fix(NgModelValidators): ensure all validators can properly toggle attribute values

Author: matsko

lib/directive/ng_model_validators.dart

@@ -132,8 +132,11 @@ class NgModelMaxNumberValidator implements NgValidator {
     try {
       num parsedValue = double.parse(value);
       _max = parsedValue.isNaN ? _max : parsedValue;
+    } catch(e) {
+      _max = null;
+    } finally {
       _ngModel.validateLater();
-    } catch(e) {};
+    }
   }
 
   bool isValid(modelValue) {
@@ -180,8 +183,11 @@ class NgModelMinNumberValidator implements NgValidator {
     try {
       num parsedValue = double.parse(value);
       _min = parsedValue.isNaN ? _min : parsedValue;
+    } catch(e) {
+      _min = null;
+    } finally {
       _ngModel.validateLater();
-    } catch(e) {};
+    }
   }
 
   bool isValid(modelValue) {

test/directive/ng_model_validators_spec.dart

@@ -595,6 +595,38 @@ void main() {
 
         expect(model.valid).toBe(true);
       });
+
+      it('ng-min', () {
+        var input = build('ng-min', 'number');
+        scope.apply(() {
+          scope.context['attr'] = '5.0';
+          scope.context['value'] = 3;
+        });
+
+        expect(model.valid).toBe(false);
+
+        scope.apply(() {
+          scope.context['attr'] = null;
+        });
+
+        expect(model.valid).toBe(true);
+      });
+
+      it('ng-max', () {
+        var input = build('ng-max', 'number');
+        scope.apply(() {
+          scope.context['attr'] = '5.0';
+          scope.context['value'] = 8;
+        });
+
+        expect(model.valid).toBe(false);
+
+        scope.apply(() {
+          scope.context['attr'] = null;
+        });
+
+        expect(model.valid).toBe(true);
+      });
     }); 
   });
 }