⚡ Fix unintentional performance regression with multiple concurrent m…

…ultiplexed connection within a single Session (#86)

was due to an abusive lock.

HISTORY.md

@@ -1,6 +1,12 @@
 Release History
 ===============
 
+3.4.7 (2024-02-21)
+------------------
+
+**Fixed**
+- Unintentional performance regression with multiple concurrent multiplexed connection within a single Session.
+
 3.4.6 (2024-02-21)
 ------------------
 

docs/dev/migrate.rst

@@ -17,21 +17,21 @@ Developer migration
 Niquests aims to be as compatible as possible with Requests, and that is
 with confidence that you can migrate to Niquests without breaking changes.
 
-.. code-block::python
+.. code-block:: python
     import requests
 
     requests.get(...)
 
 Would turn into either
 
-.. code-block::python
+.. code-block:: python
     import niquests
 
     niquests.get(...)
 
 Or simply
 
-.. code-block::python
+.. code-block:: python
     import niquests as requests
 
     requests.get(...)
@@ -51,7 +51,7 @@ To overcome this, we will introduce you to a clever bypass. If you are using pyt
 following in your ``conftest.py``, see https://docs.pytest.org/en/6.2.x/fixture.html#conftest-py-sharing-fixtures-across-multiple-files
 for more information. (The goal would simply to execute the following piece of code before the tests)
 
-.. code-block::python
+.. code-block:: python
     from sys import modules
 
     import niquests

src/niquests/__version__.py

@@ -9,9 +9,9 @@
 __url__: str = "https://niquests.readthedocs.io"
 
 __version__: str
-__version__ = "3.4.6"
+__version__ = "3.4.7"
 
-__build__: int = 0x030406
+__build__: int = 0x030407
 __author__: str = "Kenneth Reitz"
 __author_email__: str = "me@kennethreitz.org"
 __license__: str = "Apache-2.0"

src/niquests/adapters.py

@@ -273,6 +273,7 @@ def __init__(
 
         #: we keep a list of pending (lazy) response
         self._promises: dict[str, Response] = {}
+        self._orphaned: list[BaseHTTPResponse] = []
         self._max_in_flight_multiplexed = (
             max_in_flight_multiplexed
             if max_in_flight_multiplexed is not None
@@ -731,9 +732,6 @@ def send(
         if isinstance(request.body, (list, dict)):
             raise ValueError("Body contains unprepared native list or dict.")
 
-        if multiplexed:
-            self._promise_lock.acquire()
-
         try:
             resp_or_promise = conn.urlopen(  # type: ignore[call-overload]
                 method=request.method,
@@ -796,9 +794,6 @@ def send(
 
         r = self.build_response(request, resp_or_promise)
 
-        if multiplexed:
-            self._promise_lock.release()
-
         if mutate_response_class:
             if not issubclass(mutate_response_class, Response):
                 raise TypeError(
@@ -1011,7 +1006,21 @@ def gather(self, *responses: Response, max_fetch: int | None = None) -> None:
                     if max_fetch is not None and max_fetch == 0:
                         return
 
-                    low_resp = self.poolmanager.get_response()
+                    low_resp = None
+
+                    if self._orphaned:
+                        for orphan in self._orphaned:
+                            try:
+                                if orphan._fp.from_promise.uid in self._promises:  # type: ignore[union-attr]
+                                    low_resp = orphan
+                                    break
+                            except AttributeError:
+                                continue
+                        if low_resp is not None:
+                            self._orphaned.remove(low_resp)
+
+                    if low_resp is None:
+                        low_resp = self.poolmanager.get_response()
 
                     if low_resp is None:
                         break
@@ -1031,7 +1040,8 @@ def gather(self, *responses: Response, max_fetch: int | None = None) -> None:
                         else None
                     )
 
-                    if response is None:  # todo: we should raise an exception instead!
+                    if response is None:
+                        self._orphaned.append(low_resp)
                         continue
 
                     self._future_handler(response, low_resp)