events: add captureRejection option

PR-URL: https://github.com/nodejs/node/pull/27867
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

1 files changed, 297 insertions, 0 deletions

diff --git a/test/parallel/test-event-capture-rejections.js b/test/parallel/test-event-capture-rejections.js
new file mode 100644
index 0000000000..83da3184a6
--- /dev/null
+++ b/test/parallel/test-event-capture-rejections.js
@@ -0,0 +1,297 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const { EventEmitter, captureRejectionSymbol } = require('events');
+const { inherits } = require('util');
+
+// Inherits from EE without a call to the
+// parent constructor.
+function NoConstructor() {
+}
+
+inherits(NoConstructor, EventEmitter);
+
+function captureRejections() {
+  const ee = new EventEmitter({ captureRejections: true });
+  const _err = new Error('kaboom');
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err;
+  }));
+
+  ee.on('error', common.mustCall((err) => {
+    assert.strictEqual(err, _err);
+    process.nextTick(captureRejectionsTwoHandlers);
+  }));
+
+  ee.emit('something');
+}
+
+function captureRejectionsTwoHandlers() {
+  const ee = new EventEmitter({ captureRejections: true });
+  const _err = new Error('kaboom');
+
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err;
+  }));
+
+  // throw twice
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err;
+  }));
+
+  let count = 0;
+
+  ee.on('error', common.mustCall((err) => {
+    assert.strictEqual(err, _err);
+    if (++count === 2) {
+      process.nextTick(defaultValue);
+    }
+  }, 2));
+
+  ee.emit('something');
+}
+
+function defaultValue() {
+  const ee = new EventEmitter();
+  const _err = new Error('kaboom');
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err;
+  }));
+
+  process.removeAllListeners('unhandledRejection');
+
+  process.once('unhandledRejection', common.mustCall((err) => {
+    // restore default
+    process.on('unhandledRejection', (err) => { throw err; });
+
+    assert.strictEqual(err, _err);
+    process.nextTick(globalSetting);
+  }));
+
+  ee.emit('something');
+}
+
+function globalSetting() {
+  assert.strictEqual(EventEmitter.captureRejections, false);
+  EventEmitter.captureRejections = true;
+  const ee = new EventEmitter();
+  const _err = new Error('kaboom');
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err;
+  }));
+
+  ee.on('error', common.mustCall((err) => {
+    assert.strictEqual(err, _err);
+
+    // restore default
+    EventEmitter.captureRejections = false;
+    process.nextTick(configurable);
+  }));
+
+  ee.emit('something');
+}
+
+// We need to be able to configure this for streams, as we would
+// like to call destro(err) there.
+function configurable() {
+  const ee = new EventEmitter({ captureRejections: true });
+  const _err = new Error('kaboom');
+  ee.on('something', common.mustCall(async (...args) => {
+    assert.deepStrictEqual(args, [42, 'foobar']);
+    throw _err;
+  }));
+
+  assert.strictEqual(captureRejectionSymbol, Symbol.for('nodejs.rejection'));
+
+  ee[captureRejectionSymbol] = common.mustCall((err, type, ...args) => {
+    assert.strictEqual(err, _err);
+    assert.strictEqual(type, 'something');
+    assert.deepStrictEqual(args, [42, 'foobar']);
+    process.nextTick(globalSettingNoConstructor);
+  });
+
+  ee.emit('something', 42, 'foobar');
+}
+
+function globalSettingNoConstructor() {
+  assert.strictEqual(EventEmitter.captureRejections, false);
+  EventEmitter.captureRejections = true;
+  const ee = new NoConstructor();
+  const _err = new Error('kaboom');
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err;
+  }));
+
+  ee.on('error', common.mustCall((err) => {
+    assert.strictEqual(err, _err);
+
+    // restore default
+    EventEmitter.captureRejections = false;
+    process.nextTick(thenable);
+  }));
+
+  ee.emit('something');
+}
+
+function thenable() {
+  const ee = new EventEmitter({ captureRejections: true });
+  const _err = new Error('kaboom');
+  ee.on('something', common.mustCall((value) => {
+    const obj = {};
+
+    Object.defineProperty(obj, 'then', {
+      get: common.mustCall(() => {
+        return common.mustCall((resolved, rejected) => {
+          assert.strictEqual(resolved, undefined);
+          rejected(_err);
+        });
+      }, 1) // Only 1 call for Promises/A+ compat.
+    });
+
+    return obj;
+  }));
+
+  ee.on('error', common.mustCall((err) => {
+    assert.strictEqual(err, _err);
+    process.nextTick(avoidLoopOnRejection);
+  }));
+
+  ee.emit('something');
+}
+
+function avoidLoopOnRejection() {
+  const ee = new EventEmitter({ captureRejections: true });
+  const _err1 = new Error('kaboom');
+  const _err2 = new Error('kaboom2');
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err1;
+  }));
+
+  ee[captureRejectionSymbol] = common.mustCall(async (err) => {
+    assert.strictEqual(err, _err1);
+    throw _err2;
+  });
+
+  process.removeAllListeners('unhandledRejection');
+
+  process.once('unhandledRejection', common.mustCall((err) => {
+    // restore default
+    process.on('unhandledRejection', (err) => { throw err; });
+
+    assert.strictEqual(err, _err2);
+    process.nextTick(avoidLoopOnError);
+  }));
+
+  ee.emit('something');
+}
+
+function avoidLoopOnError() {
+  const ee = new EventEmitter({ captureRejections: true });
+  const _err1 = new Error('kaboom');
+  const _err2 = new Error('kaboom2');
+  ee.on('something', common.mustCall(async (value) => {
+    throw _err1;
+  }));
+
+  ee.on('error', common.mustCall(async (err) => {
+    assert.strictEqual(err, _err1);
+    throw _err2;
+  }));
+
+  process.removeAllListeners('unhandledRejection');
+
+  process.once('unhandledRejection', common.mustCall((err) => {
+    // restore default
+    process.on('unhandledRejection', (err) => { throw err; });
+
+    assert.strictEqual(err, _err2);
+    process.nextTick(thenableThatThrows);
+  }));
+
+  ee.emit('something');
+}
+
+function thenableThatThrows() {
+  const ee = new EventEmitter({ captureRejections: true });
+  const _err = new Error('kaboom');
+  ee.on('something', common.mustCall((value) => {
+    const obj = {};
+
+    Object.defineProperty(obj, 'then', {
+      get: common.mustCall(() => {
+        throw _err;
+      }, 1) // Only 1 call for Promises/A+ compat.
+    });
+
+    return obj;
+  }));
+
+  ee.on('error', common.mustCall((err) => {
+    assert.strictEqual(err, _err);
+    process.nextTick(resetCaptureOnThrowInError);
+  }));
+
+  ee.emit('something');
+}
+
+function resetCaptureOnThrowInError() {
+  const ee = new EventEmitter({ captureRejections: true });
+  ee.on('something', common.mustCall(async (value) => {
+    throw new Error('kaboom');
+  }));
+
+  ee.once('error', common.mustCall((err) => {
+    throw err;
+  }));
+
+  process.removeAllListeners('uncaughtException');
+
+  process.once('uncaughtException', common.mustCall((err) => {
+    process.nextTick(next);
+  }));
+
+  ee.emit('something');
+
+  function next() {
+    process.on('uncaughtException', common.mustNotCall());
+
+    const _err = new Error('kaboom2');
+    ee.on('something2', common.mustCall(async (value) => {
+      throw _err;
+    }));
+
+    ee.on('error', common.mustCall((err) => {
+      assert.strictEqual(err, _err);
+
+      process.removeAllListeners('uncaughtException');
+
+      // restore default
+      process.on('uncaughtException', (err) => { throw err; });
+
+      process.nextTick(argValidation);
+    }));
+
+    ee.emit('something2');
+  }
+}
+
+function argValidation() {
+
+  function testType(obj) {
+    common.expectsError(() => new EventEmitter({ captureRejections: obj }), {
+      code: 'ERR_INVALID_ARG_TYPE',
+      type: TypeError
+    });
+
+    common.expectsError(() => EventEmitter.captureRejections = obj, {
+      code: 'ERR_INVALID_ARG_TYPE',
+      type: TypeError
+    });
+  }
+
+  testType([]);
+  testType({ hello: 42 });
+  testType(42);
+}
+
+captureRejections();