24150: Exit status of null command should be exit status of last cmdsubst.

ChangeLog

@@ -1,6 +1,14 @@
+2007-12-09  Barton E. Schaefer  <schaefer@zsh.org>
+
+	* 24150 plus unposted: Src/exec.c, Test/D08cmdsubst.ztst:
+	Retain exit status of last non-assignment command substitution
+	across variable assignment processing so that, in the event of
+	no command word to execute, the exit status of the statement is
+	that of the last command substitution (per POSIX).
+
 2007-12-09  Peter Stephenson  <p.w.stephenson@ntlworld.com>
 
-	* 24197, Src/utils.c, Src/Modules/datetime.c: interface to
+	* 24197: Src/utils.c, Src/Modules/datetime.c: interface to
 	ztrftime() for insufficient memory was broken.
 
 2007-12-08  Clint Adams  <clint@zsh.org>

Src/exec.c

@@ -2339,7 +2339,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		    lastval = 0;
 		    return;
 		} else {
-		    cmdoutval = 0;
+		    cmdoutval = lastval;
 		    if (varspc)
 			addvars(state, varspc, 0);
 		    if (errflag)

Test/D08cmdsubst.ztst

@@ -81,3 +81,11 @@