Handle selectors correctly in VersionedParams().

pkg/client/unversioned/request.go

@@ -427,8 +427,42 @@ func (r *Request) VersionedParams(obj runtime.Object, convertor runtime.ObjectCo
 		return r
 	}
 	for k, v := range params {
-		for _, vv := range v {
-			r.setParam(k, vv)
+		for _, value := range v {
+			// TODO: Move it to setParam method, once we get rid of
+			// FieldSelectorParam & LabelSelectorParam methods.
+			if k == unversioned.LabelSelectorQueryParam(r.apiVersion) && value == "" {
+				// Don't set an empty selector for backward compatibility.
+				// Since there is no way to get the difference between empty
+				// and unspecified string, we don't set it to avoid having
+				// labelSelector= param in every request.
+				continue
+			}
+			if k == unversioned.FieldSelectorQueryParam(r.apiVersion) {
+				if value == "" {
+					// Don't set an empty selector for backward compatibility.
+					// Since there is no way to get the difference between empty
+					// and unspecified string, we don't set it to avoid having
+					// fieldSelector= param in every request.
+					continue
+				}
+				// TODO: Filtering should be handled somewhere else.
+				selector, err := fields.ParseSelector(value)
+				if err != nil {
+					r.err = fmt.Errorf("unparsable field selector: %v", err)
+					return r
+				}
+				filteredSelector, err := selector.Transform(
+					func(field, value string) (newField, newValue string, err error) {
+						return fieldMappings.filterField(r.apiVersion, r.resource, field, value)
+					})
+				if err != nil {
+					r.err = fmt.Errorf("untransformable field selector: %v", err)
+					return r
+				}
+				value = filteredSelector.String()
+			}
+
+			r.setParam(k, value)
 		}
 	}
 	return r