Add id(self) suffix to closed-handle InterfaceError messages

Closed-handle errors on Connection / AsyncConnection / Cursor /
AsyncCursor previously read just "Connection is closed" / "Cursor is
closed" — operators tailing logs from a multi-connection / multi-
cursor application could not tell which instance was the offender
from a single traceback. Add an `(id={id(self)})` suffix that the SA
dialect's is_disconnect substring classifier (base.py:1268) treats
as inert (the "connection is closed" / "cursor is closed" substring
remains intact at the start of the message).

The classifier-pin test in sqlalchemy-dqlite verifies the new shape
still routes through is_disconnect; this commit ships the dbapi-side
sweep.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqlitedbapi/aio/connection.py

@@ -278,7 +278,7 @@ def _ensure_locks(self) -> tuple[asyncio.Lock, asyncio.Lock]:
         # without re-nulling them, leaking three asyncio primitives
         # per race. Fail fast here so no primitives are created.
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         # Fork-after-init: asyncio primitives are bound to the parent
         # loop and the inherited socket is shared. Reject up front
         # with the same diagnostic the sync sibling and the client
@@ -321,7 +321,7 @@ def _check_loop_binding(self) -> None:
         to a different loop. No-op when not yet bound.
         """
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         if _client_conn_mod._current_pid != self._creator_pid:
             raise InterfaceError(
                 "Connection used after fork; reconstruct from configuration in the target process."
@@ -355,7 +355,7 @@ def _check_loop_only(self) -> None:
     async def _ensure_connection(self) -> DqliteConnection:
         """Ensure the underlying connection is established."""
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
 
         if self._async_conn is not None:
             return self._async_conn
@@ -384,7 +384,7 @@ async def _ensure_connection(self) -> DqliteConnection:
             if self._closed:
                 with contextlib.suppress(Exception):
                     await built.close()
-                raise InterfaceError("Connection is closed")
+                raise InterfaceError(f"Connection is closed (id={id(self)})")
             self._async_conn = built
             # Flip the finalizer's "anything to clean up" gate. From
             # this point GC without close emits the ResourceWarning;
@@ -858,7 +858,7 @@ async def commit(self) -> None:
         # so the contract holds regardless of which branch we take.
         del self.messages[:]
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         if self._async_conn is None:
             return
         _, op_lock = self._ensure_locks()
@@ -868,7 +868,7 @@ async def commit(self) -> None:
             # released. Without this second check we would dereference
             # ``self._async_conn.execute`` on ``None``.
             if self._closed or self._async_conn is None:
-                raise InterfaceError("Connection is closed")
+                raise InterfaceError(f"Connection is closed (id={id(self)})")
             # Clear ``messages`` under the lock so the PEP 249
             # contract "messages cleared by every method call" is
             # atomic with the operation. Clearing only pre-lock leaves
@@ -903,14 +903,14 @@ async def rollback(self) -> None:
         # PEP 249 §6.1.1 messages-clear contract; see commit() above.
         del self.messages[:]
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         if self._async_conn is None:
             return
         _, op_lock = self._ensure_locks()
         async with op_lock:
             # Re-check under the lock for the same race as commit().
             if self._closed or self._async_conn is None:
-                raise InterfaceError("Connection is closed")
+                raise InterfaceError(f"Connection is closed (id={id(self)})")
             # Clear ``messages`` under the lock; see ``commit`` rationale.
             del self.messages[:]
             # Read ``in_transaction`` under the lock; see commit() for
@@ -938,7 +938,7 @@ def cursor(self) -> AsyncCursor:
         """
         del self.messages[:]
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         if self._loop_ref is not None:
             try:
                 current_loop = asyncio.get_running_loop()

src/dqlitedbapi/aio/cursor.py

@@ -165,7 +165,7 @@ def closed(self) -> bool:
 
     def _check_closed(self) -> None:
         if self._closed:
-            raise InterfaceError("Cursor is closed")
+            raise InterfaceError(f"Cursor is closed (id={id(self)})")
 
     def _reset_execute_state(self) -> None:
         """Clear per-execute state to the "no result set" baseline.

src/dqlitedbapi/connection.py

@@ -906,7 +906,7 @@ def _run_sync[T](self, coro: Coroutine[Any, Any, T]) -> T:
     async def _get_async_connection(self) -> DqliteConnection:
         """Get or create the underlying async connection."""
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
 
         if self._async_conn is not None:
             return self._async_conn
@@ -950,7 +950,7 @@ def connect(self) -> None:
         del self.messages[:]
         self._check_thread()
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         # _get_async_connection is a coroutine; route through _run_sync
         # so we share the same loop-in-thread the cursor path uses.
         self._run_sync(self._get_async_connection())
@@ -1295,7 +1295,7 @@ def commit(self) -> None:
         del self.messages[:]
         self._check_thread()
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         if self._async_conn is None:
             return
         # Local short-circuit when no transaction is active. Mirrors
@@ -1315,7 +1315,7 @@ def commit(self) -> None:
     async def _commit_async(self) -> None:
         """Async implementation of commit."""
         if self._async_conn is None:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         # Clear ``messages`` under the lock so the PEP 249 contract
         # "messages cleared by every method call" is atomic with the
         # operation. ``_run_sync`` holds ``_op_lock`` across this
@@ -1346,7 +1346,7 @@ def rollback(self) -> None:
         del self.messages[:]
         self._check_thread()
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         if self._async_conn is None:
             return
         # See commit() — same local short-circuit applies. Saves a
@@ -1358,7 +1358,7 @@ def rollback(self) -> None:
     async def _rollback_async(self) -> None:
         """Async implementation of rollback."""
         if self._async_conn is None:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         # In-lock messages clear; see ``_commit_async`` for the
         # rationale.
         del self.messages[:]
@@ -1376,7 +1376,7 @@ def cursor(self) -> Cursor:
         del self.messages[:]
         self._check_thread()
         if self._closed:
-            raise InterfaceError("Connection is closed")
+            raise InterfaceError(f"Connection is closed (id={id(self)})")
         cur = Cursor(self)
         self._cursors.add(cur)
         return cur

src/dqlitedbapi/cursor.py

@@ -900,7 +900,7 @@ def closed(self) -> bool:
 
     def _check_closed(self) -> None:
         if self._closed:
-            raise InterfaceError("Cursor is closed")
+            raise InterfaceError(f"Cursor is closed (id={id(self)})")
 
     def _reset_execute_state(self) -> None:
         """Clear per-execute state to the "no result set" baseline.