Guard C-API teardown during interpreter shutdown

Author: adsharma

src_py/_lbug_capi.py

@@ -995,8 +995,10 @@ def __init__(
         _check_state(state, "Failed to initialize database")
 
     def close(self) -> None:
+        lib = _LIB
         if self._database._database:
-            _LIB.lbug_database_destroy(ctypes.byref(self._database))
+            if lib is not None:
+                lib.lbug_database_destroy(ctypes.byref(self._database))
             self._database._database = None
 
     @staticmethod
@@ -1024,8 +1026,10 @@ def __init__(self, prepared: _LbugPreparedStatement):
         self._prepared = prepared
 
     def close(self) -> None:
+        lib = _LIB
         if self._prepared._prepared_statement:
-            _LIB.lbug_prepared_statement_destroy(ctypes.byref(self._prepared))
+            if lib is not None:
+                lib.lbug_prepared_statement_destroy(ctypes.byref(self._prepared))
             self._prepared._prepared_statement = None
 
     def is_success(self) -> bool:
@@ -1076,16 +1080,21 @@ def _adopt_blob(self, ptr: ctypes.POINTER(ctypes.c_uint8), length: int) -> bytes
         return bytes(ctypes.string_at(ptr, length))
 
     def close(self) -> None:
-        for ptr in self._owned_string_ptrs:
-            _LIB.lbug_destroy_string(ptr)
+        lib = _LIB
+
+        if lib is not None:
+            for ptr in self._owned_string_ptrs:
+                lib.lbug_destroy_string(ptr)
         self._owned_string_ptrs.clear()
 
-        for ptr in self._owned_blob_ptrs:
-            _LIB.lbug_destroy_blob(ptr)
+        if lib is not None:
+            for ptr in self._owned_blob_ptrs:
+                lib.lbug_destroy_blob(ptr)
         self._owned_blob_ptrs.clear()
 
         if self._result._query_result:
-            _LIB.lbug_query_result_destroy(ctypes.byref(self._result))
+            if lib is not None:
+                lib.lbug_query_result_destroy(ctypes.byref(self._result))
             self._result._query_result = None
 
     def __del__(self) -> None:
@@ -1764,8 +1773,10 @@ def __init__(self, database: Database, num_threads: int = 0):
             self.set_max_threads_for_exec(num_threads)
 
     def close(self) -> None:
+        lib = _LIB
         if self._connection._connection:
-            _LIB.lbug_connection_destroy(ctypes.byref(self._connection))
+            if lib is not None:
+                lib.lbug_connection_destroy(ctypes.byref(self._connection))
             self._connection._connection = None
 
     def set_max_threads_for_exec(self, num_threads: int) -> None:

test/test_capi_backend.py

@@ -3,6 +3,8 @@
 from datetime import date, datetime
 
 import ladybug as lb
+import ladybug._lbug_capi as lbug_capi
+import pytest
 
 
 def test_capi_backend_basic_query() -> None:
@@ -36,3 +38,15 @@ def test_capi_backend_parameter_binding() -> None:
 
     conn.close()
     db.close()
+
+
+def test_capi_close_tolerates_lib_teardown(monkeypatch: pytest.MonkeyPatch) -> None:
+    db = lb.Database(":memory:", backend="capi")
+    conn = lb.Connection(db)
+    result = conn.execute("RETURN 1 AS a;")
+
+    monkeypatch.setattr(lbug_capi, "_LIB", None)
+
+    result.close()
+    conn.close()
+    db.close()