[ruby-core:104651] [Ruby master Bug#17429] Prohibit include/prepend in refinement modules

[shugo@ruby-lang.org]

Issue #17429 has been updated by shugo (Shugo Maeda).


Eregon (Benoit Daloze) wrote in #note-20:
> One more issue reported due these confusing semantics of include/prepend inside `refine`: #18021.
> 
> I suggest we warn in 3.1, raise in 3.2.
> And I suggest to add `Refinement#import`, because:
> * `mix` seems to imply other things, and if it's ever added to Module with different semantics we will just get more confusion.
> * `include` seems likely to cause confusion because the behavior would not be Module#include-like. It is also potentially backward-incompatible, raises the question about what would happen for `prepend` and consistency. And finnaly `include` would not longer mean "define higher in the ancestor" for this context, i.e., defining the same method in the refine block would replace, not just override).

I've implemented Refinement#import in https://github.com/shugo/ruby/pull/3

In the current implementation, the module in cref is replaced with the refinement like Module#dup, so constants in the imported module are not accessible from the copied methods.
It would be possible to support constant access with a hack on cref, but I'm afraid it may bring new problems.

Maybe Refinement#import_methods is a better name if we keep the current behavior.


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Bug #17429: Prohibit include/prepend in refinement modules
https://bugs.ruby-lang.org/issues/17429#change-92960

* Author: shugo (Shugo Maeda)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
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include/prepend in refinement modules has implementation difficulties such as #17007 and #17379, and tends to be misleading like #17374.
How about to prohibit it in future versions?

Method copy like #17380 may be more convenient, but it's confusing to use names include and prepend because semantics is different from the original ones.




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