Subject: bug#69953: [PATCH] Remove duplicated asserts and checks

From: Eli Zaretskii <[email-masked]>
Date: Sat, 23 Mar 2024 09:15:04 +0200

> Date: Sat, 23 Mar 2024 03:27:34 +0000
> From: Sergey Vinokurov <[email-masked]>
> 
> I noticed that emacs-module.c contains duplicate 
> module_non_local_exit_check() checks and 
> module_assert_thread/module_assert_env asserts, mostly performed at the 
> same point in program sequentially.
> 
> The module_non_local_exit_check() checks happen in 
> MODULE_HANDLE_NONLOCAL_EXIT and MODULE_FUNCTION_BEGIN_NO_CATCH macros. 
> The MODULE_HANDLE_NONLOCAL_EXIT is never used by itself, only as part of 
> MODULE_FUNCTION_BEGIN which starts with MODULE_FUNCTION_BEGIN_NO_CATCH 
> that performs the check.
> 
> In addition, there're 6 "Implementation of runtime and environment 
> functions" rules outlined where MODULE_HANDLE_NONLOCAL_EXIT should be 
> called at step 4 but module_non_local_exit_check() is supposed to have 
> already happened at step 3 so documentation does not seem to intend for 
> the check to be repeated in MODULE_HANDLE_NONLOCAL_EXIT.
> 
> Regarding asserts my observation is that module_non_local_exit_check() 
> already contains module_assert_thread and module_assert_env so there's 
> no need to do asserts if first thing we do is call 
> module_non_local_exit_check.

Thanks, but why is that a problem?  module_assertions is false by
default, and the function to turn on module assertions is not even
documented in the ELisp manual.  IOW, this is a debugging aid which
will rarely if at all activated, and if it is, that's on purpose by
the programmer who is investigating some tricky problem.  Why is it a
problem to have too many assertions, which might help that programmer
find a bug?

I added Daniel and Philipp to the discussion, in case they have
comments to this proposal.