Added/Updated tests\bugs\gh_7257_misc_datatypes_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/gh_7257_misc_datatypes_test.py

@@ -7,11 +7,19 @@ TITLE:       Support for partial indices
 DESCRIPTION:
     Additional test to check misc datatypes in partial indices.
 NOTES:
+    [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").
+    
     Checked on 6.0.0.409, 5.0.1.1469
 """
 
 import pytest
 from firebird.qa import *
+from firebird.driver import DatabaseError
 from decimal import Decimal
 
 db = db_factory()
@@ -78,16 +86,32 @@ def run_ddl_dml(act, capsys, dtype, v_chk, v_max, use_rand = True):
                 con.commit()
 
         for x in [p for p in dml.split('^') if p.strip()]:
+            ps, rs = None, None
+            try:
                 ps = cur.prepare(x)
                 for s in ps.detailed_plan.split('\n'):
                     print( replace_leading(s) )
 
-            cur.execute(ps)
+                # ::: NB ::: 'ps' returns data, i.e. this is SELECTABLE expression.
+                # 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 = cur.execute(ps)
                 cur_cols = cur.description
-            for r in cur:
+                for r in rs:
                     for i in range(0,len(cur_cols)):
                         print( cur_cols[i][0], ':', r[i] )
                 con.commit()
+            except DatabaseError as e:
+                print(e.__str__())
+                print(e.gds_codes)
+            finally:
+                if rs:
+                    rs.close() # <<< EXPLICITLY CLOSING CURSOR RESULTS
+                if ps:
+                    ps.free()
 
         act.expected_stdout = f"""
             Select Expression