Merge pull request #1540 from pikasTech/codex/1536-session-switch-projection

fix(workbench): gate session switch detail projection

web/hwlab-cloud-web/scripts/workbench-e2e-server.ts

@@ -247,6 +247,10 @@ function createScenarioState(scenarioId: string): ScenarioState {
     sessions.unshift(submitSplitSession());
     traces.trc_submit_split = submitSplitTrace();
   }
+  if (id === "session-switch-delayed-detail-frame") {
+    markSessionText(sessions, "ses_running", "SESSION_A_ONLY", "SESSION_A_ONLY running source session");
+    markSessionText(sessions, "ses_completed", "SESSION_B_ONLY", "SESSION_B_ONLY completed target session");
+  }
   if (id === "session-rail-many") {
     for (let index = 0; index < 46; index += 1) sessions.push(manyRailSession(index));
   }
@@ -285,7 +289,7 @@ function createScenarioState(scenarioId: string): ScenarioState {
     chatRequests: [],
     listOmitSelected: id === "selected-missing-from-list",
     sessionDelayMs: id === "loading" ? 2_500 : 0,
-    sessionDetailDelayMs: id === "legacy-cnv-deeplink-canonical" ? 1_500 : 0,
+    sessionDetailDelayMs: id === "legacy-cnv-deeplink-canonical" ? 1_500 : id === "session-switch-delayed-detail-frame" ? 900 : 0,
     chatDelayMs: id === "submit-authority-race" ? 1_000 : 0,
     terminalScript: id === "event-replay" || id === "running-to-terminal" || id === "stale-submit-restore",
     terminalFailureScript: id === "stale-submit-restore",
@@ -295,6 +299,17 @@ function createScenarioState(scenarioId: string): ScenarioState {
   };
 }
 
+function markSessionText(sessions: SessionRecord[], sessionId: string, userText: string, agentText: string): void {
+  const session = sessions.find((item) => item.sessionId === sessionId);
+  if (!session) return;
+  session.firstUserMessagePreview = userText;
+  session.messages = (session.messages ?? []).map((message) => {
+    if (message.role === "user") return { ...message, text: userText };
+    if (message.role === "agent") return { ...message, text: agentText };
+    return message;
+  });
+}
+
 function createManualSession(body: JsonRecord): SessionRecord {
   const now = new Date().toISOString();
   const token = state.scenarioId === "server-authoritative-create" ? "server_created" : Date.now().toString(36);

web/hwlab-cloud-web/src/stores/workbench.ts

@@ -75,14 +75,18 @@ export const useWorkbenchStore = defineStore("workbench", () => {
   async function hydrate(options: HydrateOptions = {}): Promise<void> {
     const routeRequestId = normalizeWorkbenchSessionRouteId(options.sessionId);
     const routeSessionId = normalizeWorkbenchSessionId(options.sessionId);
-    if (routeSessionId) setActiveSessionSelection(routeSessionId);
     const requestEpoch = beginSessionSelection();
     sessionsReady.value = sessions.value.length > 0;
     loading.value = true;
     error.value = null;
     const includeSessionId = routeSessionId ?? activeSessionId.value;
+    if (routeSessionId) {
+      sessionDetailLoadingId.value = routeSessionId;
+      setActiveSessionSelection(routeSessionId);
+    }
     const sessionsResult = await api.workbench.sessions({ includeSessionId });
     if (!sessionsResult.ok) {
+      clearSessionDetailLoading(includeSessionId);
       loading.value = false;
       error.value = sessionsResult.error ?? "session list unavailable";
       return;
@@ -93,9 +97,9 @@ export const useWorkbenchStore = defineStore("workbench", () => {
       setActiveSessionSelection(targetSessionId);
     }
     if (targetSessionId) sessionDetailLoadingId.value = targetSessionId;
+    const previousMessages = messages.value;
     const selected = targetSessionId ? await loadWorkbenchSession(targetSessionId, listedSessions.find((item) => item.sessionId === targetSessionId) ?? null) : null;
-    clearSessionDetailLoading(targetSessionId);
+    if (selected && !isArchivedSession(selected) && isCurrentSessionSelection(requestEpoch, selected.sessionId)) applySelectedSessionDetail(selected, previousMessages);
-    if (selected && !isArchivedSession(selected) && isCurrentSessionSelection(requestEpoch, selected.sessionId)) applySelectedSessionDetail(selected, messages.value);
     if (selected && !isArchivedSession(selected) && routeRequestId && !isCurrentSessionSelection(requestEpoch, selected.sessionId)) rememberSessionDetail(selected);
     if (selected && isArchivedSession(selected)) isolateSessionLoadFailure(selected.sessionId, null, [], "session archived", { restorePrevious: false });
     if (options.invalidRouteId || (targetSessionId && !selected)) isolateSessionLoadFailure(targetSessionId ?? options.invalidRouteId ?? "invalid-session", null, [], "session URL not found", { restorePrevious: false });
@@ -104,6 +108,7 @@ export const useWorkbenchStore = defineStore("workbench", () => {
     rememberSessionList(nextSessions);
     sessionsReady.value = true;
     void refreshSessionStatusAuthority(nextSessions);
+    clearSessionDetailLoading(targetSessionId);
     loading.value = false;
     await refreshProviderOptions();
     restartRealtime("hydrate");
@@ -156,27 +161,30 @@ export const useWorkbenchStore = defineStore("workbench", () => {
     const requestEpoch = beginSessionSelection();
     startWorkbenchSessionSwitch({ sessionId: normalized ?? requestId, source: existing ? "rail" : "deeplink", targetState: existing?.status ?? "unknown", cache: (existing?.messages?.length ?? 0) > 0 ? "warm" : "cold" });
     switchingSessionId.value = requestId;
-    if (normalized) setActiveSessionSelection(normalized);
     sessionDetailLoadingId.value = requestId;
+    loading.value = true;
+    if (normalized) setActiveSessionSelection(normalized);
     if (existing) {
       sessions.value = mergeSessionIntoList(sessions.value, existing);
       rememberSessionDetail(existing);
       sessionsReady.value = true;
     }
-    loading.value = true;
     const selected = await loadWorkbenchSession(requestId, existing);
-    loading.value = false;
-    clearSessionDetailLoading(requestId);
-    clearSwitchingSession(requestId);
     if (!isCurrentSessionRequest(requestEpoch, requestId, selected?.sessionId ?? normalized)) return true;
     if (selected && !isArchivedSession(selected)) {
       applySelectedSessionDetail(selected, previousMessages);
+      clearSessionDetailLoading(requestId);
+      clearSwitchingSession(requestId);
+      loading.value = false;
       error.value = null;
       await refreshSessions(selected.sessionId);
       finishWorkbenchSessionSwitchFullLoad(selected.sessionId, "ok");
       return activeSessionId.value === selected.sessionId;
     }
     isolateSessionLoadFailure(requestId, previousSessionId, previousMessages, isArchivedSession(selected) ? "session archived" : "session URL not found", { restorePrevious: Boolean(seed && normalized) });
+    clearSessionDetailLoading(requestId);
+    clearSwitchingSession(requestId);
+    loading.value = false;
     failWorkbenchSessionSwitch(normalized ?? requestId);
     return false;
   }

web/hwlab-cloud-web/tests/workbench-e2e/specs/session-switch-reload.spec.ts

@@ -1,6 +1,21 @@
 import { expect, fakeServerState, gotoWorkbench, saveScreenshot, test } from "../fixtures/test";
 import { selectors, sessionTab } from "../fixtures/selectors";
 
+type FrameSample = {
+  activeSessionId: string | null;
+  loading: boolean;
+  hasA: boolean;
+  hasB: boolean;
+  textPreview: string;
+};
+
+declare global {
+  interface Window {
+    __issue1536Sampling?: boolean;
+    __issue1536Samples?: FrameSample[];
+  }
+}
+
 test("session switch persists active session after reload", async ({ page }, testInfo) => {
   await gotoWorkbench(page);
   await expect(page.locator(sessionTab("ses_running"))).toHaveAttribute("data-active", "true");
@@ -20,6 +35,66 @@ test("session switch persists active session after reload", async ({ page }, tes
   await saveScreenshot(page, testInfo, "session-switch-reload");
 });
 
+test.describe("delayed session detail projection", () => {
+  test.use({ scenarioId: "session-switch-delayed-detail-frame" });
+
+  test("loading exit never flashes previous session messages under target session", async ({ page }, testInfo) => {
+    await gotoWorkbench(page, "/workbench/sessions/ses_running");
+    await expect(page.locator(sessionTab("ses_running"))).toHaveAttribute("data-active", "true");
+    await expect(page.locator(selectors.conversationList)).toContainText("SESSION_A_ONLY");
+    await saveScreenshot(page, testInfo, "session-switch-delayed-before");
+
+    await page.evaluate(() => {
+      const samples: FrameSample[] = [];
+      const read = (): void => {
+        const active = document.querySelector('.session-tab[data-active="true"]');
+        const panel = document.querySelector("#conversation-list");
+        const text = panel?.textContent ?? "";
+        samples.push({
+          activeSessionId: active?.getAttribute("data-session-id") ?? null,
+          loading: Boolean(document.querySelector("#conversation-list .conversation-detail-loading")),
+          hasA: text.includes("SESSION_A_ONLY"),
+          hasB: text.includes("SESSION_B_ONLY"),
+          textPreview: text.replace(/\s+/gu, " ").trim().slice(0, 160)
+        });
+      };
+      const loop = (): void => {
+        read();
+        if (window.__issue1536Sampling === true) requestAnimationFrame(loop);
+      };
+      window.__issue1536Samples = samples;
+      window.__issue1536Sampling = true;
+      requestAnimationFrame(loop);
+    });
+
+    await page.locator(sessionTab("ses_completed")).click();
+    await expect(page.locator(sessionTab("ses_completed"))).toHaveAttribute("data-active", "true");
+    await expect(page.locator("#conversation-list .conversation-detail-loading")).toBeVisible();
+    await saveScreenshot(page, testInfo, "session-switch-delayed-loading");
+
+    await expect(page.locator("#conversation-list .conversation-detail-loading")).toHaveCount(0);
+    await saveScreenshot(page, testInfo, "session-switch-delayed-first-non-loading");
+    await expect(page.locator(selectors.conversationList)).toContainText("SESSION_B_ONLY");
+    await saveScreenshot(page, testInfo, "session-switch-delayed-final");
+
+    const samples = await page.evaluate(() => {
+      window.__issue1536Sampling = false;
+      return window.__issue1536Samples ?? [];
+    }) as FrameSample[];
+    await testInfo.attach("session-switch-delayed-frame-samples.json", {
+      body: JSON.stringify(samples, null, 2),
+      contentType: "application/json"
+    });
+    const targetFrames = samples.filter((sample) => sample.activeSessionId === "ses_completed");
+    const leakedFrames = targetFrames.filter((sample) => sample.hasA);
+    const firstNonLoadingTarget = targetFrames.find((sample) => !sample.loading);
+
+    expect(leakedFrames, JSON.stringify(leakedFrames.slice(0, 5), null, 2)).toEqual([]);
+    expect(firstNonLoadingTarget?.hasB, JSON.stringify(firstNonLoadingTarget ?? null, null, 2)).toBe(true);
+    expect(samples.filter((sample) => sample.hasA && sample.hasB), "old and target messages must never share one frame").toEqual([]);
+  });
+});
+
 test.describe("empty session switch target", () => {
   test.use({ scenarioId: "session-switch-empty-reload" });