[Helper] Added cleanup callback

[bakpaul]

This pr aims at fixing the crash on exit for some python scene. It was due to the cache of the Sofa python module not being cleaned up correctly (deleted after the interpreter). This is corrected here by insuring that the interpreter is correcty released through cleanup callback (see the SofaPython3 pr for more insights)

---

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---

Reviewers will merge this pull-request only if

• it builds with SUCCESS for all platforms on the CI.
• it does not generate new warnings.
• it does not generate new unit test failures.
• it does not generate new scene test failures.
• it does not break API compatibility.
• it is more than 1 week old (or has fast-merge label).

[sofabot]

[ci-depends-on] detected during build #1.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG 7359fb0f775997a5607bb7f61f20e4f31ce9d9b4

[bakpaul]

[ci-build][with-all-tests]

[sofabot]

[ci-depends-on] detected during build #2.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG 7359fb0f775997a5607bb7f61f20e4f31ce9d9b4

[sofabot]

[ci-depends-on] detected during build #3.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG 7359fb0f775997a5607bb7f61f20e4f31ce9d9b4

[sofabot]

[ci-depends-on] detected during build #4.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG 7359fb0f775997a5607bb7f61f20e4f31ce9d9b4

[alxbilger]

I wonder if Sofa.Helper is the right place to call a plugin clean up...

[bakpaul]

It was asked by @fredroy and it makes sens because the plugin manager belongs to Sofa.Helper

[alxbilger]

Yes, but your goal is to clean up plugins, not the plugin manager. For example, you will clean up SofaPython3 inside the Sofa.Helper cleanup function. I am not saying it is not the right thing to do, I am just questioning ...

[bakpaul]

My first though was to put it at the very end of the main function, both are justifiable. But I guess that conceptually, the cleanup order shouldn't matter, the simulation is over, we are just cleaning after us...

[fredroy]

Why not inside the destructor of PluginManager ? (if it is ever called 🥴)

[bakpaul]

We don't want it to be in a static instance, this fix aims at cleaning the static cache before the dynamically allocated python interpreter... So no, it is necessary to have it explicitly called.

[sofabot]

[ci-depends-on] detected during build #5.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG 7359fb0f775997a5607bb7f61f20e4f31ce9d9b4

[bakpaul]

@damienmarchal , discussions during the SOFA-dev meeting lead to a question over the developed design and your opinion is needed.

The problem was that some scenes tests where crashing at exit. This is due to the SofaPython3 cache (s_objectcache there https://github.com/sofa-framework/SofaPython3/blob/1b5d271aa21df06c4c5ab75599e364adb0c1e9be/Plugin/src/SofaPython3/DataHelper.cpp#L252C1-L252C73) . The problem was that this is a static object containing python objects and is thus cleaned at the very end of the program exit, after the python interpreter, which is not authorized.

To fix it, following pybind11 suggestions I've added a member to the module Sofa.Core that insured that the cleanup is called while the interpreter is still alive (see the PR sofa-framework/SofaPython3#425). But is was not enough because the interpreter is not cleaned correctly either : the static method "Release" of SofaPython3, in charge of cleaning up python and deleting the interpreter was never called when launching scene in runSofa.

This lead to the need of cleaning up explicitly the plugin before exiting the main function. This design was not liked by every dev, some wanting a Raii-like cleanup, in the destructor of some member, which is in my mind not possible because the interpreter instance is static in the SofaPython3 plugin and thus we have no guaranty that it would not be deleted before any other static member.

[sofabot]

[ci-depends-on] detected during build #6.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG e37c070cf814e019631b2a09a7f2e34b3d8946f9

[bakpaul]

[ci-build][with-all-tests]

[sofabot]

[ci-depends-on] detected during build #6.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG e37c070cf814e019631b2a09a7f2e34b3d8946f9

[sofabot]

[ci-depends-on] detected during build #7.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG e37c070cf814e019631b2a09a7f2e34b3d8946f9

[sofabot]

[ci-depends-on] detected during build #9.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG e37c070cf814e019631b2a09a7f2e34b3d8946f9

[sofabot]

[ci-depends-on] detected during build #10.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG 68f14ba14c960c04c536912ac250549c10ae5e57

[sofabot]

[ci-depends-on] detected during build #11.

To unlock the merge button, you must

• Merge or close Add cleanup to core and ensure that the cleanup happens in runSofa SofaPython3#425
  For this build, SofaPython3/ExternalProjectConfig.cmake.in will be edited by builders with
  GIT_REPOSITORY https://github.com/sofa-framework/SofaPython3
  GIT_TAG f7af4f78a5111fed68705eeb588983e42d6cdc85

[bakpaul]

[ci-build][with-all-tests][force-full-build]