Flaky test with exception: access violation writing on Windows

[StrikerRUS]

In test_plot_split_value_histogram sometimes WindowsError: exception: access violation writing occurs

LightGBM/tests/python_package_test/test_plotting.py

Line 63 in 164818b

def test_plot_split_value_histogram(self):

For the moment of creating this issue I saw it two times: in #3380 and #3397.

================================== FAILURES ===================================
__________________ TestBasic.test_plot_split_value_histogram __________________

self = <test_plotting.TestBasic testMethod=test_plot_split_value_histogram>

    @unittest.skipIf(not MATPLOTLIB_INSTALLED, 'matplotlib is not installed')
    def test_plot_split_value_histogram(self):
>       gbm0 = lgb.train(self.params, self.train_data, num_boost_round=10)

..\tests\python_package_test\test_plotting.py:64: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
C:\Miniconda\envs\test-env\lib\site-packages\lightgbm\engine.py:231: in train
    booster = Booster(params=params, train_set=train_set)
C:\Miniconda\envs\test-env\lib\site-packages\lightgbm\basic.py:2010: in __init__
    self.__get_eval_info()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <lightgbm.basic.Booster object at 0x000000000A248B88>

    def __get_eval_info(self):
        """Get inner evaluation count and names."""
        if self.__need_reload_eval_info:
            self.__need_reload_eval_info = False
            out_num_eval = ctypes.c_int(0)
            # Get num of inner evals
            _safe_call(_LIB.LGBM_BoosterGetEvalCounts(
                self.handle,
                ctypes.byref(out_num_eval)))
            self.__num_inner_eval = out_num_eval.value
            if self.__num_inner_eval > 0:
                # Get name of evals
                tmp_out_len = ctypes.c_int(0)
                reserved_string_buffer_size = 255
                required_string_buffer_size = ctypes.c_size_t(0)
                string_buffers = [
                    ctypes.create_string_buffer(reserved_string_buffer_size) for i in range_(self.__num_inner_eval)
                ]
                ptr_string_buffers = (ctypes.c_char_p * self.__num_inner_eval)(*map(ctypes.addressof, string_buffers))
                _safe_call(_LIB.LGBM_BoosterGetEvalNames(
                    self.handle,
                    self.__num_inner_eval,
                    ctypes.byref(tmp_out_len),
                    reserved_string_buffer_size,
                    ctypes.byref(required_string_buffer_size),
>                   ptr_string_buffers))
E               WindowsError: exception: access violation writing 0x00007FF9085F04DE

C:\Miniconda\envs\test-env\lib\site-packages\lightgbm\basic.py:3182: WindowsError

Both times it was in the following Windows job

LightGBM/.vsts-ci.yml

Lines 119 to 121 in 164818b

	sdist:
	TASK: sdist
	PYTHON_VERSION: 2.7

[jameslamb]

is this different from #1818 ?

[StrikerRUS]

@jameslamb Yes, this test started to fail only some days ago and it is VS while that one is MinGW.

[jameslamb]

oh ok got it

[guolinke]

maybe there are some memory leakages. @shiyu1994 can you take a look when you have time?

[StrikerRUS]

I guess these recent PRs may contain a bug: #2850, #3022.

[github-actions]

This issue has been automatically locked since there has not been any recent activity since it was closed. To start a new related discussion, open a new issue at https://github.com/microsoft/LightGBM/issues including a reference to this.