Re: [guile-emacs] Circular require problem

[Robin Templeton <robin@terpri.org>]

Left Right <olegsivokon@gmail.com> writes:

> Hello, I've asked at #guile IRC channel and was told this is the right
> place to report these.
>
> So, I've built Guile-2.2 and Guile-Emacs. Vanilla Emacs didn't start
> at first due to:
>
> (provide 'calendar)
> (require 'cal-menu)
>
> lines in cal-menu.el. This is because calendar requires cal-menu and
> cal-menu requires calendar. It seems like the strategy in these
> situation with Emacs Lisp is to put a "fake" provide statement in the
> beginning of the file which provides the library, knowing that there's
> the second "real" provide statement in the end of the file. I've
> witnessed this same problem with couple more libraries, ERC being one
> of them. The first thing I tried was:
>
> (unless (featurep 'cal-menu) (require 'cal-menu))
>
> Which, in some cases magically solved the problem, but not in other cases.
>
> But I don't think it is useful to mimic Emacs behavior wrt circular
> require. I think it would be better to make circular require possible
> by remembering what libraries had already been required.

Thank you for the detailed report! This problem has been fixed in the
current version of Guile-Emacs.

I had modified `load' to compile and execute entire files at once, but
the expression-by-expression evaluation normally performed by `load' is
important for breaking `require' cycles like the one you encountered.
Top-level `require' forms are evaluated at compile time but `provide'
forms aren't, so when `load' compiles the whole file at once, early
`provide' forms can never take effect at the right time.

Additionally, some packages simply don't `require' all their
dependencies and can't be byte-compiled cleanly. To support such
packages, `load' now loads source files using an interpreter, just as
standard Emacs does. Guile-Emacs will support automatic compilation
again in the future, but it will take some time to implement in a
completely compatible way.

> I have more problems to report. I've tried loading some popular Emacs
> packages, such as Org, SLIME, ESS and CEDET, and few others, but none
> of that worked. Only relatively large library that loaded was Pymacs,
> but it affected the rest of the code somehow so that nothing else
> would compile any more.

Org, SLIME and ESS all work for me with the current version. (I haven't
tested CEDET or Pymacs.)

> There was another problem with eval-buffer, where (add-to-list
> 'load-path ...) with the following (require ...) sexp wouldn't work,
> but if evaluated sexp after sexp they magically worked.

This should be fixed now as well.

> I have saved backtrace and crash messages, and I could probably
> produce more / more specific error messages if I knew better how to
> debug. The regular backtrace buffer doesn't seem to be particularly
> useful (too much technical info, which is difficult to trace back to
> the source of the problem).

This is now fixed.

Thanks,
Robin
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