[PATCH] texi2any: Don't switch to subdir mode if '-' exists

[Arsen Arsenović]

* tp/texi2any.pl (output|out|o=s): If the filename argument is
specifically '-', ignore a possible ./- subdirectory.  This
prevents programs that generate info in a pipeline from being
confused in weird working directories.
---
Morning,

I was doing some math in Octave last night, and I typed in "help log",
only to be met with a strange error:

  octave:2> help log
  makeinfo: could not open -/octave-help-Q3PsCd.txt for writing: Permission 
denied
  makeinfo: could not open -/octave-help-Q3PsCd.txt for writing: Permission 
denied
  warning: help: Texinfo formatting filter exited abnormally; raw Texinfo 
source of help text follows...
  'log' is a built-in function from the file libinterp/corefcn/mappers.cc

This puzzled me for a bit, so I straced the makeinfo invocations Octave
was making and found that makeinfo stats - in my home directory.

I was quite confused by having a ~/- owned by root, but, it was there,
apparently.

The issue this introduced could be easily replicated as follows:

  ~$ mkdir --mode=000 ./-
  ~$ makeinfo --output=- --plaintext /dev/null
  makeinfo: could not open -/null.txt for writing: Permission denied

It is common practice to unconditionally interpret "-" as stdin despite
an existing file, however, and this patch fixes that behavior up, and
fixes Octave:

  ~$ mkdir --mode=000 ./-
  ~$ ./gnu/texinfo/pre-inst-env octave --silent
  octave:1> help log
  'log' is a built-in function from the file libinterp/corefcn/mappers.cc
  
   -- log (X)
       Compute the natural logarithm, ‘ln (X)’, for each element of X.
  
       To compute the matrix logarithm, see Linear Algebra.
  
       See also: exp, log1p, log2, log10, logspace.

OK for master?

Thanks in advance, have a lovely day.

 ChangeLog      | 8 ++++++++
 tp/texi2any.pl | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 04d3020001..b3f69b6eec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2023-03-08  Arsen Arsenović  <ar...@aarsen.me>
+
+       texi2any: Don't switch to subdir mode if '-' exists
+       * tp/texi2any.pl (output|out|o=s): If the filename argument is
+       specifically '-', ignore a possible ./- subdirectory.  This
+       prevents programs that generate info in a pipeline from being
+       confused in weird working directories.
+
 2023-03-07  Patrice Dumas  <pertu...@free.fr>
 
        * tp/Texinfo/Convert/HTML.pm (output_internal_links): determine if
diff --git a/tp/texi2any.pl b/tp/texi2any.pl
index 8d7af9554d..aad7ba4c3f 100755
--- a/tp/texi2any.pl
+++ b/tp/texi2any.pl
@@ -1009,7 +1009,7 @@ There is NO WARRANTY, to the extent permitted by 
law.\n"), "2022");
                      $format = 'plaintext' if (!$_[1] and $format eq 'info'); 
},
  'output|out|o=s' => sub {
     my $var = 'OUTFILE';
-    if ($_[1] =~ m:/$: or -d $_[1]) {
+    if ($_[1] ne '-' and ($_[1] =~ m:/$: or -d $_[1])) {
       set_from_cmdline($var, undef);
       $var = 'SUBDIR';
     }
-- 
2.39.2