fix(prompt-gate): harden sync and team prompt dispatch

src/features/background-agent/session-route.test.ts

@@ -0,0 +1,74 @@
+import { afterEach, describe, expect, mock, test } from "bun:test"
+
+import { releaseAllPromptAsyncReservationsForTesting } from "../../shared/prompt-async-gate"
+import { unsafeTestValue } from "../../../test-support/unsafe-test-value"
+import { promptAsyncInDirectory, promptWithRetryInDirectory } from "./session-route"
+
+describe("background-agent session routing", () => {
+  afterEach(() => {
+    releaseAllPromptAsyncReservationsForTesting()
+  })
+
+  test("#given a routed prompt just dispatched #when the same child session is prompted again immediately #then promptAsync routing defers instead of enqueueing", async () => {
+    // given
+    const promptAsync = mock(async () => ({ data: "sent" }))
+    const client = {
+      session: {
+        promptAsync,
+      },
+    }
+    const args = {
+      path: { id: "ses_background_route_hold" },
+      body: { parts: [{ type: "text", text: "continue" }] },
+    }
+
+    // when
+    const first = await promptAsyncInDirectory(
+      unsafeTestValue(client),
+      unsafeTestValue(args),
+      "/workspace/project",
+    )
+    const second = promptAsyncInDirectory(
+      unsafeTestValue(client),
+      unsafeTestValue(args),
+      "/workspace/project",
+    )
+
+    // then
+    expect(first).toEqual({ data: "sent" })
+    await expect(second).rejects.toThrow("promptAsync skipped by gate: reserved")
+    expect(promptAsync).toHaveBeenCalledTimes(1)
+    expect(promptAsync.mock.calls[0]?.[0].query).toEqual({ directory: "/workspace/project" })
+  })
+
+  test("#given a background retry prompt just dispatched #when the same child session is prompted again immediately #then retry routing defers instead of enqueueing", async () => {
+    // given
+    const promptAsync = mock(async () => undefined)
+    const client = {
+      session: {
+        promptAsync,
+      },
+    }
+    const args = {
+      path: { id: "ses_background_retry_route_hold" },
+      body: { parts: [{ type: "text", text: "continue" }] },
+    }
+
+    // when
+    await promptWithRetryInDirectory(
+      unsafeTestValue(client),
+      unsafeTestValue(args),
+      "/workspace/project",
+    )
+    const second = promptWithRetryInDirectory(
+      unsafeTestValue(client),
+      unsafeTestValue(args),
+      "/workspace/project",
+    )
+
+    // then
+    await expect(second).rejects.toThrow("promptAsync skipped by gate: reserved")
+    expect(promptAsync).toHaveBeenCalledTimes(1)
+    expect(promptAsync.mock.calls[0]?.[0].query).toEqual({ directory: "/workspace/project" })
+  })
+})