fix: cleanup wrongly marked coverage pragmas exercised by regression test

Author: RJ Lopez

src/mcp/client/session_group.py

@@ -146,7 +146,7 @@ def __init__(
         self._session_exit_stacks = {}
         self._component_name_hook = component_name_hook
 
-    async def __aenter__(self) -> Self:  # pragma: no cover
+    async def __aenter__(self) -> Self:
         # Enter the exit stack only if we created it ourselves
         if self._owns_exit_stack:
             await self._exit_stack.__aenter__()
@@ -157,7 +157,7 @@ async def __aexit__(
         _exc_type: type[BaseException] | None,
         _exc_val: BaseException | None,
         _exc_tb: TracebackType | None,
-    ) -> bool | None:  # pragma: no cover
+    ) -> bool | None:
         """Closes session exit stacks and main exit stack upon completion."""
 
         # Only close the main exit stack if we created it
@@ -323,7 +323,7 @@ async def _establish_session(
             await self._exit_stack.enter_async_context(session_stack)
 
             return result.server_info, session
-        except Exception:  # pragma: no cover
+        except Exception:
             # If anything during this setup fails, ensure the session-specific
             # stack is closed.
             await session_stack.aclose()

src/mcp/shared/session.py

@@ -451,7 +451,7 @@ async def _handle_session_message(message: SessionMessage) -> None:
                     try:
                         await stream.send(JSONRPCError(jsonrpc="2.0", id=id, error=error))
                         await stream.aclose()
-                    except Exception:  # pragma: no cover
+                    except Exception:
                         # Stream might already be closed
                         pass
                 self._response_streams.clear()

tests/client/test_session_group.py

@@ -5,8 +5,10 @@
 import sys
 from unittest import mock
 
-if sys.version_info < (3, 11):
-    from exceptiongroup import BaseExceptionGroup  # pragma: no cover # noqa: A004
+if sys.version_info < (3, 11):  # pragma: lax no cover
+    from exceptiongroup import BaseExceptionGroup
+else:  # pragma: lax no cover
+    BaseExceptionGroup = ExceptionGroup
 
 import httpx
 import pytest
@@ -418,10 +420,10 @@ def _walk(e: BaseException | None) -> bool:
             return False
         seen.add(id(e))
         if isinstance(e, RuntimeError) and "cancel scope" in str(e).lower():
-            return True  # pragma: no cover
+            return True
         if isinstance(e, BaseExceptionGroup):
-            if any(_walk(child) for child in e.exceptions):  # type: ignore # pragma: no cover
-                return True  # pragma: no cover
+            if any(_walk(child) for child in e.exceptions):  # type: ignore
+                return True
         return _walk(e.__cause__) or _walk(e.__context__)
 
     return _walk(exc)
@@ -447,7 +449,7 @@ async def test_unreachable_streamable_http_error_is_catchable() -> None:
             except BaseException as inner:
                 # Expected post-fix: real ConnectError lands here.
                 caught = inner
-    except BaseException as outer:  # pragma: no cover
+    except BaseException as outer:  # pragma: lax no cover
         # If we land here, the error escaped past the inner handler --
         # that is the regression case (masking RuntimeError surfacing
         # from __aexit__ instead of the real ConnectError propagating).