From 7740052e00420f98e03374c678645ff40cc33bde Mon Sep 17 00:00:00 2001
From: pavel-zotov <p519446@yandex.ru>
Date: Sat, 18 Jan 2025 16:08:16 +0300
Subject: [PATCH] Added/Updated tests\bugs\gh_7388_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_7388_test.py | 40 ++++++++++++++++++++++++++++++++------
 1 file changed, 34 insertions(+), 6 deletions(-)

diff --git a/tests/bugs/gh_7388_test.py b/tests/bugs/gh_7388_test.py
index 7fa40747..89735d7e 100644
--- a/tests/bugs/gh_7388_test.py
+++ b/tests/bugs/gh_7388_test.py
@@ -13,11 +13,20 @@ NOTES:
     [20.01.2024] pzotov
     Confirmed problem on 5.0.0.871.
     Checked on 6.0.0.218, 5.0.1.1318.
+
+    [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 pytest
 from pathlib import Path
+
+import pytest
 from firebird.qa import *
+from firebird.driver import DatabaseError
 
 init_sql = """
     create view v1
@@ -37,7 +46,7 @@ SUCCESS_MSG = "Expected: table statistics are identical."
 
 #----------------------------------------------------------
 
-def replace_leading(source, char="#"):
+def replace_leading(source, char="."):
     stripped = source.lstrip()
     return char * (len(source) - len(stripped)) + stripped
 
@@ -78,12 +87,21 @@ def test_1(act: Action, capsys):
         result_map = {}
 
         for qry_txt in q_map.keys():
-            with cur.prepare(qry_txt) as ps:
+            ps, rs = None, None
+            try:
+                ps = cur.prepare(qry_txt)
                 q_map[qry_txt] = ps.detailed_plan
                 for tab_nm,tab_id in t_map.items():
                     tabstat1 = [ p for p in con.info.get_table_access_stats() if p.table_id == tab_id ]
-                    cur.execute(qry_txt)
-                    for r in cur:
+
+                    # ::: 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)
+                    for r in rs:
                         pass
                     tabstat2 = [ p for p in con.info.get_table_access_stats() if p.table_id == tab_id ]
 
@@ -98,6 +116,15 @@ def test_1(act: Action, capsys):
                         idx -= (tabstat1[0].indexed if tabstat1[0].indexed else 0)
                         result_map[qry_txt, tab_nm] = (seq, idx)
 
+            except DatabaseError as e:
+                print( e.__str__() )
+                print(e.gds_codes)
+            finally:
+                if rs:
+                    rs.close() # <<< EXPLICITLY CLOSING CURSOR RESULTS
+                if ps:
+                    ps.free()
+
         '''
         print('q_map.items():')
         for k,v in q_map.items():
@@ -133,7 +160,8 @@ def test_1(act: Action, capsys):
                 print(qry_txt)
                 print('-' * 22)
                 print('Plan:')
-                print( '\n'.join([replace_leading(s) for s in q_map[qry_txt].split('\n')]) ) # explained plan, with preserving indents by replacing leading spaces with '#'
+                # Show explained plan, with preserving indents by replacing leading spaces with '.':
+                print( '\n'.join([replace_leading(s) for s in q_map[qry_txt].split('\n')]) )
                 print('')
         else:
             print(SUCCESS_MSG)