fix(qa): cancel Docker health probe bodies

src/plugin-sdk/qa-runtime.test.ts

@@ -1,8 +1,8 @@
+import { createServer } from "node:net";
 /**
  * Tests QA runtime command loading and private CLI gating.
  */
 import { Command } from "commander";
-import { createServer } from "node:net";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import {
   cleanupTempDirs,
@@ -60,6 +60,21 @@ describe("plugin-sdk qa-runtime", () => {
     };
   }
 
+  function cancelTrackedFetchResponse(ok = true) {
+    let canceled = false;
+    return {
+      response: {
+        ok,
+        body: {
+          cancel: vi.fn(async () => {
+            canceled = true;
+          }),
+        },
+      },
+      wasCanceled: () => canceled,
+    };
+  }
+
   it("stays cold until the runtime seam is used", async () => {
     const module = await import("./qa-runtime.js");
 
@@ -341,6 +356,52 @@ describe("plugin-sdk qa-runtime", () => {
     expect(fetchImpl).toHaveBeenCalledWith("http://172.18.0.4:18789/healthz");
   });
 
+  it("cancels compose service health probe response bodies", async () => {
+    const module = await import("./qa-runtime.js");
+    const runtime = module.createQaDockerRuntime({ auditContext: "qa-test" });
+    const runCommand = vi.fn(async (_command: string, args: string[]) => {
+      if (args.includes("ps")) {
+        return { stdout: "qa-gateway-one\n", stderr: "" };
+      }
+      return { stdout: "172.18.0.4\n", stderr: "" };
+    });
+    const probe = cancelTrackedFetchResponse(true);
+    const fetchImpl = vi.fn(async () => probe.response);
+
+    await expect(
+      runtime.resolveComposeServiceUrl(
+        "gateway",
+        18789,
+        "/tmp/docker-compose.yml",
+        "/repo",
+        runCommand,
+        fetchImpl,
+      ),
+    ).resolves.toBe("http://172.18.0.4:18789/");
+    expect(probe.wasCanceled()).toBe(true);
+  });
+
+  it("cancels waitForHealth response bodies after each probe", async () => {
+    const module = await import("./qa-runtime.js");
+    const runtime = module.createQaDockerRuntime({ auditContext: "qa-test" });
+    const first = cancelTrackedFetchResponse(false);
+    const second = cancelTrackedFetchResponse(true);
+    const responses = [first.response, second.response];
+    const fetchImpl = vi.fn(async () => responses.shift() ?? second.response);
+    const sleepImpl = vi.fn(async () => {});
+
+    await runtime.waitForHealth("http://127.0.0.1:18789/healthz", {
+      fetchImpl,
+      sleepImpl,
+      timeoutMs: 1000,
+      pollMs: 1,
+    });
+
+    expect(fetchImpl).toHaveBeenCalledTimes(2);
+    expect(first.wasCanceled()).toBe(true);
+    expect(second.wasCanceled()).toBe(true);
+  });
+
   it("resolves an unpinned QA Docker host port away from an occupied loopback default", async () => {
     const module = await import("./qa-runtime.js");
     const reservation = await occupyLoopbackPort();

src/plugin-sdk/qa-runtime.ts

@@ -249,7 +249,11 @@ export type QaDockerRunCommand = (
 ) => Promise<{ stdout: string; stderr: string }>;
 
 /** Minimal fetch-like health probe used by QA Docker runtime helpers. */
-export type QaDockerFetchLike = (input: string) => Promise<{ ok: boolean }>;
+export type QaDockerFetchResponse = {
+  ok: boolean;
+  body?: { cancel?: () => unknown } | null;
+};
+export type QaDockerFetchLike = (input: string) => Promise<QaDockerFetchResponse>;
 
 const DEFAULT_QA_DOCKER_COMMAND_TIMEOUT_MS = 120_000;
 
@@ -484,14 +488,23 @@ function parseDockerComposePsRows(stdout: string) {
 }
 
 async function isQaDockerHealthy(url: string, fetchImpl: QaDockerFetchLike) {
+  let response: QaDockerFetchResponse | undefined;
   try {
-    const response = await fetchImpl(url);
+    response = await fetchImpl(url);
     return response.ok;
   } catch {
     return false;
+  } finally {
+    await releaseQaDockerFetchResponse(response);
   }
 }
 
+async function releaseQaDockerFetchResponse(response: QaDockerFetchResponse | undefined) {
+  try {
+    await response?.body?.cancel?.();
+  } catch {}
+}
+
 /** Create Docker command, health-check, and compose helpers for QA harnesses. */
 export function createQaDockerRuntime(params: {
   auditContext: string;
@@ -548,14 +561,17 @@ export function createQaDockerRuntime(params: {
     let lastError: unknown = null;
 
     while (Date.now() < deadline) {
+      let response: QaDockerFetchResponse | undefined;
       try {
-        const response = await deps.fetchImpl(url);
+        response = await deps.fetchImpl(url);
         if (response.ok) {
           return;
         }
         lastError = new Error(`Health check returned non-OK for ${url}`);
       } catch (error) {
         lastError = error;
+      } finally {
+        await releaseQaDockerFetchResponse(response);
       }
       await deps.sleepImpl(pollMs);
     }