Don't allow MapMutation.update() calls after the mutation is finished

2 files changed, 7 insertions, 0 deletions

diff --git a/immutables/_map.c b/immutables/_map.c
index 9a81556..9b406ea 100644
--- a/immutables/_map.c
+++ b/immutables/_map.c
@@ -3880,6 +3880,10 @@ mapmut_py_update(MapMutationObject *self, PyObject *args, PyObject *kwds)
         return NULL;
     }
 
+    if (mapmut_check_finalized(self)) {
+        return NULL;
+    }
+
     if (arg != NULL) {
         if (map_update_inplace(self->m_mutid, (BaseMapObject *)self, arg)) {
             return NULL;
diff --git a/immutables/map.py b/immutables/map.py
index 7b230dd..4c5cd49 100644
--- a/immutables/map.py
+++ b/immutables/map.py
@@ -719,6 +719,9 @@ class MapMutation:
             return True
 
     def update(self, col=None, **kw):
+        if self.__mutid == 0:
+            raise ValueError('mutation {!r} has been finished'.format(self))
+
         it = None
         if col is not None:
             if hasattr(col, 'items'):