Ensuring that resetting to null does not cause an infinite loop. Fixes #512

Author: davidkpiano

src/reducers/form-actions-reducer.js

@@ -21,7 +21,7 @@ const resetFieldState = (field, key) => {
 
   if (field.$form) return mapValues(field, resetFieldState);
 
-  return i.merge(initialFieldState, {
+  return i.assign(initialFieldState, {
     value: field.initialValue,
     model: field.model,
     intents: [{ type: 'validate' }],

src/utils/update-field.js

@@ -4,6 +4,7 @@ import mapValues from './map-values';
 import { createInitialState } from '../reducers/form-reducer';
 
 function assocIn(state, path, value, fn) {
+  if (!path.length) return i.assign(state, value);
   if (!fn) return i.assocIn(state, path, value);
 
   const key0 = path[0];

test/form-reducer-actions-spec.js

@@ -697,4 +697,21 @@ describe('formReducer() (V1)', () => {
       assert.equal(resetState.foo.value, 'new initial');
     });
   });
+
+  describe('resetting to null', () => {
+    it('should work and not cause an infinite loop', () => {
+      assert.doesNotThrow(() => {
+        const reducer = formReducer('foo', null);
+
+        const state = reducer(
+           undefined,
+           actions.reset('foo')
+        );
+
+        assert.containSubset(state, {
+          value: null,
+        });
+      });
+    });
+  })
 });