bug#64526: 30.0.50; jit-compilation and multiple function definitions

bug#64526: 30.0.50; jit-compilation and multiple function definitions

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Package: Emacs
Version: 30.0.50


Say you have a file ~/tmp/foo.el:

    ;;  -*- lexical-binding: t; -*-
    (defun sm-foo1 (a) (list a 1))
    (defun sm-foo1 (a) (list a 2))

which you byte-compile into ~/tmp/foo.elc, and then you do:

    emacs -Q -l ~/tmp/foo
    M-: (sm-foo1 'a) RET

you'll usually get `(a 2)` (and that's what we expect).  But if you enable
native compilation and erase the `eln-cache` before trying it out you
may get `(a 1)` because when the `.eln` file is reloaded on top of the
`.elc` definitions, `comp--late-register-subr` will skip the second
definition :-(

I suspect similar problems can occur when the two definitions are placed
in different files (and those files are loaded "at the same time",
i.e. the second file is loaded before the native-compilation of the
first file finishes) since `comp-deferred-pending-h` does not pay
attention to the file names.  :-(


        Stefan

bug#64526: 30.0.50; jit-compilation and multiple function definitions

[Andrea Corallo]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> Package: Emacs
> Version: 30.0.50
>
>
> Say you have a file ~/tmp/foo.el:
>
>     ;;  -*- lexical-binding: t; -*-
>     (defun sm-foo1 (a) (list a 1))
>     (defun sm-foo1 (a) (list a 2))
>
> which you byte-compile into ~/tmp/foo.elc, and then you do:
>
>     emacs -Q -l ~/tmp/foo
>     M-: (sm-foo1 'a) RET
>
> you'll usually get `(a 2)` (and that's what we expect).  But if you enable
> native compilation and erase the `eln-cache` before trying it out you
> may get `(a 1)` because when the `.eln` file is reloaded on top of the
> `.elc` definitions, `comp--late-register-subr` will skip the second
> definition :-(

Hi Stefan,

are we sure about this? Is this reproducible?

Thanks

  Andrea

> I suspect similar problems can occur when the two definitions are placed
> in different files (and those files are loaded "at the same time",
> i.e. the second file is loaded before the native-compilation of the
> first file finishes) since `comp-deferred-pending-h` does not pay
> attention to the file names.  :-(
>
>
>         Stefan

bug#64526: 30.0.50; jit-compilation and multiple function definitions

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

>> Package: Emacs
>> Version: 30.0.50
>>
>>
>> Say you have a file ~/tmp/foo.el:
>>
>>     ;;  -*- lexical-binding: t; -*-
>>     (defun sm-foo1 (a) (list a 1))
>>     (defun sm-foo1 (a) (list a 2))
>>
>> which you byte-compile into ~/tmp/foo.elc, and then you do:
>>
>>     emacs -Q -l ~/tmp/foo
>>     M-: (sm-foo1 'a) RET
>>
>> you'll usually get `(a 2)` (and that's what we expect).  But if you enable
>> native compilation and erase the `eln-cache` before trying it out you
>> may get `(a 1)` because when the `.eln` file is reloaded on top of the
>> `.elc` definitions, `comp--late-register-subr` will skip the second
>> definition :-(
>
> Hi Stefan,
>
> are we sure about this? Is this reproducible?

Yes, the above recipe reproduces it on my machine at least.


        Stefan

bug#64526: 30.0.50; jit-compilation and multiple function definitions

[Andrea Corallo]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>> Package: Emacs
>>> Version: 30.0.50
>>>
>>>
>>> Say you have a file ~/tmp/foo.el:
>>>
>>>     ;;  -*- lexical-binding: t; -*-
>>>     (defun sm-foo1 (a) (list a 1))
>>>     (defun sm-foo1 (a) (list a 2))
>>>
>>> which you byte-compile into ~/tmp/foo.elc, and then you do:
>>>
>>>     emacs -Q -l ~/tmp/foo
>>>     M-: (sm-foo1 'a) RET
>>>
>>> you'll usually get `(a 2)` (and that's what we expect).  But if you enable
>>> native compilation and erase the `eln-cache` before trying it out you
>>> may get `(a 1)` because when the `.eln` file is reloaded on top of the
>>> `.elc` definitions, `comp--late-register-subr` will skip the second
>>> definition :-(
>>
>> Hi Stefan,
>>
>> are we sure about this? Is this reproducible?
>
> Yes, the above recipe reproduces it on my machine at least.

Okay, will look at thanks.

  Andrea