* doc/autoconf.texi (Shell Substitutions): Warn about unbalanced

parentheses in $(...).  Problem reported by Eric Blake.

diff --git a/ChangeLog b/ChangeLog
index f57d73d1148d9517197194c63ae7014657628433..c42821289b10ff907b0799b40118dbb7b3e27549 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2005-12-29  Paul Eggert  <eggert@cs.ucla.edu>
+
+       * doc/autoconf.texi (Shell Substitutions): Warn about unbalanced
+       parentheses in $(...).  Problem reported by Eric Blake.
+
 2005-12-12  Paul Eggert  <eggert@cs.ucla.edu>
 
        * doc/autoconf.texi (Limitations of Usual Tools):

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 290d614412326b7b096f0e96dff921778f026121..5abb66dd59ccff4d8eaf3211bf1faf2d06d83953 100644 (file)
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -10511,6 +10511,15 @@ a different notation @samp{$((@var{expression}))} that in modern
 shells is an arithmetic expression not a command.  To avoid the
 confusion, insert a space between the two opening parentheses.
 
+Avoid @var{commands} that contain unbalanced parentheses in
+here-documents, comments, or case statement patterns, as many shells
+mishandle them.  For example, Bash 3.1, @samp{ksh88}, @command{pdksh}
+5.2.14, and Zsh 4.2.6 all mishandle the following valid command:
+
+@example
+echo $(case x in x) echo hello;; esac)
+@end example
+
 @end table