Re: Output to directory patch

[Ikumi Keita]

Hi Al,

>>>>> Al Haji-Ali <abdo.haji.ali@gmail.com> writes:
> On 07/03/2021, Ikumi Keita wrote:
>> Obviously the remaining cross dependency between `TeX-master-file' and
>> `TeX-master-output-dir' is the origin of these troubles. I recommend to
>> restrict call on `TeX-master-output-dir' in `TeX-master-file' within
>> cases that the extension matches output files.
> The inter-dependency between `TeX-master-output-dir' and
> `TeX-master-file` is not real, as you previously pointed out.

The cross dependency I talk about here is an implicit one through
`find-file-hook'. `TeX-master-file' calls `TeX-master-output-dir', which
calls `find-file-noselect', which in turn calls `find-file-hook'. AUCTeX
has the following code at the last of `VirTeX-common-initialization'.
,----
|   (add-hook 'find-file-hook
|             (lambda ()
|               ;; Check if we are looking at a new or shared file.
|               (when (or (not (file-exists-p (buffer-file-name)))
|                         (eq TeX-master 'shared))
|                 (TeX-master-file nil nil t))
|               (TeX-update-style t)) nil t))
`----
I suppose that you observed emacs asked the master file name when
opening compressed tex files. That inquiry was caused by this
`TeX-master-file' in the above `find-file-hook'.
I realized that it isn't precise to say that is the "origin" of the
troubles, nevertheless the dependency exists for sure.

>> Or it would be much nice if it is possible to remove the cross
>> dependency completely. Isn't it possible to implement
>> `TeX-master-output-dir' without calling `TeX-master-file' at all?
> The reason `TeX-master-output-dir' needs the name of master file (and
> the buffer of the master file) is because the value of TeX-output-dir
> should be obtained from that file and not from other sub-files.

How about stopping trying to obtain the value of `TeX-output-dir' from
master file? The purpose of my report 2[1] is to draw attention to the
existence of cross dependency (and to suggest to work on eliminating
it), and not to recommend to identify the proper value of
`TeX-output-dir'.
In my point of view,
- it is the user's responsibility to make sure that the main and sub
  files share the common value of `TeX-output-dir' and
- it's OK that your patch has some troubles such as ending up with error
  when the value of `TeX-output-dir' isn't coherent over the main and
  sub files (unless it causes serious problem such as deleting tex files
  or killing emacs session, of course).

[1] https://lists.gnu.org/r/auctex-devel/2021-02/msg00046.html

> Please find a patch to the `tex-build-only` branch attached. If you
> think the changes are reasonable, I will push them to my local repo so
> that Tassilo can pull them.

I confirmed that the updated patch doesn't have the problem I reported
in my last message, but I can't yet be sure whether other subtle
implicit cross dependency problem still remains and emerges under
unexpected circumstance or not...

>>> BTW, I added a note in `TeX-command-default` where the filename `name`
>>> is compared to the output of `TeX-region-file` to determine if the
>>> file comes from TeX-region-file or TeX-master-file. This is another
>>> reason why I believe passing file-fn to TeX-command-default is more
>>> appropriate.
>> 
>> Agreed. The current (unmodified) implementation is ugly, IMHO.
>> 
> I am happy to change it to a comparison based on the `file-fn`
> argument instead, if there's no better solution.

That's fine with me. Please go ahead. I expect other maintainers won't
oppose to it.

> In any case, if changing environment variables in AUCTeX is not
> desirable,

Changing environment varible itself is fine, but it seems that there is
no end if you deal with such small incompatibilities one by one.

> then maybe we can just mention in the eventual documentation of
> TeX-output-dir that adding the output directory to `TEXINPUTS` and
> `BIBINPUTS` might be needed in some cases (I personally do this in my
> private configuration).

Looks reasonable.

Regards,
Ikumi Keita