feat(errors): Catch normal and async errors in v-on handlers

Improves the check for promise-like objects to ensure they are thenable.
Includes tests.

src/core/util/error.js

@@ -24,9 +24,9 @@ export function handleError (err: Error, vm: any, info: string) {
   globalHandleError(err, vm, info)
 }
 
-export function handlePromiseError(value: any, vm: any, info: string) {
-  // if value is promise, handle it
-  if (value && typeof value.catch === 'function') {
+export function handlePromiseError (value: any, vm: any, info: string) {
+  // if value is promise, handle it (a promise must have a then function)
+  if (value && typeof value.then === 'function' && typeof value.catch === 'function') {
     value.catch(e => handleError(e, vm, info))
   }
 }

src/core/vdom/helpers/update-listeners.js

@@ -1,6 +1,6 @@
 /* @flow */
 
-import { warn } from 'core/util/index'
+import { warn, handleError, handlePromiseError } from 'core/util/index'
 import { cached, isUndef, isPlainObject } from 'shared/util'
 
 const normalizeEvent = cached((name: string): {
@@ -25,17 +25,29 @@ const normalizeEvent = cached((name: string): {
   }
 })
 
-export function createFnInvoker (fns: Function | Array<Function>): Function {
+export function createFnInvoker (fns: Function | Array<Function>, vm: ?Component): Function {
   function invoker () {
     const fns = invoker.fns
     if (Array.isArray(fns)) {
       const cloned = fns.slice()
       for (let i = 0; i < cloned.length; i++) {
-        cloned[i].apply(null, arguments)
+        try {
+          const result = cloned[i].apply(null, arguments)
+          handlePromiseError(result, vm, 'v-on async')
+        } catch (e) {
+          handleError(e, vm, 'v-on')
+        }
       }
     } else {
       // return handler return value for single handlers
-      return fns.apply(null, arguments)
+      let result
+      try {
+        result = fns.apply(null, arguments)
+        handlePromiseError(result, vm, 'v-on async')
+      } catch (e) {
+        handleError(e, vm, 'v-on')
+      }
+      return result
     }
   }
   invoker.fns = fns
@@ -66,7 +78,7 @@ export function updateListeners (
       )
     } else if (isUndef(old)) {
       if (isUndef(cur.fns)) {
-        cur = on[name] = createFnInvoker(cur)
+        cur = on[name] = createFnInvoker(cur, vm)
       }
       add(event.name, cur, event.once, event.capture, event.passive, event.params)
     } else if (cur !== old) {

test/unit/features/error-handling.spec.js

@@ -188,6 +188,35 @@ describe('Error handling', () => {
     expect(vm.$el.textContent).toContain('error in render')
     Vue.config.errorHandler = null
   })
+
+  it('should capture and recover from v-on errors', () => {
+    const spy = Vue.config.errorHandler = jasmine.createSpy('errorHandler')
+    const err1 = new Error('clickbork')
+    const vm = new Vue({
+      template: '<div v-on:click="bork"></div>',
+      methods: { bork: function () { throw err1 } }
+    }).$mount()
+    triggerEvent(vm.$el, 'click')
+    expect(spy.calls.count()).toBe(1)
+    expect(spy).toHaveBeenCalledWith(err1, vm, 'v-on')
+    Vue.config.errorHandler = null
+  })
+
+  it('should capture and recover from v-on async errors', (done) => {
+    const spy = Vue.config.errorHandler = jasmine.createSpy('errorHandler')
+    const err1 = new Error('clickbork')
+    const vm = new Vue({
+      template: '<div v-on:click="bork"></div>',
+      methods: { bork: function () { return new Promise(function (_resolve, reject) { reject(err1) }) } }
+    }).$mount()
+    triggerEvent(vm.$el, 'click')
+    Vue.nextTick(() => {
+      expect(spy.calls.count()).toBe(1)
+      expect(spy).toHaveBeenCalledWith(err1, vm, 'v-on async')
+      Vue.config.errorHandler = null
+      done()
+    })
+  })
 })
 
 function createErrorTestComponents () {