Fw: bug in texi2dvi, and hack patch

[Eric Blake]

This was sent to a cygwin list, but is more properly a texinfo problem in
the texi2dvi script (version 4.7).  $COMSPEC has meaning in djgpp and
perhaps mingw, but is just a worthless environment variable when inherited
into cygwin.  Instead of using $COMSPEC for determining the path
separator, you should use autoconf's approach (look at any recent
configure script generated by autoconf 2.59 for this snippet):

if test "${PATH_SEPARATOR+set}" != set; then
  echo "#! /bin/sh" >conf$$.sh
  echo  "exit 0"   >>conf$$.sh
  chmod +x conf$$.sh
  if (PATH="/nonexistent;."; conf$$.sh) >/dev/null 2>&1; then
    PATH_SEPARATOR=';'
  else
    PATH_SEPARATOR=:
  fi
  rm -f conf$$.sh
fi

Dave's other point that you are incorrectly dividing the path at ' ' in
findprog() is also valid, you should instead be temporarily setting
IFS=$PATH_SEPARATOR instead.  Additionally, according to autoconf, `test
-x' is not portable.  Your best bet may be to make texi2dvi a generated
file from texi2dvi.in, and let autoconf determine @PATH_SEPARATOR@ and
even the location of tex up front at configure time, rather than
re-locating it every invocation of texi2dvi.

I was able to avoid hacking texi2dvi by adding "unset COMSPEC" to my
cygwin ~/.bashrc.  Even with spaces in my $PATH, tex happened to be
installed in one of the directories that did not have a space.

-- 
Life is short - so eat dessert first!

Eric Blake             address@hidden

To: cygwin at cygwin dot com
From: David Abrahams <dave at boost-consulting dot com>
Subject: bug in texi2dvi, and hack patch
Date: Sat, 15 Jan 2005 13:42:40 -0500

The latest /bin/texi2dvi contains (at line 102):

  # Systems which define $COMSPEC or $ComSpec use semicolons to separate
  # directories in TEXINPUTS.
  if test -n "$COMSPEC$ComSpec"; then
    path_sep=";"
  else
    path_sep=":"
  fi

I think I know what this is *trying* to accomplish, but I think it's
misguided.  At least on my system, all the environment variables defined
for my NT shell also show up in Cygwin, appropriately translated to use
":" separators.  So the above messes everything up when findprog(),
shown below, tries to locate the "tex" program:

findprog () {
  foundprog=false
  for dir in `echo $PATH | tr "$path_sep" " "`; do
    if test -x "$dir/$1"; then  # does anyone still need test -f?
      foundprog=true
      break
    fi
  done
  $foundprog
}

Paths end up being broken at spaces.  I'm actually a little concerned
about the code above because it seems to me that even after we fix the
path_sep problem it will fail to work correctly with paths containing
spaces.  I'm certain it's not the right long-term fix, but the little
hack patch I needed to get going again was to change line 105 from:

    path_sep=";"

to

    path_sep=":"

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com