From aca2c2a81e2793befce516378a02afd1e4da3d3d Mon Sep 17 00:00:00 2001
From: Ruijia Tang <413732712@qq.com>
Date: Mon, 20 Jan 2020 23:15:53 +0800
Subject: [PATCH] fix(compiler-core): avoid override user keys when injecting
 branch key (#630)

---
 .../transforms/__snapshots__/vIf.spec.ts.snap      | 14 ++++++++++++++
 .../compiler-core/__tests__/transforms/vIf.spec.ts | 14 ++++++++++++++
 packages/compiler-core/src/utils.ts                | 13 ++++++++++++-
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/packages/compiler-core/__tests__/transforms/__snapshots__/vIf.spec.ts.snap b/packages/compiler-core/__tests__/transforms/__snapshots__/vIf.spec.ts.snap
index 498c03d35c6..d647b073453 100644
--- a/packages/compiler-core/__tests__/transforms/__snapshots__/vIf.spec.ts.snap
+++ b/packages/compiler-core/__tests__/transforms/__snapshots__/vIf.spec.ts.snap
@@ -105,3 +105,17 @@ return function render() {
   }
 }"
 `;
+
+exports[`compiler: v-if codegen v-if with key 1`] = `
+"const _Vue = Vue
+
+return function render() {
+  with (this) {
+    const { openBlock: _openBlock, createVNode: _createVNode, createBlock: _createBlock, createCommentVNode: _createCommentVNode } = _Vue
+    
+    return (_openBlock(), ok
+      ? _createBlock(\\"div\\", { key: \\"some-key\\" })
+      : _createCommentVNode(\\"v-if\\", true))
+  }
+}"
+`;
diff --git a/packages/compiler-core/__tests__/transforms/vIf.spec.ts b/packages/compiler-core/__tests__/transforms/vIf.spec.ts
index f50ad66297d..b6c2e86a28c 100644
--- a/packages/compiler-core/__tests__/transforms/vIf.spec.ts
+++ b/packages/compiler-core/__tests__/transforms/vIf.spec.ts
@@ -530,6 +530,20 @@ describe('compiler: v-if', () => {
       )
     })
 
+    test('v-if with key', () => {
+      const {
+        root,
+        node: { codegenNode }
+      } = parseWithIfTransform(`<div v-if="ok" key="some-key"/>`)
+      const branch1 = (codegenNode.expressions[1] as ConditionalExpression)
+        .consequent as CallExpression
+      expect(branch1.arguments).toMatchObject([
+        `"div"`,
+        createObjectMatcher({ key: 'some-key' })
+      ])
+      expect(generate(root).code).toMatchSnapshot()
+    })
+
     test.todo('with comments')
   })
 })
diff --git a/packages/compiler-core/src/utils.ts b/packages/compiler-core/src/utils.ts
index 3060c1c1095..280e9c5e2dc 100644
--- a/packages/compiler-core/src/utils.ts
+++ b/packages/compiler-core/src/utils.ts
@@ -253,7 +253,18 @@ export function injectProp(
     }
     propsWithInjection = props
   } else if (props.type === NodeTypes.JS_OBJECT_EXPRESSION) {
-    props.properties.unshift(prop)
+    let alreadyExists = false
+    // check existing key to avoid overriding user provided keys
+    if (prop.key.type === NodeTypes.SIMPLE_EXPRESSION) {
+      const propKeyName = prop.key.content
+      alreadyExists = props.properties.some(p => (
+        p.key.type === NodeTypes.SIMPLE_EXPRESSION &&
+        p.key.content === propKeyName
+      ))
+    }
+    if (!alreadyExists) {
+      props.properties.unshift(prop)
+    }
     propsWithInjection = props
   } else {
     // single v-bind with expression, return a merged replacement