fix(inquirerer): defer process.stdin/stdout access in defaultCLIOptions

packages/inquirerer/__tests__/no-eager-stdio.test.ts

@@ -0,0 +1,62 @@
+import { execFileSync } from 'child_process';
+import { mkdtempSync, writeFileSync } from 'fs';
+import { tmpdir } from 'os';
+import { join } from 'path';
+
+import { defaultCLIOptions } from '../src/commander';
+
+describe('inquirerer does not eagerly open stdio on require', () => {
+  it('exposes defaultCLIOptions.input/output as lazy getters', () => {
+    const inputDesc = Object.getOwnPropertyDescriptor(defaultCLIOptions, 'input');
+    const outputDesc = Object.getOwnPropertyDescriptor(defaultCLIOptions, 'output');
+
+    expect(inputDesc).toBeDefined();
+    expect(outputDesc).toBeDefined();
+    // Must be accessor properties, not data properties — otherwise
+    // `process.stdin` / `process.stdout` would be evaluated at
+    // module-load time and register libuv handles even for consumers
+    // that never construct a CLI.
+    expect(typeof inputDesc!.get).toBe('function');
+    expect(typeof outputDesc!.get).toBe('function');
+    expect(inputDesc!.value).toBeUndefined();
+    expect(outputDesc!.value).toBeUndefined();
+  });
+
+  it('reading the getters returns process.stdin / process.stdout', () => {
+    expect(defaultCLIOptions.input).toBe(process.stdin);
+    expect(defaultCLIOptions.output).toBe(process.stdout);
+  });
+
+  // End-to-end guard: spawn a fresh Node process with stdin piped (so fd 0
+  // is a PIPEWRAP, which is exactly the Jest-worker / spawned-child case
+  // that surfaced the original bug in pgsql-test → @pgpmjs/core → genomic
+  // → inquirerer). Require inquirerer, then assert the active handle set
+  // is empty — i.e. no stdio was lazily materialised just by importing.
+  it('require() alone does not materialise stdio handles', () => {
+    const dir = mkdtempSync(join(tmpdir(), 'inquirerer-stdio-'));
+    const probe = join(dir, 'probe.js');
+    writeFileSync(
+      probe,
+      `
+        require(${JSON.stringify(require.resolve('../dist/index.js'))});
+        setImmediate(() => {
+          const byType = {};
+          for (const h of process._getActiveHandles()) {
+            const t = (h && h.constructor && h.constructor.name) || typeof h;
+            byType[t] = (byType[t] || 0) + 1;
+          }
+          process.stdout.write(JSON.stringify(byType));
+        });
+      `
+    );
+
+    const out = execFileSync(process.execPath, [probe], {
+      input: '',
+      encoding: 'utf8',
+    });
+    const byType = JSON.parse(out);
+    // No Socket (stdin) or WriteStream (stdout) should be kept alive.
+    expect(byType.Socket).toBeUndefined();
+    expect(byType.WriteStream).toBeUndefined();
+  });
+});

packages/inquirerer/src/commander.ts

@@ -16,11 +16,21 @@ export interface CLIOptions {
   version: string;
 }
 
+// NOTE: `input` and `output` are lazy getters rather than plain properties.
+// `process.stdin` / `process.stdout` are Node getters that lazy-construct
+// streams on first access. When fd 0 is a pipe (e.g. a Jest worker or any
+// spawned child), constructing stdin registers a libuv PIPEWRAP handle
+// that the runtime must close before the process can exit. Evaluating
+// these defaults eagerly as object properties meant that merely
+// `require('inquirerer')` — even via a transitive dep that never
+// constructs `CLI` — would open stdin and produce a spurious open-handle
+// warning under `jest --detectOpenHandles`. Deferring the access to
+// read-time keeps the module side-effect free.
 export const defaultCLIOptions: CLIOptions = {
   version: `inquirerer@${getVersion()}`,
   noTty: false,
-  input: process.stdin,
-  output: process.stdout,
+  get input() { return process.stdin; },
+  get output() { return process.stdout; },
   minimistOpts: {
     alias: {
       v: 'version'