bug#73854: 29.4; tex-mode: unexpected and inconsistent behaviour of `tex-compile`, `tex-file`, and `tex-view`

bug#73854: 29.4; tex-mode: unexpected and inconsistent behaviour of `tex-compile`, `tex-file`, and `tex-view`

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

Basically, `tex-view` works, opening Evince, on a compiled .pdf only
after a .dvi is created.

Running 'emacs -Q' I evaluate the following in the scratch buffer, to
make it so that latex is compiled to pdf:
```
(setq tex-print-file-extension ".pdf"
      tex-dvi-view-command "evince"
      tex-dvi-print-command "lpr")
```
the last two lines are following the instructions on the description of
`tex-print-file-extension`.

I navigate to a simple .tex in an empty directory and press `C-c C-c`
which is bound by default to `tex-compile`, I press enter, as the
default is `pdflatex`, and the file compiles, creating a .pdf in the
directory. After that I press `C-c C-v`, which is bound to `tex-view`
but Evince does not open, instead I get the message "tex-print: No
appropriate ‘.dvi’ file could be found. If I press `C-c C-f`
(`tex-file`) after that, a .dvi file is created, and now `tex-view`
works, meaning it opens the .pdf with Evince.

The fact that `tex-view` works on the .pdf only when a .dvi is first
created seems like a bug.




In GNU Emacs 29.4 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.38,
 cairo version 1.16.0) of 2024-07-22, modified by Debian built on
 x86-ubc-01
Windowing system distributor 'The X.Org Foundation', version 11.0.12201009
System Description: Debian GNU/Linux 12 (bookworm)

Configured using:
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 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.4/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.4/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/libexec
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-libsystemd --with-pop=yes
 --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.4/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.4/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-mailutils
 --with-native-compilation --with-cairo --with-x=yes
 --with-x-toolkit=gtk3 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -ffile-prefix-map=/build/reproducible-path/emacs-29.4+1=. -fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
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Configured features:
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JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES
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Important settings:
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Major mode: LaTeX

Minor modes in effect:
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Load-path shadows:
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bug#73854: 29.4; tex-mode: unexpected and inconsistent behaviour of `tex-compile`, `tex-file`, and `tex-view`

[Eli Zaretskii]

> Date: Thu, 17 Oct 2024 18:36:19 +0000
> From:  Thalis Charakas via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Basically, `tex-view` works, opening Evince, on a compiled .pdf only
> after a .dvi is created.
> 
> Running 'emacs -Q' I evaluate the following in the scratch buffer, to
> make it so that latex is compiled to pdf:
> ```
> (setq tex-print-file-extension ".pdf"
>       tex-dvi-view-command "evince"
>       tex-dvi-print-command "lpr")
> ```
> the last two lines are following the instructions on the description of
> `tex-print-file-extension`.
> 
> I navigate to a simple .tex in an empty directory and press `C-c C-c`
> which is bound by default to `tex-compile`, I press enter, as the
> default is `pdflatex`, and the file compiles, creating a .pdf in the
> directory. After that I press `C-c C-v`, which is bound to `tex-view`
> but Evince does not open, instead I get the message "tex-print: No
> appropriate ‘.dvi’ file could be found. If I press `C-c C-f`
> (`tex-file`) after that, a .dvi file is created, and now `tex-view`
> works, meaning it opens the .pdf with Evince.
> 
> The fact that `tex-view` works on the .pdf only when a .dvi is first
> created seems like a bug.

Thanks.  Can you step with Edebug through tex-print in your case and
try to figure out what happens there that causes the error message?
There's some logic there which is supposed to verify that the current
buffer's print file is up-to-date:

    (if (and (not (equal (current-buffer) tex-last-buffer-texed))
	     (buffer-file-name)
	     ;; Check that this buffer's printed file is up to date.
	     (file-newer-than-file-p
	      (setq test-name (tex-append (buffer-file-name)
                                          tex-print-file-extension))
	      (buffer-file-name)))
	(setq print-file-name-dvi test-name))

Maybe something goes wrong there in your case?

(I don't have the requisite tools installed to try this myself,
sorry.)

bug#73854: 29.4; tex-mode: unexpected and inconsistent behaviour of `tex-compile`, `tex-file`, and `tex-view`

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

[-- Attachment #1: Type: text/plain, Size: 2439 bytes --]

On Sat, 19 Oct 2024 12:54:51 +0300 Eli Zaretskii <eliz@gnu.org> wrote:

>> Date: Thu, 17 Oct 2024 18:36:19 +0000
>> From:  Thalis Charakas via "Bug reports for GNU Emacs,
>>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>> 
>> Basically, `tex-view` works, opening Evince, on a compiled .pdf only
>> after a .dvi is created.
>> 
>> Running 'emacs -Q' I evaluate the following in the scratch buffer, to
>> make it so that latex is compiled to pdf:
>> ```
>> (setq tex-print-file-extension ".pdf"
>>       tex-dvi-view-command "evince"
>>       tex-dvi-print-command "lpr")
>> ```
>> the last two lines are following the instructions on the description of
>> `tex-print-file-extension`.
>> 
>> I navigate to a simple .tex in an empty directory and press `C-c C-c`
>> which is bound by default to `tex-compile`, I press enter, as the
>> default is `pdflatex`, and the file compiles, creating a .pdf in the
>> directory. After that I press `C-c C-v`, which is bound to `tex-view`
>> but Evince does not open, instead I get the message "tex-print: No
>> appropriate ‘.dvi’ file could be found. If I press `C-c C-f`
>> (`tex-file`) after that, a .dvi file is created, and now `tex-view`
>> works, meaning it opens the .pdf with Evince.
>> 
>> The fact that `tex-view` works on the .pdf only when a .dvi is first
>> created seems like a bug.
>
> Thanks.  Can you step with Edebug through tex-print in your case and
> try to figure out what happens there that causes the error message?
> There's some logic there which is supposed to verify that the current
> buffer's print file is up-to-date:
>
>     (if (and (not (equal (current-buffer) tex-last-buffer-texed))
> 	     (buffer-file-name)
> 	     ;; Check that this buffer's printed file is up to date.
> 	     (file-newer-than-file-p
> 	      (setq test-name (tex-append (buffer-file-name)
>                                           tex-print-file-extension))
> 	      (buffer-file-name)))
> 	(setq print-file-name-dvi test-name))
>
> Maybe something goes wrong there in your case?

I debugged this and the problem is that tex-print expects the variable
tex-print-file to be set, but (as its doc string says) it is set by
tex-region, tex-buffer and tex-file, which are all not commands run by
tex-compile, which is meant to run external programs (listed by
tex-compile-commands).  A simple fix is the following patch:


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: tex-compile patch --]
[-- Type: text/x-patch, Size: 461 bytes --]

diff --git a/lisp/textmodes/tex-mode.el b/lisp/textmodes/tex-mode.el
index 6fc49800018..acb5bb4b860 100644
--- a/lisp/textmodes/tex-mode.el
+++ b/lisp/textmodes/tex-mode.el
@@ -2530,6 +2530,7 @@ tex-compile
       (if (tex-shell-running)
           (tex-kill-job)
         (tex-start-shell))
+      (setq tex-print-file (expand-file-name (tex-main-file)))
       (tex-send-tex-command cmd dir))))

 (defun tex-start-tex (command file &optional dir)

[-- Attachment #3: Type: text/plain, Size: 161 bytes --]


But I'm not familiar with the tex-mode.el code and don't know if this
change might have unwanted consequences (though it seems prima facie
safe).

Steve Berman

bug#73854: 29.4; tex-mode: unexpected and inconsistent behaviour of `tex-compile`, `tex-file`, and `tex-view`

[Eli Zaretskii]

> From: Stephen Berman <stephen.berman@gmx.net>
> Cc: Thalis Charakas <thales1@protonmail.com>,  73854@debbugs.gnu.org
> Date: Sat, 19 Oct 2024 13:31:05 +0200
> 
> diff --git a/lisp/textmodes/tex-mode.el b/lisp/textmodes/tex-mode.el
> index 6fc49800018..acb5bb4b860 100644
> --- a/lisp/textmodes/tex-mode.el
> +++ b/lisp/textmodes/tex-mode.el
> @@ -2530,6 +2530,7 @@ tex-compile
>        (if (tex-shell-running)
>            (tex-kill-job)
>          (tex-start-shell))
> +      (setq tex-print-file (expand-file-name (tex-main-file)))
>        (tex-send-tex-command cmd dir))))
> 
>  (defun tex-start-tex (command file &optional dir)
> 
> But I'm not familiar with the tex-mode.el code and don't know if this
> change might have unwanted consequences (though it seems prima facie
> safe).

Thanks.

Stefan, do you agree with this fix?

bug#73854: 29.4; tex-mode: unexpected and inconsistent behaviour of `tex-compile`, `tex-file`, and `tex-view`

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

>> diff --git a/lisp/textmodes/tex-mode.el b/lisp/textmodes/tex-mode.el
>> index 6fc49800018..acb5bb4b860 100644
>> --- a/lisp/textmodes/tex-mode.el
>> +++ b/lisp/textmodes/tex-mode.el
>> @@ -2530,6 +2530,7 @@ tex-compile
>>        (if (tex-shell-running)
>>            (tex-kill-job)
>>          (tex-start-shell))
>> +      (setq tex-print-file (expand-file-name (tex-main-file)))
>>        (tex-send-tex-command cmd dir))))
>> 
>>  (defun tex-start-tex (command file &optional dir)
>> 
>> But I'm not familiar with the tex-mode.el code and don't know if this
>> change might have unwanted consequences (though it seems prima facie
>> safe).
>
> Stefan, do you agree with this fix?

No objections here.
Personally, I use `C-c C-c` to view the PDF (i.e. `C-c C-c` first to
compile the TeX file, then a second time to view the result).

So, maybe the patch below would also help.


        Stefan


diff --git a/lisp/textmodes/tex-mode.el b/lisp/textmodes/tex-mode.el
index 6fc49800018..f27bd1620e1 100644
--- a/lisp/textmodes/tex-mode.el
+++ b/lisp/textmodes/tex-mode.el
@@ -2212,6 +2212,7 @@ tex-compile-commands
      t "%r.dvi")
     ("xdvi %r &" "%r.dvi")
     ("\\doc-view \"%r.pdf\"" "%r.pdf")
+    ("evince %r.pdf &" "%r.pdf")
     ("xpdf %r.pdf &" "%r.pdf")
     ("gv %r.ps &" "%r.ps")
     ("yap %r &" "%r.dvi")