29703: crash when failing to parse process substitutions

ChangeLog

@@ -1,5 +1,7 @@
 2011-08-17  Peter Stephenson  <p.w.stephenson@ntlworld.com>
 
+	* 29703: Src/exec.c, Src/subst.c, Test/D03procsubst.ztst: 
+
 	* users/16253, users/16255: Src/utils.c, Test/D04parameter.ztst:
         A nulstring should be split like an empty string.
 
@@ -15297,5 +15299,5 @@
 
 *****************************************************
 * This is used by the shell to define $ZSH_PATCHLEVEL
-* $Revision: 1.5438 $
+* $Revision: 1.5439 $
 *****************************************************

Src/exec.c

@@ -3755,7 +3755,15 @@ parsecmd(char *cmd, char **eptr)
 
     for (str = cmd + 2; *str && *str != Outpar; str++);
     if (!*str || cmd[1] != Inpar) {
-	zerr("oops.");
+	/*
+	 * This can happen if the expression is being parsed
+	 * inside another construct, e.g. as a value within ${..:..} etc.
+	 * So print a proper error message instead of the not very
+	 * useful but traditional "oops".
+ 	 */
+	char *errstr = dupstrpfx(cmd, 2);
+	untokenize(errstr);
+	zerr("unterminated `%s...)'", errstr);
 	return NULL;
     }
     *str = '\0';

Src/subst.c

@@ -162,6 +162,8 @@ stringsubst(LinkList list, LinkNode node, int ssub, int asssub)
 		subst = getproc(str, &rest);	/* <(...) or >(...) */
 	    else
 		subst = getoutputfile(str, &rest);	/* =(...) */
+	    if (errflag)
+		return NULL;
 	    if (!subst)
 		subst = "";
 

Test/D03procsubst.ztst

@@ -84,3 +84,7 @@
   )
 0:=(...) preceded by other stuff has no special effect
 >everything,=(here is left),alone
+
+  print something=${:-=(echo 'C,D),(F,G)'}
+1: Graceful handling of bad substitution in enclosed context
+?(eval):1: unterminated `=(...)'