From 3937fc9c265632810745124a6943f5e98d5da4e6 Mon Sep 17 00:00:00 2001
From: Jilles Tjoelker <jilles@FreeBSD.org>
Date: Wed, 4 May 2011 22:12:22 +0000
Subject: [PATCH] sh: Apply set -u to variables in arithmetic.

Note that this only applies to variables that are actually used.
Things like (0 && unsetvar) do not cause an error.

Exp-run done by: pav (with some other sh(1) changes)
---
 bin/sh/arith_yacc.c                        | 2 ++
 tools/regression/bin/sh/expansion/set-u3.0 | 6 ++++++
 2 files changed, 8 insertions(+)
 create mode 100644 tools/regression/bin/sh/expansion/set-u3.0

diff --git a/bin/sh/arith_yacc.c b/bin/sh/arith_yacc.c
index edb321ff05f..63f236c5611 100644
--- a/bin/sh/arith_yacc.c
+++ b/bin/sh/arith_yacc.c
@@ -97,6 +97,8 @@ static arith_t arith_lookupvarint(char *varname)
 	arith_t result;
 
 	str = lookupvar(varname);
+	if (uflag && str == NULL)
+		yyerror("variable not set");
 	if (str == NULL || *str == '\0')
 		str = "0";
 	errno = 0;
diff --git a/tools/regression/bin/sh/expansion/set-u3.0 b/tools/regression/bin/sh/expansion/set-u3.0
new file mode 100644
index 00000000000..7f199b42c79
--- /dev/null
+++ b/tools/regression/bin/sh/expansion/set-u3.0
@@ -0,0 +1,6 @@
+# $FreeBSD$
+
+set -u
+unset x
+v=$( (eval ': $((x))') 2>&1 >/dev/null)
+[ $? -ne 0 ] && [ -n "$v" ]