Merge "Assume relative links without / prefix are absolute"
diff --git a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.ts b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.ts
index e810637..516ee5f 100644
--- a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.ts
+++ b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text.ts
@@ -194,15 +194,25 @@
     // 4. Rewrite plain text ("text") to apply linking and other config-based
     //    rewrites. Text within code blocks is not passed here.
     // 5. Open links in a new tab by rendering with target="_blank" attribute.
+    // 6. Relative links without "/" prefix are assumed to be absolute links.
     function customRenderer(renderer: {[type: string]: Function}) {
-      renderer['link'] = (href: string, title: string, text: string) =>
+      renderer['link'] = (href: string, title: string, text: string) => {
+        if (
+          !href.startsWith('https://') &&
+          !href.startsWith('mailto:') &&
+          !href.startsWith('http://') &&
+          !href.startsWith('/')
+        ) {
+          href = `https://${href}`;
+        }
         /* HTML */
-        `<a
+        return `<a
           href="${href}"
           ${sameOrigin(href) ? '' : 'target="_blank" rel="noopener noreferrer"'}
           ${title ? `title="${title}"` : ''}
           >${text}</a
         >`;
+      };
       renderer['image'] = (href: string, _title: string, text: string) =>
         `![${text}](${href})`;
       renderer['codespan'] = (text: string) =>
diff --git a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_test.ts b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_test.ts
index a287659..23f1594 100644
--- a/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_test.ts
+++ b/polygerrit-ui/app/elements/shared/gr-formatted-text/gr-formatted-text_test.ts
@@ -510,6 +510,9 @@
       element.content = `[myLink1](https://www.google.com)
         [myLink2](/destiny)
         [myLink3](${origin}/destiny)
+        [myLink4](google.com)
+        [myLink5](http://google.com)
+        [myLink6](mailto:google@google.com)
       `;
       await element.updateComplete;
 
@@ -529,6 +532,27 @@
                 <a href="/destiny">myLink2</a>
                 <br />
                 <a href="${origin}/destiny">myLink3</a>
+                <br />
+                <a
+                  href="https://google.com"
+                  rel="noopener noreferrer"
+                  target="_blank"
+                  >myLink4</a
+                >
+                <br />
+                <a
+                  href="http://google.com"
+                  rel="noopener noreferrer"
+                  target="_blank"
+                  >myLink5</a
+                >
+                <br />
+                <a
+                  href="mailto:google@google.com"
+                  rel="noopener noreferrer"
+                  target="_blank"
+                  >myLink6</a
+                >
               </p>
             </div>
           </marked-element>