From b52883cd5b20406fc2bd2f141fea1bb4e0bd2e5f Mon Sep 17 00:00:00 2001
From: Eduardo San Martin Morote <posva13@gmail.com>
Date: Tue, 17 Sep 2019 10:54:24 +0200
Subject: [PATCH 1/2] fix(props): correctly warn when a provided prop is Symbol

Fixes #10519
---
 src/core/util/props.js                   | 21 +++++++++++----------
 test/unit/features/options/props.spec.js | 10 ++++++++++
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/src/core/util/props.js b/src/core/util/props.js
index 1b57f77cdb5..aa69027efd0 100644
--- a/src/core/util/props.js
+++ b/src/core/util/props.js
@@ -205,18 +205,19 @@ function getInvalidTypeMessage (name, value, expectedTypes) {
     ` Expected ${expectedTypes.map(capitalize).join(', ')}`
   const expectedType = expectedTypes[0]
   const receivedType = toRawType(value)
-  const expectedValue = styleValue(value, expectedType)
-  const receivedValue = styleValue(value, receivedType)
   // check if we need to specify expected value
-  if (expectedTypes.length === 1 &&
-      isExplicable(expectedType) &&
-      !isBoolean(expectedType, receivedType)) {
-    message += ` with value ${expectedValue}`
+  if (
+    expectedTypes.length === 1 &&
+    isExplicable(expectedType) &&
+    isExplicable(typeof value) &&
+    !isBoolean(expectedType, receivedType)
+  ) {
+    message += ` with value ${styleValue(value, expectedType)}`
   }
   message += `, got ${receivedType} `
   // check if we need to specify received value
   if (isExplicable(receivedType)) {
-    message += `with value ${receivedValue}.`
+    message += `with value ${styleValue(value, receivedType)}.`
   }
   return message
 }
@@ -231,9 +232,9 @@ function styleValue (value, type) {
   }
 }
 
-function isExplicable (value) {
-  const explicitTypes = ['string', 'number', 'boolean']
-  return explicitTypes.some(elem => value.toLowerCase() === elem)
+const EXPLICABLE_TYPES = ['string', 'number', 'boolean']
+function isExplicable(value) {
+  return EXPLICABLE_TYPES.some(elem => value.toLowerCase() === elem)
 }
 
 function isBoolean (...args) {
diff --git a/test/unit/features/options/props.spec.js b/test/unit/features/options/props.spec.js
index 5adedeb2e6e..b2bf482737b 100644
--- a/test/unit/features/options/props.spec.js
+++ b/test/unit/features/options/props.spec.js
@@ -241,6 +241,16 @@ describe('Options props', () => {
         makeInstance({}, Symbol)
         expect('Expected Symbol, got Object').toHaveBeenWarned()
       })
+
+      it('warns when expected an explicable type but Symbol was provided', () => {
+        makeInstance(Symbol('foo'), String)
+        expect('Expected String, got Symbol').toHaveBeenWarned()
+      })
+
+      it('warns when expected an explicable type but Symbol was provided', () => {
+        makeInstance(Symbol('foo'), [String, Number])
+        expect('Expected String, Number, got Symbol').toHaveBeenWarned()
+      })
     }
 
     it('custom constructor', () => {

From 3d1c8f5c93b26546601b0992996eaa5021d9867b Mon Sep 17 00:00:00 2001
From: Eduardo San Martin Morote <posva13@gmail.com>
Date: Tue, 17 Sep 2019 10:56:27 +0200
Subject: [PATCH 2/2] style: space before parens

---
 src/core/util/props.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/util/props.js b/src/core/util/props.js
index aa69027efd0..26a76664ccc 100644
--- a/src/core/util/props.js
+++ b/src/core/util/props.js
@@ -233,7 +233,7 @@ function styleValue (value, type) {
 }
 
 const EXPLICABLE_TYPES = ['string', 'number', 'boolean']
-function isExplicable(value) {
+function isExplicable (value) {
   return EXPLICABLE_TYPES.some(elem => value.toLowerCase() === elem)
 }