PYTHON-5011 Fix behavior of TLS connection errors on PyPy

pymongo/network_layer.py

@@ -28,7 +28,7 @@
     Union,
 )
 
-from pymongo import ssl_support
+from pymongo import _csot, ssl_support
 from pymongo._asyncio_task import create_task
 from pymongo.errors import _OperationCancelled
 from pymongo.socket_checker import _errno_from_exception
@@ -316,6 +316,42 @@ async def _async_receive(conn: socket.socket, length: int, loop: AbstractEventLo
     return mv
 
 
+_PYPY = "PyPy" in sys.version
+
+
+def wait_for_read(conn: Connection, deadline: Optional[float]) -> None:
+    """Block until at least one byte is read, or a timeout, or a cancel."""
+    sock = conn.conn
+    timed_out = False
+    # Check if the connection's socket has been manually closed
+    if sock.fileno() == -1:
+        return
+    while True:
+        # SSLSocket can have buffered data which won't be caught by select.
+        if hasattr(sock, "pending") and sock.pending() > 0:
+            readable = True
+        else:
+            # Wait up to 500ms for the socket to become readable and then
+            # check for cancellation.
+            if deadline:
+                remaining = deadline - time.monotonic()
+                # When the timeout has expired perform one final check to
+                # see if the socket is readable. This helps avoid spurious
+                # timeouts on AWS Lambda and other FaaS environments.
+                if remaining <= 0:
+                    timed_out = True
+                timeout = max(min(remaining, _POLL_TIMEOUT), 0)
+            else:
+                timeout = _POLL_TIMEOUT
+            readable = conn.socket_checker.select(sock, read=True, timeout=timeout)
+        if conn.cancel_context.cancelled:
+            raise _OperationCancelled("operation cancelled")
+        if readable:
+            return
+        if timed_out:
+            raise socket.timeout("timed out")
+
+
 def receive_data(conn: Connection, length: int, deadline: Optional[float]) -> memoryview:
     buf = bytearray(length)
     mv = memoryview(buf)
@@ -324,18 +360,25 @@ def receive_data(conn: Connection, length: int, deadline: Optional[float]) -> me
     # check for the cancellation signal after each timeout. Alternatively we
     # could close the socket but that does not reliably cancel recv() calls
     # on all OSes.
+    # When the timeout has expired we perform one final non-blocking recv.
+    # This helps avoid spurious timeouts when the response is actually already
+    # buffered on the client.
     orig_timeout = conn.conn.gettimeout()
     try:
         while bytes_read < length:
-            if deadline is not None:
-                # CSOT: Update timeout. When the timeout has expired perform one
-                # final non-blocking recv. This helps avoid spurious timeouts when
-                # the response is actually already buffered on the client.
-                short_timeout = min(max(deadline - time.monotonic(), 0), _POLL_TIMEOUT)
-            else:
-                short_timeout = _POLL_TIMEOUT
-            conn.set_conn_timeout(short_timeout)
             try:
+                # Use the legacy wait_for_read cancellation approach on PyPy due to PYTHON-5011.
+                if _PYPY:
+                    wait_for_read(conn, deadline)
+                    if _csot.get_timeout() and deadline is not None:
+                        conn.set_conn_timeout(max(deadline - time.monotonic(), 0))
+                else:
+                    if deadline is not None:
+                        short_timeout = min(max(deadline - time.monotonic(), 0), _POLL_TIMEOUT)
+                    else:
+                        short_timeout = _POLL_TIMEOUT
+                    conn.set_conn_timeout(short_timeout)
+
                 chunk_length = conn.conn.recv_into(mv[bytes_read:])
             except BLOCKING_IO_ERRORS:
                 if conn.cancel_context.cancelled:
@@ -345,6 +388,9 @@ def receive_data(conn: Connection, length: int, deadline: Optional[float]) -> me
             except socket.timeout:
                 if conn.cancel_context.cancelled:
                     raise _OperationCancelled("operation cancelled") from None
+                if _PYPY:
+                    # We reached the true deadline.
+                    raise
                 continue
             except OSError as exc:
                 if conn.cancel_context.cancelled: