refactor: Address reviewer feedback — rename, simplify, remove tests

Per sentrivana's review:

Source changes:
- Rename ASYNC_TRANSPORT_ENABLED -> ASYNC_TRANSPORT_AVAILABLE
- Rename _is_async_transport -> _has_async_transport on _Client
- Use warnings.warn instead of logger.warning for close()/flush()
  with async transport
- Restore keep_alive guard in _get_httpcore_pool_options (the
  original Http2Transport behavior was intentional, but the reviewer
  wants it guarded)
- Add httpcore[asyncio] to tox.jinja for linters/mypy/common
- Revert tox.ini to origin/master (auto-generated, needs regen)
- Revert AGENTS.md lore section

Test removals (~1050 lines):
- Remove ALL test_async_worker_* tests (implementation details)
- Remove ALL test_make_transport_* tests (implementation details)
- Remove all test_handle_response_*, test_update_headers,
  test_prepare_envelope_* tests (implementation details or duplicates)
- Remove test_close_async_awaits_kill_task (duplicate)
- Remove test_handle_request_error_basic_coverage (too much mocking)
- Remove test_async_transport_event_loop_closed_scenario (mocking-heavy)
- Remove test_async_transport_get_header_value (no added benefit)
- Remove misc implementation-detail async transport tests
- Apply make_client() simplification suggestions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: BYK

scripts/populate_tox/tox.jinja

@@ -78,14 +78,17 @@ deps =
 
     linters: -r requirements-linting.txt
     linters: werkzeug<2.3.0
+    linters: httpcore[asyncio]
 
     mypy: -r requirements-linting.txt
     mypy: werkzeug<2.3.0
+    mypy: httpcore[asyncio]
     ruff: -r requirements-linting.txt
 
     # === Common ===
     py3.8-common: hypothesis
     common: pytest-asyncio
+    common: httpcore[asyncio]
     # See https://github.com/pytest-dev/pytest/issues/9621
     # and https://github.com/pytest-dev/pytest-forked/issues/67
     # for justification of the upper bound on pytest

sentry_sdk/client.py

@@ -1009,7 +1009,7 @@ def get_integration(
 
         return self.integrations.get(integration_name)
 
-    def _is_async_transport(self) -> bool:
+    def _has_async_transport(self) -> bool:
         """Check if the current transport is async."""
         return isinstance(self.transport, AsyncHttpTransport)
 
@@ -1045,11 +1045,10 @@ def close(
         semantics as :py:meth:`Client.flush`.
         """
         if self.transport is not None:
-            if self._is_async_transport():
-                logger.warning(
-                    "close() used with AsyncHttpTransport. "
-                    "Prefer close_async() for graceful async shutdown. "
-                    "Performing synchronous best-effort cleanup."
+            if self._has_async_transport():
+                warnings.warn(
+                    "close() used with AsyncHttpTransport. Use close_async() instead.",
+                    stacklevel=2,
                 )
                 self._flush_components()
             else:
@@ -1068,7 +1067,7 @@ async def close_async(
         semantics as :py:meth:`Client.flush_async`.
         """
         if self.transport is not None:
-            if not self._is_async_transport():
+            if not self._has_async_transport():
                 logger.debug(
                     "close_async() used with non-async transport, aborting. Please use close() instead."
                 )
@@ -1093,9 +1092,10 @@ def flush(
         :param callback: Is invoked with the number of pending events and the configured timeout.
         """
         if self.transport is not None:
-            if self._is_async_transport():
-                logger.warning(
-                    "flush() used with AsyncHttpTransport. Please use flush_async() instead."
+            if self._has_async_transport():
+                warnings.warn(
+                    "flush() used with AsyncHttpTransport. Use flush_async() instead.",
+                    stacklevel=2,
                 )
                 return
             if timeout is None:
@@ -1117,7 +1117,7 @@ async def flush_async(
         :param callback: Is invoked with the number of pending events and the configured timeout.
         """
         if self.transport is not None:
-            if not self._is_async_transport():
+            if not self._has_async_transport():
                 logger.debug(
                     "flush_async() used with non-async transport, aborting. Please use flush() instead."
                 )

sentry_sdk/transport.py

@@ -31,9 +31,9 @@
 try:
     import anyio  # noqa: F401
 
-    ASYNC_TRANSPORT_ENABLED = httpcore is not None
+    ASYNC_TRANSPORT_AVAILABLE = httpcore is not None
 except ImportError:
-    ASYNC_TRANSPORT_ENABLED = False
+    ASYNC_TRANSPORT_AVAILABLE = False
 
 import urllib3
 import certifi
@@ -545,18 +545,22 @@ def _get_httpcore_pool_options(
             "retries": 3,
         }
 
-        socket_options = (
-            self.options["socket_options"]
-            if self.options["socket_options"] is not None
-            else []
-        )
+        socket_options: "Optional[List[Tuple[int, int, int | bytes]]]" = None
+
+        if self.options["socket_options"] is not None:
+            socket_options = self.options["socket_options"]
 
-        used_options = {(o[0], o[1]) for o in socket_options}
-        for default_option in KEEP_ALIVE_SOCKET_OPTIONS:
-            if (default_option[0], default_option[1]) not in used_options:
-                socket_options.append(default_option)
+        if self.options["keep_alive"]:
+            if socket_options is None:
+                socket_options = []
 
-        options["socket_options"] = socket_options
+            used_options = {(o[0], o[1]) for o in socket_options}
+            for default_option in KEEP_ALIVE_SOCKET_OPTIONS:
+                if (default_option[0], default_option[1]) not in used_options:
+                    socket_options.append(default_option)
+
+        if socket_options is not None:
+            options["socket_options"] = socket_options
 
         ssl_context = ssl.create_default_context()
         ssl_context.load_verify_locations(
@@ -838,7 +842,7 @@ def _request(
 
 class AsyncHttpTransport(HttpTransportCore):
     def __init__(self: "Self", options: "Dict[str, Any]") -> None:
-        if not ASYNC_TRANSPORT_ENABLED:
+        if not ASYNC_TRANSPORT_AVAILABLE:
             raise RuntimeError(
                 "AsyncHttpTransport requires httpcore[asyncio]. "
                 "Install it with: pip install sentry-sdk[asyncio]"
@@ -1120,7 +1124,7 @@ def make_transport(options: "Dict[str, Any]") -> "Optional[Transport]":
         Http2Transport if use_http2_transport else HttpTransport
     )
 
-    if use_async_transport and ASYNC_TRANSPORT_ENABLED:
+    if use_async_transport and ASYNC_TRANSPORT_AVAILABLE:
         try:
             asyncio.get_running_loop()
             if async_integration:

tests/test_client.py

@@ -1833,23 +1833,6 @@ async def mock_wait_flush(timeout, callback=None):
     await client.close_async()
 
 
-@skip_under_gevent
-@pytest.mark.asyncio
-@pytest.mark.skipif(not PY38, reason="Async client methods require Python 3.8+")
-async def test_close_async_awaits_kill_task():
-    """Test close_async() awaits the kill task returned by transport.kill()."""
-    client = Client(
-        "https://foo@sentry.io/123",
-        _experiments={"transport_async": True},
-        integrations=[AsyncioIntegration()],
-    )
-    assert isinstance(client.transport, AsyncHttpTransport)
-
-    # close_async should call kill() and await the returned task
-    await client.close_async(timeout=1.0)
-    assert client.transport is None
-
-
 @skip_under_gevent
 @pytest.mark.asyncio
 @pytest.mark.skipif(not PY38, reason="Async client methods require Python 3.8+")