semantics.at test failures with ksh Version M-12/28/93d

[Paul Eggert]

On Solaris 8 I tested Autoconf with dtksh as follows:

CONFIG_SHELL=/usr/dt/bin/dtksh dtksh ./testsuite

and got failures like this:

 54: semantics.at:171  FAILED near `semantics.at:171'
 55: semantics.at:189  FAILED near `semantics.at:189'

I tracked it down to a bug in dtksh (which claims that it is Korn
Shell Version M-12/28/93d).  dtksh mishandles variable expansion on
1024-byte buffer boundaries.  For example, if you run the following
script with dtksh, the output incorrectly ends in "x":

abcde=abcde
cat <<CEOF
xxxxxxxxxxxxxxxxxxxxx
xxxxx
xxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx${abcde}
CEOF

I have reported this bug to Sun (case number 62917825).
The same bug occurs in Solaris 9 early access.

I worked around the problem by setting ac_max_here_lines=12 in my
environment; this caused all the Autoconf tests to succeed.  However,
the real bug is not related to the number of lines, it is related to
the number of bytes.

Currently, lib/autoconf/general.m4 says:

   # Maximum number of lines to put in a shell here document.
   # This variable seems obsolete.  It should probably be removed, and
   # only ac_max_sed_lines should be used.
   : ${ac_max_here_lines=38}

I'm not sure that the variable is obsolete, since it was useful to me
in working around the dtksh bug, and that bug was really in the shell,
not in sed (though the document in question was for a sed script).

On the other hand I was using dtksh mostly as a stress test for
Autoconf, so this problem is probably low priority.