Merge branch 'canary' into chore/add-return-types

docs/api-reference/next/link.md

@@ -61,6 +61,7 @@ export default Home
 - [`replace`](#replace-the-url-instead-of-push) - Replace the current `history` state instead of adding a new url into the stack. Defaults to `false`
 - [`scroll`](#disable-scrolling-to-the-top-of-the-page) - Scroll to the top of the page after a navigation. Defaults to `true`
 - [`shallow`](/docs/routing/shallow-routing.md) - Update the path of the current page without rerunning [`getStaticProps`](/docs/basic-features/data-fetching.md#getstaticprops-static-generation), [`getServerSideProps`](/docs/basic-features/data-fetching.md#getserversideprops-server-side-rendering) or [`getInitialProps`](/docs/api-reference/data-fetching/getInitialProps.md). Defaults to `false`
+- `locale` - The active locale is automatically prepended. `locale` allows for providing a different locale. When `false` `href` has to include the locale as the default behavior is disabled.
 
 ## If the route has dynamic segments
 

packages/next/next-server/lib/head.tsx

@@ -62,8 +62,10 @@ function unique() {
 
   return (h: React.ReactElement<any>) => {
     let isUnique = true
+    let hasKey = false
 
     if (h.key && typeof h.key !== 'number' && h.key.indexOf('$') > 0) {
+      hasKey = true
       const key = h.key.slice(h.key.indexOf('$') + 1)
       if (keys.has(key)) {
         isUnique = false
@@ -96,7 +98,7 @@ function unique() {
           } else {
             const category = h.props[metatype]
             const categories = metaCategories[metatype] || new Set()
-            if (categories.has(category)) {
+            if ((metatype !== 'name' || !hasKey) && categories.has(category)) {
               isUnique = false
             } else {
               categories.add(category)

test/integration/client-navigation/pages/head.js

@@ -90,17 +90,28 @@ export default () => (
       <meta property="fb:pages" content="fbpages1" />
       <meta property="fb:pages" content="fbpages2" />
 
+      {/* both meta tags will be rendered since they use unique keys */}
+      <meta
+        name="citation_author"
+        content="authorName1"
+        key="citationAuthorTag1"
+      />
+      <meta
+        name="citation_author"
+        content="authorName2"
+        key="citationAuthorTag2"
+      />
+
       <React.Fragment>
         <title>Fragment title</title>
         <meta content="meta fragment" />
       </React.Fragment>
 
-      {/* the following 2 links tag will be rendered both */}
+      {/* the following 2 link tags will both be rendered */}
       <link rel="stylesheet" href="/dup-style.css" />
       <link rel="stylesheet" href="/dup-style.css" />
 
       {/* only one tag will be rendered as they have the same key */}
-
       <link rel="stylesheet" href="dedupe-style.css" key="my-style" />
       <link rel="stylesheet" href="dedupe-style.css" key="my-style" />
 

test/integration/client-navigation/test/rendering.js

@@ -170,6 +170,16 @@ export default function (render, fetch, ctx) {
       expect(html).toContain('<meta property="fb:pages" content="fbpages2"/>')
     })
 
+    test('header helper avoids dedupe of meta tags with the same name if they use unique keys', async () => {
+      const html = await render('/head')
+      expect(html).toContain(
+        '<meta name="citation_author" content="authorName1"/>'
+      )
+      expect(html).toContain(
+        '<meta name="citation_author" content="authorName2"/>'
+      )
+    })
+
     test('header helper renders Fragment children', async () => {
       const html = await render('/head')
       expect(html).toContain('<title>Fragment title</title>')