Fix ASAN crash by avoiding decimal module in import tests

The _decimal C extension has global state (mpd_setminalloc) that cannot
handle being loaded in multiple interpreters. When the import registry
contained decimal, it would be applied to subinterpreters causing memory
corruption detected by AddressSanitizer.

Replace decimal with textwrap (pure Python) in import_in_sys_modules_test.

Author: benoitc

test/py_import_SUITE.erl

@@ -638,26 +638,30 @@ registry_applied_to_subinterp_test(_Config) ->
 %% After calling py:import, the module should be in the interpreter's
 %% sys.modules dictionary. We verify this by checking that calling
 %% a function from the module works (which requires it to be imported).
+%%
+%% Note: We use textwrap (pure Python) instead of decimal because the
+%% _decimal C extension has global state that crashes in subinterpreters.
 import_in_sys_modules_test(_Config) ->
     %% Clear registry
     ok = py_import:clear_imports(),
 
-    %% Import a module
-    ok = py_import:ensure_imported(decimal),
+    %% Import a pure Python module (avoid C extensions like decimal
+    %% which have global state that crashes in subinterpreters)
+    ok = py_import:ensure_imported(textwrap),
 
     %% Verify the import worked by calling a function
-    {ok, _} = py:call(decimal, 'Decimal', [<<"3.14">>]),
+    {ok, _} = py:call(textwrap, fill, [<<"Hello world">>, 5]),
 
     %% Now check sys.modules using the same process (important!)
     %% We use exec to define a helper, then eval to check
     ok = py:exec(<<"
 import sys
-_test_decimal_in_sys = 'decimal' in sys.modules
+_test_textwrap_in_sys = 'textwrap' in sys.modules
 ">>),
-    {ok, InSysModules} = py:eval(<<"_test_decimal_in_sys">>),
+    {ok, InSysModules} = py:eval(<<"_test_textwrap_in_sys">>),
     ?assertEqual(true, InSysModules),
 
-    ct:pal("py:import correctly adds module to sys.modules").
+    ct:pal("py_import:ensure_imported correctly adds module to sys.modules").
 
 %% @doc Test that ETS registry and sys.modules stay in sync
 %%