FYI: foo=${foo='}'}

[Akim Demaille]

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * doc/autoconf.texi (Shell Substitutions): Some information about
        Solaris' sh handling of ``foo=${foo='}'}'' collected by Alexandre,
        reported by David Taylor.

2000-11-10  Akim Demaille  <address@hidden>

Index: doc/autoconf.texi
===================================================================
RCS file: /cvs/autoconf/doc/autoconf.texi,v
retrieving revision 1.379
diff -u -u -r1.379 autoconf.texi
--- doc/autoconf.texi 2000/11/10 14:44:30 1.379
+++ doc/autoconf.texi 2000/11/10 14:54:35
@@ -5150,6 +5150,33 @@
 Old @sc{bsd} shells, including the Ultrix @code{sh}, don't accept the
 colon for any shell substitution, and complain and die.
 
address@hidden address@hidden@var{var}='@var{value}'@}
address@hidden address@hidden@var{var}='@var{value}'@}
+Solaris' @command{/bin/sh} has a frightening bug in its understanding
+this.  Imagine you need set a variable to a string containing @address@hidden
+This @address@hidden character got Solaris' @command{/bin/sh} confused when
+the affected variable was already set.  This bug can be exercised by
+running:
+
address@hidden
+% /bin/sh
+$ unset foo
+$ address@hidden'@}'@}
+$ echo $foo
address@hidden
+$ address@hidden'@}'   # no error; this hints to what the bug is
+$ echo $foo
address@hidden
+$ address@hidden'@}'@}
+$ echo $foo
address@hidden@}
+ ^ ugh!
address@hidden example
+
+It seems that @address@hidden is considered to match @address@hidden, even 
though
+it is enclosed in single quotes.  The problem doesn't happen using
+double quotes.
+
 @item $(@var{commands})
 @cindex $(@var{commands})
 This construct is meant to replace @address@hidden; they can be