fix(VBreadcrumbs): v-for key error when two items have identical texts (

#6642)

* fix(VBreadcrumbs): v-for key error when two items have identical texts

closes #5454

* test(VBreadcrumbs): remove .only from test

packages/vuetify/src/components/VBreadcrumbs/VBreadcrumbs.ts

@@ -85,12 +85,15 @@ export default mixins(
     genItems () {
       const items = []
       const hasSlot = !!this.$scopedSlots.item
+      const keys = []
 
       for (let i = 0; i < this.items.length; i++) {
         const item = this.items[i]
 
+        keys.push(item.text)
+
         if (hasSlot) items.push(this.$scopedSlots.item!({ item }))
-        else items.push(this.$createElement(VBreadcrumbsItem, { key: item.text, props: item }, [item.text]))
+        else items.push(this.$createElement(VBreadcrumbsItem, { key: keys.join('.'), props: item }, [item.text]))
 
         if (i < this.items.length - 1) items.push(this.genDivider())
       }

packages/vuetify/test/unit/components/VBreadcrumbs/VBreadcrumbs.spec.js

@@ -37,6 +37,28 @@ test('VBreadcrumbs.js', ({ mount, compileToFunctions }) => {
     expect(wrapper.html()).toMatchSnapshot()
   })
 
+  it('should not complain about identical keys', () => {
+    const { render } = compileToFunctions(`
+      <v-breadcrumbs :items="items"></v-breadcrumbs>
+    `)
+
+    const component = Vue.component('test', {
+      components: {
+        VBreadcrumbs, VBreadcrumbsItem
+      },
+      data: () => ({
+        items: [
+          { text: 'a' },
+          { text: 'a' }
+        ]
+      }),
+      render
+    })
+    const wrapper = mount(component)
+
+    expect(`Duplicate keys detected: 'a'`).not.toHaveBeenWarned()
+  })
+
   it('should use slot to render items if present', () => {
     const { render } = compileToFunctions(`
       <v-breadcrumbs :items="items">