From cfaba15c1f2dbf39891a7e3bacf59f8eafca1332 Mon Sep 17 00:00:00 2001
From: Maximilian Hils <git@maximilianhils.com>
Date: Fri, 19 Feb 2021 19:34:52 +0100
Subject: [PATCH] fix regression introduced in 70e08c880 (#4459)

---
 mitmproxy/proxy/layers/http/__init__.py       |  8 ++++---
 .../mitmproxy/proxy/layers/http/test_http2.py | 23 +++++++++++++++++++
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/mitmproxy/proxy/layers/http/__init__.py b/mitmproxy/proxy/layers/http/__init__.py
index 76b38e3e9..1705b8934 100644
--- a/mitmproxy/proxy/layers/http/__init__.py
+++ b/mitmproxy/proxy/layers/http/__init__.py
@@ -628,16 +628,18 @@ class HttpLayer(layer.Layer):
                 h2_to_h1 = self.context.client.alpn == b"h2" and not conn_is_pending_or_h2
                 connection_suitable = (
                     event.connection_spec_matches(connection)
-                    and connection.connected
                     and not h2_to_h1
                 )
                 if connection_suitable:
                     if connection in self.waiting_for_establishment:
                         self.waiting_for_establishment[connection].append(event)
-                    else:
+                        return
+                    elif connection.connected:
                         stream = self.command_sources.pop(event)
                         yield from self.event_to_child(stream, GetHttpConnectionCompleted(event, (connection, None)))
-                    return
+                        return
+                    else:
+                        pass  # the connection is at least half-closed already, we want a new one.
 
         can_use_context_connection = (
             self.context.server not in self.connections and
diff --git a/test/mitmproxy/proxy/layers/http/test_http2.py b/test/mitmproxy/proxy/layers/http/test_http2.py
index 52dedce98..6fe97bb9e 100644
--- a/test/mitmproxy/proxy/layers/http/test_http2.py
+++ b/test/mitmproxy/proxy/layers/http/test_http2.py
@@ -467,6 +467,29 @@ def test_max_concurrency(tctx):
     assert req2.stream_id == 3
 
 
+def test_stream_concurrent_get_connection(tctx):
+    """Test that an immediate second request for the same domain does not trigger a second connection attempt."""
+    playbook, cff = start_h2_client(tctx)
+    playbook.hooks = False
+
+    server = Placeholder(Server)
+    data = Placeholder(bytes)
+
+    assert (playbook
+            >> DataReceived(tctx.client, cff.build_headers_frame(example_request_headers, flags=["END_STREAM"], stream_id=1).serialize())
+            << (o := OpenConnection(server))
+            >> DataReceived(tctx.client, cff.build_headers_frame(example_request_headers, flags=["END_STREAM"], stream_id=3).serialize())
+            >> reply(None, to=o, side_effect=make_h2)
+            << SendData(server, data)
+            )
+    frames = decode_frames(data())
+    assert [type(x) for x in frames] == [
+        hyperframe.frame.SettingsFrame,
+        hyperframe.frame.HeadersFrame,
+        hyperframe.frame.HeadersFrame,
+    ]
+
+
 def test_kill_stream(tctx):
     """Test that we can kill individual streams."""
     playbook, cff = start_h2_client(tctx)