From 7a0bb19d072b65451ba4fff8c19587cbcce95598 Mon Sep 17 00:00:00 2001
From: Alex <stukak@gmail.com>
Date: Fri, 9 Mar 2018 00:09:53 +0200
Subject: [PATCH] fix(v-on): return handler value when using modifiers (#7704)

---
 src/compiler/codegen/events.js                |  4 +-
 test/unit/modules/compiler/codegen.spec.js    | 91 ++++++++++++++-----
 .../modules/vdom/patch/edge-cases.spec.js     | 37 ++++++++
 3 files changed, 107 insertions(+), 25 deletions(-)

diff --git a/src/compiler/codegen/events.js b/src/compiler/codegen/events.js
index 084c2908dcf..58e7b014760 100644
--- a/src/compiler/codegen/events.js
+++ b/src/compiler/codegen/events.js
@@ -132,9 +132,9 @@ function genHandler (
       code += genModifierCode
     }
     const handlerCode = isMethodPath
-      ? handler.value + '($event)'
+      ? `return ${handler.value}($event)`
       : isFunctionExpression
-        ? `(${handler.value})($event)`
+        ? `return (${handler.value})($event)`
         : handler.value
     /* istanbul ignore if */
     if (__WEEX__ && handler.params) {
diff --git a/test/unit/modules/compiler/codegen.spec.js b/test/unit/modules/compiler/codegen.spec.js
index a072904ece0..93a27f3b245 100644
--- a/test/unit/modules/compiler/codegen.spec.js
+++ b/test/unit/modules/compiler/codegen.spec.js
@@ -269,45 +269,90 @@ describe('codegen', () => {
     )
   })
 
+  it('generate events with method call', () => {
+    assertCodegen(
+      '<input @input="onInput($event);">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput($event);}}})}`
+    )
+    // empty arguments
+    assertCodegen(
+      '<input @input="onInput();">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput();}}})}`
+    )
+    // without semicolon
+    assertCodegen(
+      '<input @input="onInput($event)">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput($event)}}})}`
+    )
+    // multiple args
+    assertCodegen(
+      '<input @input="onInput($event, \'abc\', 5);">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput($event, 'abc', 5);}}})}`
+    )
+    // expression in args
+    assertCodegen(
+      '<input @input="onInput($event, 2+2);">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput($event, 2+2);}}})}`
+    )
+    // tricky symbols in args
+    assertCodegen(
+      '<input @input="onInput(\');[\'());\');">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput(');[\'());');}}})}`
+    )
+  })
+
+  it('generate events with multiple statements', () => {
+    // normal function
+    assertCodegen(
+      '<input @input="onInput1();onInput2()">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput1();onInput2()}}})}`
+    )
+    // function with multiple args
+    assertCodegen(
+      '<input @input="onInput1($event, \'text\');onInput2(\'text2\', $event)">',
+      `with(this){return _c('input',{on:{"input":function($event){onInput1($event, 'text');onInput2('text2', $event)}}})}`
+    )
+  })
+
   it('generate events with keycode', () => {
     assertCodegen(
       '<input @input.enter="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;return onInput($event)}}})}`
     )
     // multiple keycodes (delete)
     assertCodegen(
       '<input @input.delete="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&_k($event.keyCode,"delete",[8,46],$event.key,["Backspace","Delete"]))return null;onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&_k($event.keyCode,"delete",[8,46],$event.key,["Backspace","Delete"]))return null;return onInput($event)}}})}`
     )
     // multiple keycodes (chained)
     assertCodegen(
       '<input @keydown.enter.delete="onInput">',
-      `with(this){return _c('input',{on:{"keydown":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter")&&_k($event.keyCode,"delete",[8,46],$event.key,["Backspace","Delete"]))return null;onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"keydown":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter")&&_k($event.keyCode,"delete",[8,46],$event.key,["Backspace","Delete"]))return null;return onInput($event)}}})}`
     )
     // number keycode
     assertCodegen(
       '<input @input.13="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&$event.keyCode!==13)return null;onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&$event.keyCode!==13)return null;return onInput($event)}}})}`
     )
     // custom keycode
     assertCodegen(
       '<input @input.custom="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&_k($event.keyCode,"custom",undefined,$event.key,undefined))return null;onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){if(!('button' in $event)&&_k($event.keyCode,"custom",undefined,$event.key,undefined))return null;return onInput($event)}}})}`
     )
   })
 
   it('generate events with generic modifiers', () => {
     assertCodegen(
       '<input @input.stop="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){$event.stopPropagation();onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){$event.stopPropagation();return onInput($event)}}})}`
     )
     assertCodegen(
       '<input @input.prevent="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){$event.preventDefault();onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){$event.preventDefault();return onInput($event)}}})}`
     )
     assertCodegen(
       '<input @input.self="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){if($event.target !== $event.currentTarget)return null;onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){if($event.target !== $event.currentTarget)return null;return onInput($event)}}})}`
     )
   })
 
@@ -315,74 +360,74 @@ describe('codegen', () => {
   it('generate events with generic modifiers and keycode correct order', () => {
     assertCodegen(
       '<input @keydown.enter.prevent="onInput">',
-      `with(this){return _c('input',{on:{"keydown":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;$event.preventDefault();onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"keydown":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;$event.preventDefault();return onInput($event)}}})}`
     )
 
     assertCodegen(
       '<input @keydown.enter.stop="onInput">',
-      `with(this){return _c('input',{on:{"keydown":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;$event.stopPropagation();onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"keydown":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;$event.stopPropagation();return onInput($event)}}})}`
     )
   })
 
   it('generate events with mouse event modifiers', () => {
     assertCodegen(
       '<input @click.ctrl="onClick">',
-      `with(this){return _c('input',{on:{"click":function($event){if(!$event.ctrlKey)return null;onClick($event)}}})}`
+      `with(this){return _c('input',{on:{"click":function($event){if(!$event.ctrlKey)return null;return onClick($event)}}})}`
     )
     assertCodegen(
       '<input @click.shift="onClick">',
-      `with(this){return _c('input',{on:{"click":function($event){if(!$event.shiftKey)return null;onClick($event)}}})}`
+      `with(this){return _c('input',{on:{"click":function($event){if(!$event.shiftKey)return null;return onClick($event)}}})}`
     )
     assertCodegen(
       '<input @click.alt="onClick">',
-      `with(this){return _c('input',{on:{"click":function($event){if(!$event.altKey)return null;onClick($event)}}})}`
+      `with(this){return _c('input',{on:{"click":function($event){if(!$event.altKey)return null;return onClick($event)}}})}`
     )
     assertCodegen(
       '<input @click.meta="onClick">',
-      `with(this){return _c('input',{on:{"click":function($event){if(!$event.metaKey)return null;onClick($event)}}})}`
+      `with(this){return _c('input',{on:{"click":function($event){if(!$event.metaKey)return null;return onClick($event)}}})}`
     )
     assertCodegen(
       '<input @click.exact="onClick">',
-      `with(this){return _c('input',{on:{"click":function($event){if($event.ctrlKey||$event.shiftKey||$event.altKey||$event.metaKey)return null;onClick($event)}}})}`
+      `with(this){return _c('input',{on:{"click":function($event){if($event.ctrlKey||$event.shiftKey||$event.altKey||$event.metaKey)return null;return onClick($event)}}})}`
     )
     assertCodegen(
       '<input @click.ctrl.exact="onClick">',
-      `with(this){return _c('input',{on:{"click":function($event){if(!$event.ctrlKey)return null;if($event.shiftKey||$event.altKey||$event.metaKey)return null;onClick($event)}}})}`
+      `with(this){return _c('input',{on:{"click":function($event){if(!$event.ctrlKey)return null;if($event.shiftKey||$event.altKey||$event.metaKey)return null;return onClick($event)}}})}`
     )
   })
 
   it('generate events with multiple modifiers', () => {
     assertCodegen(
       '<input @input.stop.prevent.self="onInput">',
-      `with(this){return _c('input',{on:{"input":function($event){$event.stopPropagation();$event.preventDefault();if($event.target !== $event.currentTarget)return null;onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"input":function($event){$event.stopPropagation();$event.preventDefault();if($event.target !== $event.currentTarget)return null;return onInput($event)}}})}`
     )
   })
 
   it('generate events with capture modifier', () => {
     assertCodegen(
       '<input @input.capture="onInput">',
-      `with(this){return _c('input',{on:{"!input":function($event){onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"!input":function($event){return onInput($event)}}})}`
     )
   })
 
   it('generate events with once modifier', () => {
     assertCodegen(
       '<input @input.once="onInput">',
-      `with(this){return _c('input',{on:{"~input":function($event){onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"~input":function($event){return onInput($event)}}})}`
     )
   })
 
   it('generate events with capture and once modifier', () => {
     assertCodegen(
       '<input @input.capture.once="onInput">',
-      `with(this){return _c('input',{on:{"~!input":function($event){onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"~!input":function($event){return onInput($event)}}})}`
     )
   })
 
   it('generate events with once and capture modifier', () => {
     assertCodegen(
       '<input @input.once.capture="onInput">',
-      `with(this){return _c('input',{on:{"~!input":function($event){onInput($event)}}})}`
+      `with(this){return _c('input',{on:{"~!input":function($event){return onInput($event)}}})}`
     )
   })
 
@@ -427,7 +472,7 @@ describe('codegen', () => {
     // with modifiers
     assertCodegen(
       `<input @keyup.enter="e=>current++">`,
-      `with(this){return _c('input',{on:{"keyup":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;(e=>current++)($event)}}})}`
+      `with(this){return _c('input',{on:{"keyup":function($event){if(!('button' in $event)&&_k($event.keyCode,"enter",13,$event.key,"Enter"))return null;return (e=>current++)($event)}}})}`
     )
   })
 
@@ -452,7 +497,7 @@ describe('codegen', () => {
   it('generate multiple event handlers', () => {
     assertCodegen(
       '<input @input="current++" @input.stop="onInput">',
-      `with(this){return _c('input',{on:{"input":[function($event){current++},function($event){$event.stopPropagation();onInput($event)}]}})}`
+      `with(this){return _c('input',{on:{"input":[function($event){current++},function($event){$event.stopPropagation();return onInput($event)}]}})}`
     )
   })
 
diff --git a/test/unit/modules/vdom/patch/edge-cases.spec.js b/test/unit/modules/vdom/patch/edge-cases.spec.js
index 8d07f76dc33..adcfc95eedc 100644
--- a/test/unit/modules/vdom/patch/edge-cases.spec.js
+++ b/test/unit/modules/vdom/patch/edge-cases.spec.js
@@ -25,6 +25,43 @@ describe('vdom patch: edge cases', () => {
     }).then(done)
   })
 
+  // exposed by #7705
+  // methods and function expressions with modifiers should return result instead of undefined
+  // skipped odd children[1,3, ...] because they are rendered as text nodes with undefined value
+  it('should return listener\'s result for method name and function expression with and w/o modifiers', done => {
+    const dummyEvt = { preventDefault: () => {} }
+    new Vue({
+      template: `
+        <div v-test>
+          <div @click="addFive"></div>
+          <div @click.prevent="addFive"></div>
+          <div @click="addFive($event, 5)"></div>
+          <div @click.prevent="addFive($event, 5)"></div>
+        </div>
+      `,
+      methods: {
+        addFive ($event, toAdd = 0) {
+          return toAdd + 5
+        }
+      },
+      directives: {
+        test: {
+          bind (el, binding, vnode) {
+            waitForUpdate(() => {
+              expect(vnode.children[0].data.on.click()).toBe(5)
+            }).then(() => {
+              expect(vnode.children[2].data.on.click(dummyEvt)).toBe(5)
+            }).then(() => {
+              expect(vnode.children[4].data.on.click()).not.toBeDefined()
+            }).then(() => {
+              expect(vnode.children[6].data.on.click(dummyEvt)).not.toBeDefined()
+            }).then(done)
+          }
+        }
+      }
+    }).$mount()
+  })
+
   // #3533
   // a static node is reused in createElm, which changes its elm reference
   // and is inserted into a different parent.