Description

vstinner

opened on Sep 5, 2023

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Bug report

Example:

$ ./python -m test test_sys test_sys -m test_intern -v
(...)
0:00:00 load avg: 1.60 Run tests sequentially
0:00:00 load avg: 1.60 [1/2] test_sys
test_intern (test.test_sys.SysModuleTest.test_intern) ... ok

----------------------------------------------------------------------
Ran 1 test in 0.001s

OK
0:00:00 load avg: 1.60 [2/2] test_sys
test_intern (test.test_sys.SysModuleTest.test_intern) ... FAIL

======================================================================
FAIL: test_intern (test.test_sys.SysModuleTest.test_intern)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/python/3.12/Lib/test/test_sys.py", line 687, in test_intern
    self.assertTrue(sys.intern(s) is s)
AssertionError: False is not true

----------------------------------------------------------------------
(...)

Result: FAILURE

Linked PRs

• gh-108963: using random to generate unique string in sys.intern test #109491
• [3.12] gh-108963: using random to generate unique string in sys.intern test … #110216

Activity

1. vstinner

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   testsTests in the Lib/test dirTests in the Lib/test dir

   on Sep 5, 2023
2. vstinner commented on Sep 6, 2023

   

   vstinner

   on Sep 6, 2023

   MemberAuthor

   More actions

   @serhiy-storchaka: Oh, that another victim of regrtest trying to be nice :-) test_sys pass when run multiple times in the same process using this change:

   diff --git a/Lib/test/libregrtest/runtest.py b/Lib/test/libregrtest/runtest.py
   index 16ae04191d..249e331434 100644
   --- a/Lib/test/libregrtest/runtest.py
   +++ b/Lib/test/libregrtest/runtest.py
   @@ -436,7 +436,7 @@ def _load_run_test(result: TestResult, ns: Namespace) -> None:
        module_name = abs_module_name(result.test_name, ns.testdir)
    
        # Remove the module from sys.module to reload it if it was already imported
   -    sys.modules.pop(module_name, None)
   +    #sys.modules.pop(module_name, None)
    
        test_mod = importlib.import_module(module_name)
    
   

   The interesting part is that ./python -m test -R 3:3 test_sys doesn't fail since it doesn't remove the test module between two test iterations ;-)
3. serhiy-storchaka commented on Sep 6, 2023

   

   serhiy-storchaka

   on Sep 6, 2023

   Member

   More actions

   For reference, the module level counter was added in aee3486 to prevent test_intern failing when it is rerun in verbose mode. But if the module is reloaded, the counter is reset.

   One of solutions is to use the random module. Possibility of collisions in negligible.

   Other solution -- use timer in the hope that the computer is not fast enough to finish the whole test several times in the time resolution unit.

   We can also try to use id()s of some objects (self, globals(), locals()), but there is greater chance that all of them are allocated at exactly same address after reloading the module.

   test_subinterp_intern_dynamically_allocated fails for the same reason.
4. aisk commented on Sep 16, 2023

   

   aisk

   on Sep 16, 2023

   Member

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   Trying to change to using random.random() and it looks like it works well: #109491

   C:\cpython>python -m test test_sys test_sys
   Running Debug|x64 interpreter...
   0:00:00 Run 2 tests sequentially
   0:00:00 [1/2] test_sys
   0:00:04 [2/2] test_sys
   
   == Tests result: SUCCESS ==
   
   All 2 tests OK.
   
   Total duration: 8.9 sec
   Total tests: run=148 skipped=12
   Total test files: run=2/2
   Result: SUCCESS
   
5. vstinner

   changed the title [-]sys.test_intern() fails if run more than once in the same process[/-] [+]test_sys.test_intern() fails if run more than once in the same process[/+] on Sep 18, 2023
6. vstinner

   added

   needs backport to 3.12only security fixesonly security fixes

   and removed

   needs backport to 3.12only security fixesonly security fixes

   on Oct 2, 2023
7. vstinner

   added a commit that references this issue on Oct 2, 2023

   gh-108963: using random to generate unique string in sys.intern test (#…

   44b1e4e
8. vstinner

   closed this as completedon Oct 2, 2023
9. vstinner

   added a commit that references this issue on Oct 2, 2023

   pythongh-108963: using random to generate unique string in sys.intern…

   52c001d
10. Yhg1s

    added a commit that references this issue on Oct 2, 2023

    [3.12] gh-108963: using random to generate unique string in sys.inter…

    f911d7e
11. Glyphack

    added a commit that references this issue on Sep 2, 2024

    pythongh-108963: using random to generate unique string in sys.intern…

    34f3941

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