ast/ConfHandler: Add a syntax to clear variable

unset VAR
will clear variable VAR
unset VAR[flag]
will clear flag "flag" from var VAR

Signed-off-by: Jérémy Rosen <jeremy.rosen@openwide.fr>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/bb/tests/parse.py b/lib/bb/tests/parse.py
index c296db201..0b2706af0 100644
--- a/lib/bb/tests/parse.py
+++ b/lib/bb/tests/parse.py
@@ -68,6 +68,23 @@ C = "3"
         with self.assertRaises(bb.parse.ParseError):
             d = bb.parse.handle(f.name, self.d)['']
 
+    unsettest = """
+A = "1"
+B = "2"
+B[flag] = "3"
+
+unset A
+unset B[flag]
+"""
+
+    def test_parse_unset(self):
+        f = self.parsehelper(self.unsettest)
+        d = bb.parse.handle(f.name, self.d)['']
+        self.assertEqual(d.getVar("A", True), None)
+        self.assertEqual(d.getVarFlag("A","flag", True), None)
+        self.assertEqual(d.getVar("B", True), "2")
+        
+
     overridetest = """
 RRECOMMENDS_${PN} = "a"
 RRECOMMENDS_${PN}_libc = "b"