TwinModel instance keep allocating memory when used in a loop

[lboucin]

🔍 Before submitting the issue

• I have searched among the existing issues
• I am using a Python virtual environment

🐞 Description of the bug

When instantiating a TwinModel in a loop, the allocated memory keep increasing.

📝 Steps to reproduce

import os
import tracemalloc
from pytwin import TwinModel

tracemalloc.start()
snapshot = tracemalloc.take_snapshot()

twin_file = os.path.join("path_to_a_twin_model_with_tbrom.twin")
for i in range(1, 100):
twin_model = TwinModel(model_filepath=twin_file)
snapshot2 = tracemalloc.take_snapshot()
top_stats = snapshot2.compare_to(snapshot, 'lineno')
stat_tbrom_read_basis = top_stats[0]
print(stat_tbrom_read_basis)

💻 Which operating system are you using?

Windows

📀 Which ANSYS version are you using?

NA

🐍 Which Python version are you using?

3.9

📦 Installed packages

certifi==2023.7.22
charset-normalizer==3.3.2
colorama==0.4.6
coverage==7.3.2
cycler==0.11.0
exceptiongroup==1.1.3    
fonttools==4.38.0        
idna==3.4
imageio==2.31.2
iniconfig==2.0.0
kiwisolver==1.4.5        
matplotlib==3.5.3        
numpy==1.21.1
packaging==23.2
pandas==1.3.5
Pillow==9.5.0
platformdirs==4.0.0      
pluggy==1.3.0
pooch==1.8.0
pyparsing==3.1.1
pytest==7.4.3
pytest-cov==4.1.0
python-dateutil==2.8.2
-e git+https://github.com/ansys/pytwin@16cf78a84ed27a2881d0c7781a8afe66750a76e9#egg=pytwin
pytz==2023.3.post1
pyvista==0.38.6
pywin32==306
requests==2.31.0
scooby==0.7.3
six==1.16.0
tomli==2.0.1
tqdm==4.66.1
urllib3==2.0.7
vtk==9.3.0

[lboucin]

Adding the following statement twin_model._tbroms = None at the end of the loop solve the issue, see below:

[lboucin]

Investigations: We are registering the __del__ method of the TwinModel with the atexit module in order to avoid the settings module tries to delete pytwin temp folder of the process before the log file of the TwinRuntime object owned by the TwinModel has been closed. This has a side effect which is that a TwinModel instance is referenced by the atexit module and thus preventing the garbage collector to collect and free the TwinModel at the end of the loop.

[lboucin]

@chrpetre see proposed solution in PR #130