api);
+    expect(cdp.getAttachmentId(4)).toBeUndefined();
+    await cdp.ensureAttached(4);
+    const first = cdp.getAttachmentId(4);
+    expect(first).toBeTruthy();
+    await cdp.ensureAttached(4);
+    onEvent.fire({ tabId: 4 }, "Target.attachedToTarget", { sessionId: "child" });
+    expect(cdp.getAttachmentId(4)).toBe(first);
+    onDetach.fire({ tabId: 4 }, "target_closed");
+    expect(cdp.getAttachmentId(4)).toBeUndefined();
+    await cdp.ensureAttached(4);
+    expect(cdp.getAttachmentId(4)).not.toBe(first);
+    await cdp.detach(4);
+    expect(cdp.getAttachmentId(4)).toBeUndefined();
+  });
+
   it("discovers multiple iframe targets and recursively routes nested OOPIF commands", async () => {
     const { api, onEvent } = fakeApi();
     (api.sendCommand as ReturnType<typeof vi.fn>).mockImplementation(

apps/extension/src/browser-driver/__tests__/frame-graph.test.ts

@@ -2,6 +2,24 @@ import { describe, expect, it } from "vitest";
 import { buildFrameGraph, type CdpFrameTreeNode, type CdpFrameTreeSource } from "../frame-graph";
 
 describe("buildFrameGraph", () => {
+  it("preserves the owning target's loader identity", () => {
+    const graph = buildFrameGraph([
+      {
+        target: { tabId: 4 },
+        tree: {
+          frame: { id: "root", loaderId: "root-loader" },
+          childFrames: [{ frame: { id: "child", loaderId: "stale-placeholder" } }],
+        },
+      },
+      {
+        target: { tabId: 4, sessionId: "child-session" },
+        tree: { frame: { id: "child", loaderId: "child-loader" } },
+      },
+    ]);
+    expect(graph?.frames.find((frame) => frame.frameId === "root")?.loaderId).toBe("root-loader");
+    expect(graph?.frames.find((frame) => frame.frameId === "child")?.loaderId).toBe("child-loader");
+  });
+
   it("keeps sibling frames distinct and routes nested OOPIFs to their child sessions", () => {
     const graph = buildFrameGraph([
       {

apps/extension/src/browser-driver/chromium-cdp.ts

@@ -164,6 +164,7 @@ async function settleBeforeDeadline(promises: Promise<void>[], deadline: number)
 export class ChromiumCdp {
   private readonly api: CdpDebuggerApi;
   private readonly attachedTabs = new Set<number>();
+  private readonly attachmentIds = new Map<number, string>();
   private readonly attachInFlight = new Map<number, Promise<void>>();
   private readonly detachInFlight = new Map<number, Promise<void>>();
   private readonly tabOwners = new Map<number, Set<string>>();
@@ -198,6 +199,11 @@ export class ChromiumCdp {
     this.bindFrameTargetHandler();
   }
 
+  /** Identity of this actual debugger attachment, independent of frame topology. */
+  getAttachmentId(tabId: number): string | undefined {
+    return this.attachmentIds.get(tabId);
+  }
+
   /** Attach to `tabId` if we haven't already in this driver. */
   async ensureAttached(tabId: number): Promise<void> {
     // Returning a tab clears the cache before Chrome finishes detaching.
@@ -217,6 +223,7 @@ export class ChromiumCdp {
         await this.enableConsoleDomains(tabId);
         await this.enableNetworkDomainBestEffort(tabId);
         this.attachedTabs.add(tabId);
+        this.attachmentIds.set(tabId, crypto.randomUUID());
         await this.enableFrameDiscovery({ tabId }).catch((err) => {
           console.debug("[bsk cdp] frame discovery unavailable", { tabId, err });
         });
@@ -444,6 +451,7 @@ export class ChromiumCdp {
     this.attachInFlight.delete(tabId);
     if (!this.attachedTabs.has(tabId)) return;
     this.attachedTabs.delete(tabId);
+    this.attachmentIds.delete(tabId);
     this.clearDialogState(tabId);
     this.clearConsoleState(tabId);
     this.clearNetworkState(tabId);
@@ -502,6 +510,7 @@ export class ChromiumCdp {
     this.attachInFlight.clear();
     this.tabOwners.clear();
     this.attachedTabs.clear();
+    this.attachmentIds.clear();
     this.dialogBuffers.clear();
     this.dialogSequences.clear();
     this.consoleBuffers.clear();
@@ -848,6 +857,7 @@ export class ChromiumCdp {
     const listener = (source: chrome.debugger.Debuggee, _reason: string) => {
       if (typeof source.tabId === "number") {
         this.attachedTabs.delete(source.tabId);
+        this.attachmentIds.delete(source.tabId);
         this.attachInFlight.delete(source.tabId);
         this.tabOwners.delete(source.tabId);
         this.clearDialogState(source.tabId);

apps/extension/src/browser-driver/frame-graph.ts

@@ -8,6 +8,7 @@ export interface CdpFrame {
   parentFrameId?: string;
   ownerBackendNodeId?: number;
   url?: string;
+  loaderId?: string;
   target: CdpTarget;
 }
 
@@ -21,6 +22,7 @@ export interface CdpFrameTreeNode {
     id: string;
     parentId?: string;
     url?: string;
+    loaderId?: string;
   };
   childFrames?: CdpFrameTreeNode[];
 }
@@ -48,6 +50,7 @@ function mergeFrame(
     frameId: node.frame.id,
     ...(parentFrameId ? { parentFrameId } : {}),
     ...(url ? { url } : {}),
+    ...(node.frame.loaderId ? { loaderId: node.frame.loaderId } : {}),
     target,
   });
 }