http2: refactor error handling

This changes the error handling model of ServerHttp2Stream,
ServerHttp2Request and ServerHttp2Response.
An 'error' emitted on ServerHttp2Stream will not go to
'uncaughtException' anymore, but to the server 'streamError'.
On the stream 'error', ServerHttp2Request will emit 'abort', while
ServerHttp2Response would do nothing

See: #14963

doc/api/http2.md

@@ -1208,6 +1208,19 @@ added: v8.4.0
 
 * Extends: {net.Server}
 
+In `Http2Server`, there is no `'clientError'` event as there is in
+HTTP1. However, there are `'socketError'`, `'sessionError'`,  and
+`'streamError'`, for error happened on the socket, session or stream
+respectively.
+
+#### Event: 'socketError'
+<!-- YAML
+added: v8.4.0
+-->
+
+The `'socketError'` event is emitted when a `'socketError'` event is emitted by
+an `Http2Session` associated with the server.
+
 #### Event: 'sessionError'
 <!-- YAML
 added: v8.4.0
@@ -1217,13 +1230,15 @@ The `'sessionError'` event is emitted when an `'error'` event is emitted by
 an `Http2Session` object. If no listener is registered for this event, an
 `'error'` event is emitted.
 
-#### Event: 'socketError'
+#### Event: 'streamError'
 <!-- YAML
-added: v8.4.0
+added: REPLACEME
 -->
 
-The `'socketError'` event is emitted when a `'socketError'` event is emitted by
-an `Http2Session` associated with the server.
+* `socket` {http2.ServerHttp2Stream}
+
+If an `ServerHttp2Stream` emits an `'error'` event, it will be forwarded here.
+The stream will already be destroyed when this event is triggered.
 
 #### Event: 'stream'
 <!-- YAML

lib/http2.js

@@ -15,7 +15,7 @@ const {
   createSecureServer,
   connect,
   Http2ServerRequest,
-  Http2ServerResponse,
+  Http2ServerResponse
 } = require('internal/http2/core');
 
 module.exports = {
@@ -27,5 +27,5 @@ module.exports = {
   createSecureServer,
   connect,
   Http2ServerResponse,
-  Http2ServerRequest,
+  Http2ServerRequest
 };

lib/internal/http2/compat.js

@@ -58,8 +58,13 @@ function onStreamEnd() {
 }
 
 function onStreamError(error) {
-  const request = this[kRequest];
-  request.emit('error', error);
+  // this is purposefully left blank
+  //
+  // errors in compatibility mode are
+  // not forwarded to the request
+  // and response objects. However,
+  // they are forwarded to 'clientError'
+  // on the server by Http2Stream
 }
 
 function onRequestPause() {
@@ -82,11 +87,6 @@ function onStreamResponseDrain() {
   response.emit('drain');
 }
 
-function onStreamResponseError(error) {
-  const response = this[kResponse];
-  response.emit('error', error);
-}
-
 function onStreamClosedRequest() {
   const req = this[kRequest];
   req.push(null);
@@ -271,9 +271,7 @@ class Http2ServerResponse extends Stream {
     stream[kResponse] = this;
     this.writable = true;
     stream.on('drain', onStreamResponseDrain);
-    stream.on('error', onStreamResponseError);
     stream.on('close', onStreamClosedResponse);
-    stream.on('aborted', onAborted.bind(this));
     const onfinish = this[kFinish].bind(this);
     stream.on('streamClosed', onfinish);
     stream.on('finish', onfinish);

lib/internal/http2/core.js

@@ -1506,6 +1506,13 @@ class Http2Stream extends Duplex {
       this.once('ready', this._destroy.bind(this, err, callback));
       return;
     }
+
+    const server = session[kServer];
+
+    if (err && server) {
+      server.emit('streamError', err, this);
+    }
+
     process.nextTick(() => {
       debug(`[${sessionName(session[kType])}] destroying stream ${this[kID]}`);
 
@@ -1529,9 +1536,8 @@ class Http2Stream extends Duplex {
       // All done
       const rst = this[kState].rst;
       const code = rst ? this[kState].rstCode : NGHTTP2_NO_ERROR;
-      if (code !== NGHTTP2_NO_ERROR) {
-        const err = new errors.Error('ERR_HTTP2_STREAM_ERROR', code);
-        process.nextTick(() => this.emit('error', err));
+      if (!err && code !== NGHTTP2_NO_ERROR) {
+        err = new errors.Error('ERR_HTTP2_STREAM_ERROR', code);
       }
       process.nextTick(emit.bind(this, 'streamClosed', code));
       debug(`[${sessionName(session[kType])}] stream ${this[kID]} destroyed`);
@@ -1691,13 +1697,20 @@ function afterOpen(session, options, headers, getTrailers, err, fd) {
            doSendFileFD.bind(this, session, options, fd, headers, getTrailers));
 }
 
+function streamOnError(err) {
+  // we swallow the error for parity with HTTP1
+  // all the errors that ends here are not critical for the project
+  debug('ServerHttp2Stream errored, avoiding uncaughtException', err);
+}
+
 
 class ServerHttp2Stream extends Http2Stream {
   constructor(session, id, options, headers) {
     super(session, options);
     this[kInit](id);
     this[kProtocol] = headers[HTTP2_HEADER_SCHEME];
     this[kAuthority] = headers[HTTP2_HEADER_AUTHORITY];
+    this.on('error', streamOnError);
     debug(`[${sessionName(session[kType])}] created serverhttp2stream`);
   }
 
@@ -2556,6 +2569,8 @@ module.exports = {
   createServer,
   createSecureServer,
   connect,
+  Http2Session,
+  Http2Stream,
   Http2ServerRequest,
   Http2ServerResponse
 };

test/parallel/test-http2-client-stream-destroy-before-connect.js

@@ -36,18 +36,11 @@ server.on('listening', common.mustCall(() => {
   req.destroy(err);
 
   req.on('error', common.mustCall((err) => {
-    const fn = err.code === 'ERR_HTTP2_STREAM_ERROR' ?
-      common.expectsError({
-        code: 'ERR_HTTP2_STREAM_ERROR',
-        type: Error,
-        message: 'Stream closed with error code 2'
-      }) :
-      common.expectsError({
-        type: Error,
-        message: 'test'
-      });
-    fn(err);
-  }, 2));
+    common.expectsError({
+      type: Error,
+      message: 'test'
+    })(err);
+  }));
 
   req.on('streamClosed', common.mustCall((code) => {
     assert.strictEqual(req.rstCode, NGHTTP2_INTERNAL_ERROR);

test/parallel/test-http2-compat-errors.js

@@ -0,0 +1,52 @@
+// Flags: --expose-http2 --expose-internals
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const assert = require('assert');
+const h2 = require('http2');
+const { Http2Stream } = require('internal/http2/core');
+
+// Errors should not be reported both in Http2ServerRequest
+// and Http2ServerResponse
+
+let expected = null;
+
+const server = h2.createServer(common.mustCall(function(req, res) {
+  req.on('error', common.mustNotCall());
+  res.on('error', common.mustNotCall());
+  req.on('aborted', common.mustCall());
+  res.on('aborted', common.mustNotCall());
+
+  res.write('hello');
+
+  expected = new Error('kaboom');
+  res.stream.destroy(expected);
+  server.close();
+}));
+
+server.on('streamError', common.mustCall(function(err, stream) {
+  assert.strictEqual(err, expected);
+  assert.strictEqual(stream instanceof Http2Stream, true);
+}));
+
+server.listen(0, common.mustCall(function() {
+  const port = server.address().port;
+
+  const url = `http://localhost:${port}`;
+  const client = h2.connect(url, common.mustCall(function() {
+    const headers = {
+      ':path': '/foobar',
+      ':method': 'GET',
+      ':scheme': 'http',
+      ':authority': `localhost:${port}`,
+    };
+    const request = client.request(headers);
+    request.on('data', common.mustCall(function(chunk) {
+      // cause an error on the server side
+      client.destroy();
+    }));
+    request.end();
+  }));
+}));

test/parallel/test-http2-server-errors.js

@@ -0,0 +1,97 @@
+// Flags: --expose-http2 --expose-internals
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const assert = require('assert');
+const h2 = require('http2');
+const { Http2Stream } = require('internal/http2/core');
+
+// Errors should not be reported both in Http2ServerRequest
+// and Http2ServerResponse
+
+{
+  let expected = null;
+
+  const server = h2.createServer();
+
+  server.on('stream', common.mustCall(function(stream) {
+    stream.on('error', common.mustCall(function(err) {
+      assert.strictEqual(err, expected);
+    }));
+
+    stream.resume();
+    stream.write('hello');
+
+    expected = new Error('kaboom');
+    stream.destroy(expected);
+    server.close();
+  }));
+
+  server.on('streamError', common.mustCall(function(err, stream) {
+    assert.strictEqual(err, expected);
+    assert.strictEqual(stream instanceof Http2Stream, true);
+  }));
+
+  server.listen(0, common.mustCall(function() {
+    const port = server.address().port;
+
+    const url = `http://localhost:${port}`;
+    const client = h2.connect(url, common.mustCall(function() {
+      const headers = {
+        ':path': '/foobar',
+        ':method': 'GET',
+        ':scheme': 'http',
+        ':authority': `localhost:${port}`,
+      };
+      const request = client.request(headers);
+      request.on('data', common.mustCall(function(chunk) {
+        // cause an error on the server side
+        client.destroy();
+      }));
+      request.end();
+    }));
+  }));
+}
+
+{
+  let expected = null;
+
+  const server = h2.createServer();
+
+  server.on('stream', common.mustCall(function(stream) {
+    // there is no 'error'  handler, and this will not crash
+    stream.write('hello');
+    stream.resume();
+
+    expected = new Error('kaboom');
+    stream.destroy(expected);
+    server.close();
+  }));
+
+  server.on('streamError', common.mustCall(function(err, stream) {
+    assert.strictEqual(err, expected);
+    assert.strictEqual(stream instanceof Http2Stream, true);
+  }));
+
+  server.listen(0, common.mustCall(function() {
+    const port = server.address().port;
+
+    const url = `http://localhost:${port}`;
+    const client = h2.connect(url, common.mustCall(function() {
+      const headers = {
+        ':path': '/foobar',
+        ':method': 'GET',
+        ':scheme': 'http',
+        ':authority': `localhost:${port}`,
+      };
+      const request = client.request(headers);
+      request.on('data', common.mustCall(function(chunk) {
+        // cause an error on the server side
+        client.destroy();
+      }));
+      request.end();
+    }));
+  }));
+}