Added/Updated tests\bugs\core_6048_test.py: Resultset of cursor that executes using instance of selectable PreparedStatement must be stored in some variable in order to have ability close it EXPLICITLY, before PS will be freed. Otherwise access violation can raises when Python runs garbage collection.

tests/bugs/core_6048_test.py

@@ -33,6 +33,13 @@ NOTES:
 
     ::: NB-2 :::
     Careful tuning required on each tesing box for this test.
+
+    [18.01.2025] pzotov
+    Resultset of cursor that executes using instance of selectable PreparedStatement must be stored
+    in some variable in order to have ability close it EXPLICITLY (before PS will be freed).
+    Otherwise access violation raises during Python GC and pytest hangs at final point (does not return control to OS).
+    This occurs at least for: Python 3.11.2 / pytest: 7.4.4 / firebird.driver: 1.10.6 / Firebird.Qa: 0.19.3
+    The reason of that was explained by Vlad, 26.10.24 17:42 ("oddities when use instances of selective statements").
 """
 
 import os
@@ -125,6 +132,9 @@ def test_1(act: Action, capsys):
             print( e.__str__() )
 
         cur2 = con2.cursor()
+        ps, rs = None, None
+
+        try:
             ps = cur2.prepare('select mon$crypt_page, mon$crypt_state from mon$database')
 
             # This will store different number of pages which are currently encrypted.
@@ -140,8 +150,16 @@ def test_1(act: Action, capsys):
                     print(f'TIMEOUT EXPIRATION: encryption took {d1.seconds*1000 + d1.microseconds//1000} ms which exceeds limit = {MAX_WAITING_ENCR_FINISH} ms.')
                     break
 
-            cur2.execute(ps)
+                # ::: NB ::: 'ps' returns data, i.e. this is SELECTABLE expression.
-            crypt_page, crypt_state = cur2.fetchone()
+                # We have to store result of cur.execute(<psInstance>) in order to
+                # close it explicitly.
+                # Otherwise AV can occur during Python garbage collection and this
+                # causes pytest to hang on its final point.
+                # Explained by hvlad, email 26.10.24 17:42
+                rs = cur2.execute(ps)
+                for r in rs:
+                    crypt_page, crypt_state = r[:2]
+    
                 con2.commit()
 
                 # 0 = non crypted;
@@ -157,7 +175,16 @@ def test_1(act: Action, capsys):
                 elif len(encrypting_pages_set) > ENCRYPTING_PAGES_MIN_CNT:
                     break
                 else:
-                time.sleep(0.5)
+                    time.sleep(0.1)
+
+        except DatabaseError as e:
+            print( e.__str__() )
+            print(e.gds_codes)
+        finally:
+            if rs:
+                rs.close() # <<< EXPLICITLY CLOSING CURSOR RESULTS
+            if ps:
+                ps.free()
 
         # ---------------------------------------------------------