Add check for empty origin special case (#608)

* Add check for empty origin special case

* add doc link

util/gnmi.go

@@ -103,7 +103,11 @@ func PathMatchesPathElemPrefix(path, prefix *gpb.Path) bool {
 // If either path and query contain nil elements func returns false.
 // Both paths must use the gNMI >=0.4.0 PathElem path format.
 func PathMatchesQuery(path, query *gpb.Path) bool {
-	if len(path.GetElem()) < len(query.GetElem()) || path.Origin != query.Origin {
+	if len(path.GetElem()) < len(query.GetElem()) {
+		return false
+	}
+	// Unset Origin fields can match "openconfig", see https://github.com/openconfig/reference/blob/master/rpc/gnmi/mixed-schema.md#special-values-of-origin.
+	if path.Origin != query.Origin && !(path.Origin == "" && query.Origin == "openconfig" || path.Origin == "openconfig" && query.Origin == "") {
 		return false
 	}
 	for i, queryElem := range query.Elem {

util/gnmi_test.go

@@ -547,6 +547,24 @@ func TestPathMatchesQuery(t *testing.T) {
 			}},
 		},
 		want: true,
+	}, {
+		desc: "valid query with implied openconfig origin path",
+		inPath: &gpb.Path{
+			Origin: "",
+		},
+		inQuery: &gpb.Path{
+			Origin: "openconfig",
+		},
+		want: true,
+	}, {
+		desc: "valid query with implied openconfig origin query",
+		inPath: &gpb.Path{
+			Origin: "openconfig",
+		},
+		inQuery: &gpb.Path{
+			Origin: "",
+		},
+		want: true,
 	}, {
 		desc: "valid query with wildcard name",
 		inPath: &gpb.Path{
@@ -648,6 +666,21 @@ func TestPathMatchesQuery(t *testing.T) {
 				Name: "three",
 			}},
 		},
+	}, {
+		desc: "invalid longer query",
+		inPath: &gpb.Path{
+			Elem: []*gpb.PathElem{
+				{
+					Name: "twelve",
+				}},
+		},
+		inQuery: &gpb.Path{
+			Elem: []*gpb.PathElem{{
+				Name: "one",
+			}, {
+				Name: "two",
+			}},
+		},
 	}, {
 		desc: "invalid names not equal",
 		inPath: &gpb.Path{