http: make OutgoingMessage more streamlike

Implement missing getters error & closed. Add support for
proper "writable" check through `isWritable` helper.

We cannot fix the `OutgoingMessage.writable` property as that
would break the ecosystem.

PR-URL: #45672
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: ronag

lib/_http_outgoing.js

@@ -88,6 +88,7 @@ const kCorked = Symbol('corked');
 const kUniqueHeaders = Symbol('kUniqueHeaders');
 const kBytesWritten = Symbol('kBytesWritten');
 const kEndCalled = Symbol('kEndCalled');
+const kErrored = Symbol('errored');
 
 const nop = () => {};
 
@@ -147,10 +148,26 @@ function OutgoingMessage() {
   this._keepAliveTimeout = 0;
 
   this._onPendingData = nop;
+
+  this[kErrored] = null;
 }
 ObjectSetPrototypeOf(OutgoingMessage.prototype, Stream.prototype);
 ObjectSetPrototypeOf(OutgoingMessage, Stream);
 
+ObjectDefineProperty(OutgoingMessage.prototype, 'errored', {
+  __proto__: null,
+  get() {
+    return this[kErrored];
+  },
+});
+
+ObjectDefineProperty(OutgoingMessage.prototype, 'closed', {
+  __proto__: null,
+  get() {
+    return this._closed;
+  },
+});
+
 ObjectDefineProperty(OutgoingMessage.prototype, 'writableFinished', {
   __proto__: null,
   get() {
@@ -320,6 +337,8 @@ OutgoingMessage.prototype.destroy = function destroy(error) {
   }
   this.destroyed = true;
 
+  this[kErrored] = error;
+
   if (this.socket) {
     this.socket.destroy(error);
   } else {

test/parallel/test-http-client-incomingmessage-destroy.js

@@ -20,6 +20,13 @@ server.listen(0, () => {
   get({
     port: server.address().port
   }, common.mustCall((res) => {
-    res.destroy(new Error('Destroy test'));
+    const err = new Error('Destroy test');
+    assert.strictEqual(res.errored, null);
+    res.destroy(err);
+    assert.strictEqual(res.closed, false);
+    assert.strictEqual(res.errored, err);
+    res.on('close', () => {
+      assert.strictEqual(res.closed, true);
+    });
   }));
 });

test/parallel/test-http-outgoing-destroyed.js

@@ -1,24 +1,55 @@
 'use strict';
 const common = require('../common');
 const http = require('http');
+const assert = require('assert');
 
-const server = http.createServer(common.mustCall((req, res) => {
-  req.pipe(res);
-  res.on('error', common.mustNotCall());
-  res.on('close', common.mustCall(() => {
-    res.end('asd');
-    process.nextTick(() => {
-      server.close();
-    });
-  }));
-})).listen(0, () => {
-  http
-    .request({
-      port: server.address().port,
-      method: 'PUT'
-    })
-    .on('response', (res) => {
-      res.destroy();
-    })
-    .write('asd');
-});
+{
+  const server = http.createServer(common.mustCall((req, res) => {
+    assert.strictEqual(res.closed, false);
+    req.pipe(res);
+    res.on('error', common.mustNotCall());
+    res.on('close', common.mustCall(() => {
+      assert.strictEqual(res.closed, true);
+      res.end('asd');
+      process.nextTick(() => {
+        server.close();
+      });
+    }));
+  })).listen(0, () => {
+    http
+      .request({
+        port: server.address().port,
+        method: 'PUT'
+      })
+      .on('response', (res) => {
+        res.destroy();
+      })
+      .write('asd');
+  });
+}
+
+{
+  const server = http.createServer(common.mustCall((req, res) => {
+    assert.strictEqual(res.closed, false);
+    req.pipe(res);
+    res.on('error', common.mustNotCall());
+    res.on('close', common.mustCall(() => {
+      assert.strictEqual(res.closed, true);
+      process.nextTick(() => {
+        server.close();
+      });
+    }));
+    const err = new Error('Destroy test');
+    res.destroy(err);
+    assert.strictEqual(res.errored, err);
+  })).listen(0, () => {
+    http
+      .request({
+        port: server.address().port,
+        method: 'PUT'
+      })
+      .on('error', common.mustCall())
+      .write('asd');
+  });
+
+}