From da0580b307a1772f5e7364e97a0426d553b16d6d Mon Sep 17 00:00:00 2001
From: pavel-zotov <p519446@yandex.ru>
Date: Sat, 18 Jan 2025 16:26:13 +0300
Subject: [PATCH] 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 | 85 ++++++++++++++++++++++++------------
 1 file changed, 56 insertions(+), 29 deletions(-)

diff --git a/tests/bugs/core_6048_test.py b/tests/bugs/core_6048_test.py
index b83265e6..e0acd313 100644
--- a/tests/bugs/core_6048_test.py
+++ b/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
@@ -125,39 +132,59 @@ def test_1(act: Action, capsys):
             print( e.__str__() )
 
         cur2 = con2.cursor()
-        ps = cur2.prepare('select mon$crypt_page, mon$crypt_state from mon$database')
+        ps, rs = None, None
 
-        # This will store different number of pages which are currently encrypted.
-        # When length of this set will exceed ENCRYPTING_PAGES_MIN_CNT then we break from loop:
-        #
-        encrypting_pages_set = set()
-        waiting_in_loop = -1
-        while encryption_started:
-            t2=py_dt.datetime.now()
-            d1=t2-t1
-            waiting_in_loop = d1.seconds*1000 + d1.microseconds//1000
-            if waiting_in_loop > MAX_WAITING_ENCR_FINISH:
-                print(f'TIMEOUT EXPIRATION: encryption took {d1.seconds*1000 + d1.microseconds//1000} ms which exceeds limit = {MAX_WAITING_ENCR_FINISH} ms.')
-                break
+        try:
+            ps = cur2.prepare('select mon$crypt_page, mon$crypt_state from mon$database')
 
-            cur2.execute(ps)
-            crypt_page, crypt_state = cur2.fetchone()
-            con2.commit()
+            # This will store different number of pages which are currently encrypted.
+            # When length of this set will exceed ENCRYPTING_PAGES_MIN_CNT then we break from loop:
+            #
+            encrypting_pages_set = set()
+            waiting_in_loop = -1
+            while encryption_started:
+                t2=py_dt.datetime.now()
+                d1=t2-t1
+                waiting_in_loop = d1.seconds*1000 + d1.microseconds//1000
+                if waiting_in_loop > MAX_WAITING_ENCR_FINISH:
+                    print(f'TIMEOUT EXPIRATION: encryption took {d1.seconds*1000 + d1.microseconds//1000} ms which exceeds limit = {MAX_WAITING_ENCR_FINISH} ms.')
+                    break
 
-            # 0 = non crypted;
-            # 1 = has been encrypted;
-            # 2 = is DEcrypting;
-            # 3 = is Encrypting;
-            if crypt_state == RUNNING_ENCRYPTING_STATE:
-                encrypting_pages_set.add(crypt_page,)
+                # ::: 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 = cur2.execute(ps)
+                for r in rs:
+                    crypt_page, crypt_state = r[:2]
+    
+                con2.commit()
 
-            if crypt_state == COMPLETED_ENCRYPTION_STATE:
-                encryption_finished = True
-                break
-            elif len(encrypting_pages_set) > ENCRYPTING_PAGES_MIN_CNT:
-                break
-            else:
-                time.sleep(0.5)
+                # 0 = non crypted;
+                # 1 = has been encrypted;
+                # 2 = is DEcrypting;
+                # 3 = is Encrypting;
+                if crypt_state == RUNNING_ENCRYPTING_STATE:
+                    encrypting_pages_set.add(crypt_page,)
+
+                if crypt_state == COMPLETED_ENCRYPTION_STATE:
+                    encryption_finished = True
+                    break
+                elif len(encrypting_pages_set) > ENCRYPTING_PAGES_MIN_CNT:
+                    break
+                else:
+                    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()
 
         # ---------------------------------------------------------