fix(v-model): add non-matching check back

change event should not be triggered if still can found
matching option for each value

Author: jkzing

src/platforms/web/runtime/directives/model.js

@@ -60,7 +60,14 @@ export default {
       const prevOptions = el._vOptions
       const curOptions = el._vOptions = [].map.call(el.options, getValue)
       if (curOptions.some((o, i) => !looseEqual(o, prevOptions[i]))) {
-        trigger(el, 'change')
+        // trigger change event if
+        // no matching option found for at least one value
+        const needReset = el.multiple
+          ? binding.value.some(v => hasNoMatchingOption(v, el.options))
+          : binding.value !== binding.oldValue && hasNoMatchingOption(binding.value, el.options)
+        if (needReset) {
+          trigger(el, 'change')
+        }
       }
     }
   }
@@ -101,6 +108,15 @@ function setSelected (el, binding, vm) {
   }
 }
 
+function hasNoMatchingOption (value, options) {
+  for (let i = 0, l = options.length; i < l; i++) {
+    if (looseEqual(getValue(options[i]), value)) {
+      return false
+    }
+  }
+  return true
+}
+
 function getValue (option) {
   return '_value' in option
     ? option._value

test/unit/features/directives/model-select.spec.js

@@ -519,7 +519,7 @@ describe('Directive v-model select', () => {
   })
 
   // #6193
-  it('should not trigger change event when match option can be found for each value', done => {
+  it('should not trigger change event when matching option can be found for each value', done => {
     const spy = jasmine.createSpy()
     const vm = new Vue({
       data: {