helper/schema: can set Partial(true) multiple times

helper/schema/resource_data.go

@@ -114,13 +114,12 @@ func (d *ResourceData) HasChange(key string) bool {
 // When partial state mode is enabled, then only key prefixes specified
 // by SetPartial will be in the final state. This allows providers to return
 // partial states for partially applied resources (when errors occur).
-//
-// When partial state mode is toggled, the map of enabled partial states
-// (by SetPartial) is reset.
 func (d *ResourceData) Partial(on bool) {
 	d.partial = on
 	if on {
-		d.partialMap = make(map[string]struct{})
+		if d.partialMap == nil {
+			d.partialMap = make(map[string]struct{})
+		}
 	} else {
 		d.partialMap = nil
 	}