obs_module_unload was never properly documented, so some plugins use it
to free resources, some use it to save data, etc. While libobs tries to
ensure all objects are shut down and destroyed before calling unload, if
another plugin is holding a strong reference, or if a reference leak has
occurred, libobs may need to call back into a plugin-provided object's
destroy function even after obs_module_unload has returned. If the
plugin has freed memory or other resources needed for the callback then
this likely results in a crash.
Going forward, we should document that obs_module_unload is now intended
only for saving data and releasing references, and that calling libobs
after it returns is not allowed. For cases where resource cleanup is
actually needed (for example, an external out of process helper needs to
be shut down or a release call to a hardware driver), a new
obs_module_destroy callback is intended to be added in a future version.
obs_find_modules2 allows the ability to get the module name in the
callback, and the change to obs_find_modules2 also adds the ability to
find out whether any modules failed to load or not.
Richard Stanway