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

[Akim Demaille]

| 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

Incredible!  As usual, would you report this limitation in the doc,
please?

| 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.

Yep, but anyway, we are loaded with weird heuristic to work around
such bugs.  Not all are full bullet proof.

| 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).

Yes, indeed.

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

It definitely has.  In such a context, I'd suggest having a simple
shell sanity check that dies with this shell.