bug#59194: 29.0.50; Tramp autoloads and ordering

bug#59194: 29.0.50; Tramp autoloads and ordering

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

Package: Emacs
Version: 29.0.50


`tramp.el` has the following:

    ;;;###tramp-autoload
    (progn
      (defvar tramp--startup-hook nil
        "Forms to be executed at the end of tramp.el.")
      (put 'tramp--startup-hook 'tramp-suppress-trace t)
    
      (defmacro tramp--with-startup (&rest body)
        "Schedule BODY to be executed at the end of tramp.el."
        `(add-hook 'tramp--startup-hook (lambda () ,@body))))

and then various other Tramp files have autoloaded forms like:

    ;;;###tramp-autoload
    (tramp--with-startup
     (add-to-list 'tramp-methods
      ...))

The problem here is that the resulting `tramp-loaddefs.el` may or may
not be valid depending on the order in which it gets filled, which is
not something that's documented/guaranteed.


        Stefan

bug#59194: 29.0.50; Tramp autoloads and ordering

[Michael Albinus]

Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of
text editors" <bug-gnu-emacs@gnu.org> writes:

Hi Stefan,

> `tramp.el` has the following:
>
>     ;;;###tramp-autoload
>     (progn
>       (defvar tramp--startup-hook nil
>         "Forms to be executed at the end of tramp.el.")
>       (put 'tramp--startup-hook 'tramp-suppress-trace t)
>
>       (defmacro tramp--with-startup (&rest body)
>         "Schedule BODY to be executed at the end of tramp.el."
>         `(add-hook 'tramp--startup-hook (lambda () ,@body))))
>
> and then various other Tramp files have autoloaded forms like:
>
>     ;;;###tramp-autoload
>     (tramp--with-startup
>      (add-to-list 'tramp-methods
>       ...))
>
> The problem here is that the resulting `tramp-loaddefs.el` may or may
> not be valid depending on the order in which it gets filled, which is
> not something that's documented/guaranteed.

I'm aware of this. It was already reported on emacs-devel, see thread
starting with <87edvw7bjk.fsf@dataswamp.org>. In that case I've added
some variable declarations.

However, I don't know how to fix this in general.

>         Stefan

Best regards, Michael.

bug#59194: 29.0.50; Tramp autoloads and ordering

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

>> `tramp.el` has the following:
>>
>>     ;;;###tramp-autoload
>>     (progn
>>       (defvar tramp--startup-hook nil
>>         "Forms to be executed at the end of tramp.el.")
>>       (put 'tramp--startup-hook 'tramp-suppress-trace t)
>>
>>       (defmacro tramp--with-startup (&rest body)
>>         "Schedule BODY to be executed at the end of tramp.el."
>>         `(add-hook 'tramp--startup-hook (lambda () ,@body))))
>>
>> and then various other Tramp files have autoloaded forms like:
>>
>>     ;;;###tramp-autoload
>>     (tramp--with-startup
>>      (add-to-list 'tramp-methods
>>       ...))
>>
>> The problem here is that the resulting `tramp-loaddefs.el` may or may
>> not be valid depending on the order in which it gets filled, which is
>> not something that's documented/guaranteed.
>
> I'm aware of this. It was already reported on emacs-devel, see thread
> starting with <87edvw7bjk.fsf@dataswamp.org>. In that case I've added
> some variable declarations.
>
> However, I don't know how to fix this in general.

Can you arrange to load `tramp-loaddefs.el` only after some
initialization (e.g. creation of `tramp-foo-methods` or equivalent) so
you can do just:

    ;;;###tramp-autoload
    (add-to-list 'tramp-foo-methods ...)

If those methods really need to be registered later, then `tramp.el` can
finish with a short loop moving the methods from `tramp-foo-methods` to
`tramp-methods`.

Would that make sense?


        Stefan