WIP: Bisect to debug get-port error

Author: pimterry

.github/workflows/ci.yml

@@ -1,6 +1,45 @@
 name: CI
 on: [push, pull_request]
 jobs:
+  # Temporary: bisect which port-finding mode causes flaky abort test
+  bisect-port-finding:
+    name: "Bisect: ${{ matrix.port-mode }}"
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        port-mode: [simple, multi-host, get-port, get-port-preloaded]
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-node@v6
+        with:
+          node-version: '22.x'
+          check-latest: true
+          cache: 'npm'
+          cache-dependency-path: 'package.json'
+
+      - run: npm install
+      - run: npm run build
+
+      # Run the node tests 3 times to catch flakes
+      - name: "Run 1"
+        run: npm run test:node
+        env:
+          PORT_FIND_MODE: ${{ matrix.port-mode }}
+          NODE_OPTIONS: '--no-experimental-strip-types'
+      - name: "Run 2"
+        run: npm run test:node
+        env:
+          PORT_FIND_MODE: ${{ matrix.port-mode }}
+          NODE_OPTIONS: '--no-experimental-strip-types'
+      - name: "Run 3"
+        run: npm run test:node
+        env:
+          PORT_FIND_MODE: ${{ matrix.port-mode }}
+          NODE_OPTIONS: '--no-experimental-strip-types'
+
   build:
     name: Build & test
     runs-on: ubuntu-latest

package.json

@@ -66,6 +66,7 @@
     "postbuild:doc": "touch ./typedoc/.nojekyll",
     "test": "npm run build && npm run test:node",
     "test:node": "NODE_EXTRA_CA_CERTS=./test/fixtures/test-ca.pem TS_NODE_FILES=true mocha -r ts-node/register 'test/**/*.spec.ts'",
+    "test:node:bisect": "npm run build && echo '=== simple ===' && PORT_FIND_MODE=simple npm run test:node && echo '=== multi-host ===' && PORT_FIND_MODE=multi-host npm run test:node && echo '=== get-port ===' && PORT_FIND_MODE=get-port npm run test:node && echo '=== get-port-preloaded ===' && PORT_FIND_MODE=get-port-preloaded npm run test:node",
     "test:browser": "npm run with-admin -- karma start",
     "test:browser:debug": "npm run with-admin -- karma start --single-run=false --browsers ChromeWithCert",
     "test:perf": "NODE_EXTRA_CA_CERTS=./test/fixtures/test-ca.pem TS_NODE_FILES=true mocha -r ts-node/register 'test/performance/*.perf.ts'",

src/server/mockttp-server.ts

@@ -2,6 +2,7 @@ import { Buffer } from 'buffer';
 import * as stream from 'stream';
 import * as fs from 'fs';
 import * as net from "net";
+import * as os from "os";
 import * as tls from "tls";
 import * as http from "http";
 import * as http2 from "http2";
@@ -103,19 +104,59 @@ import { SocksServerOptions } from "./socks-server";
 
 const serverPortCheckMutex = new Mutex();
 
+// Toggle this to test different port-finding strategies:
+// Toggle this to test different port-finding strategies:
+// - 'simple': single-host check (default, no deps)
+// - 'multi-host': check all local interfaces (like get-port does)
+// - 'get-port': use actual get-port package (dynamic import)
+// - 'get-port-preloaded': pre-import get-port at module load time (matches c59e07d)
+const PORT_FIND_MODE = (process.env.PORT_FIND_MODE || 'simple') as
+    'simple' | 'multi-host' | 'get-port' | 'get-port-preloaded';
+
+// Pre-load get-port at module load time (like the static import in c59e07d)
+const preloadedGetPort = PORT_FIND_MODE === 'get-port-preloaded'
+    ? require('get-port') as { default: Function, portNumbers: Function }
+    : null;
+
 async function findFreePort(startPort: number, endPort: number): Promise<number> {
+    if (PORT_FIND_MODE === 'get-port') {
+        const { default: getPort, portNumbers } = await import('get-port');
+        return getPort({ port: portNumbers(startPort, endPort) });
+    }
+
+    if (PORT_FIND_MODE === 'get-port-preloaded') {
+        return preloadedGetPort!.default({ port: preloadedGetPort!.portNumbers(startPort, endPort) });
+    }
+
+    const hosts: Array<string | undefined> = PORT_FIND_MODE === 'multi-host'
+        ? (() => {
+            const results: Array<string | undefined> = [undefined, '0.0.0.0'];
+            for (const iface of Object.values(os.networkInterfaces())) {
+                for (const config of iface!) results.push(config.address);
+            }
+            return results;
+        })()
+        : [undefined]; // 'simple' mode: just default host
+
     for (let port = startPort; port <= endPort; port++) {
         try {
-            await new Promise<void>((resolve, reject) => {
-                const server = net.createServer();
-                server.unref();
-                server.once('error', reject);
-                server.once('listening', () => server.close(() => resolve()));
-                server.listen(port);
-            });
+            for (const host of hosts) {
+                await new Promise<void>((resolve, reject) => {
+                    const server = net.createServer();
+                    server.unref();
+                    server.once('error', reject);
+                    server.once('listening', () => server.close(() => resolve()));
+                    if (host !== undefined) {
+                        server.listen(port, host);
+                    } else {
+                        server.listen(port);
+                    }
+                });
+            }
             return port;
         } catch (e: any) {
-            if (e.code !== 'EADDRINUSE' && e.code !== 'EACCES') throw e;
+            if (e.code !== 'EADDRINUSE' && e.code !== 'EACCES' &&
+                e.code !== 'EADDRNOTAVAIL' && e.code !== 'EINVAL') throw e;
         }
     }
     throw new Error(`No open ports between ${startPort} and ${endPort}`);

test/integration/subscriptions/response-events.spec.ts

@@ -327,15 +327,6 @@ describe("Response subscriptions", () => {
 describe("Abort subscriptions", () => {
     let server = getLocal();
 
-    // DEBUG: Test whether get-port's presence causes flaky abort test
-    before(async function () {
-        this.timeout(30000);
-        const { default: getPort } = await import('get-port');
-        console.log('[DEBUG] Calling getPort() 50 times to simulate full suite usage...');
-        for (let i = 0; i < 50; i++) await getPort();
-        console.log('[DEBUG] Done. lockedPorts should now have 50 entries.');
-    });
-
     beforeEach(() => server.start());
     afterEach(() => server.stop());