From 0fce6d3ee4f440abd1512924b776acd69181fbfe Mon Sep 17 00:00:00 2001
From: Florimond Manca <florimond.manca@gmail.com>
Date: Fri, 20 Nov 2020 12:47:26 +0100
Subject: [PATCH] Fix import of HTTP/1.1 connection causing thread-safety bug
 on 3.9 (#237)

* Fix import of HTTP/1.1 connection causing thread-safety bug on 3.9

* Typo
---
 httpcore/_async/connection.py |  3 +--
 httpcore/_sync/connection.py  |  3 +--
 tests/test_threadsafety.py    | 46 +++++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 4 deletions(-)
 create mode 100644 tests/test_threadsafety.py

diff --git a/httpcore/_async/connection.py b/httpcore/_async/connection.py
index d3d7b41b..530663d8 100644
--- a/httpcore/_async/connection.py
+++ b/httpcore/_async/connection.py
@@ -12,6 +12,7 @@
     NewConnectionRequired,
 )
 from .http import AsyncBaseHTTPConnection
+from .http11 import AsyncHTTP11Connection
 
 logger = get_logger(__name__)
 
@@ -150,8 +151,6 @@ def _create_connection(self, socket: AsyncSocketStream) -> None:
                 socket=socket, backend=self.backend, ssl_context=self.ssl_context
             )
         else:
-            from .http11 import AsyncHTTP11Connection
-
             self.is_http11 = True
             self.connection = AsyncHTTP11Connection(
                 socket=socket, ssl_context=self.ssl_context
diff --git a/httpcore/_sync/connection.py b/httpcore/_sync/connection.py
index f10f2aad..04042227 100644
--- a/httpcore/_sync/connection.py
+++ b/httpcore/_sync/connection.py
@@ -12,6 +12,7 @@
     NewConnectionRequired,
 )
 from .http import SyncBaseHTTPConnection
+from .http11 import SyncHTTP11Connection
 
 logger = get_logger(__name__)
 
@@ -150,8 +151,6 @@ def _create_connection(self, socket: SyncSocketStream) -> None:
                 socket=socket, backend=self.backend, ssl_context=self.ssl_context
             )
         else:
-            from .http11 import SyncHTTP11Connection
-
             self.is_http11 = True
             self.connection = SyncHTTP11Connection(
                 socket=socket, ssl_context=self.ssl_context
diff --git a/tests/test_threadsafety.py b/tests/test_threadsafety.py
new file mode 100644
index 00000000..81cdd95f
--- /dev/null
+++ b/tests/test_threadsafety.py
@@ -0,0 +1,46 @@
+import concurrent.futures
+
+import pytest
+
+import httpcore
+
+from .utils import Server
+
+
+def read_body(stream: httpcore.SyncByteStream) -> bytes:
+    try:
+        return b"".join(chunk for chunk in stream)
+    finally:
+        stream.close()
+
+
+@pytest.mark.parametrize(
+    "http2", [pytest.param(False, id="h11"), pytest.param(True, id="h2")]
+)
+def test_threadsafe_basic(server: Server, http2: bool) -> None:
+    """
+    The sync connection pool can be used to perform requests concurrently using
+    threads.
+
+    Also a regression test for: https://github.com/encode/httpx/issues/1393
+    """
+    with httpcore.SyncConnectionPool(http2=http2) as http:
+
+        def request(http: httpcore.SyncHTTPTransport) -> int:
+            method = b"GET"
+            url = (b"http", *server.netloc, b"/")
+            headers = [server.host_header]
+            status_code, headers, stream, ext = http.request(method, url, headers)
+            read_body(stream)
+            return status_code
+
+        with concurrent.futures.ThreadPoolExecutor(max_workers=4) as executor:
+            futures = [executor.submit(request, http) for _ in range(10)]
+            num_results = 0
+
+            for future in concurrent.futures.as_completed(futures):
+                status_code = future.result()
+                assert status_code == 200
+                num_results += 1
+
+            assert num_results == 10