Merge pull request #1549 from NixOS/feat/github-diffs

feat: Offload git diffs to GitHub

src/root/common.tt

@@ -347,6 +347,15 @@ BLOCK renderDiffUri;
     url = res.0;
     branch = res.1;
     IF bi1.type == "hg" || bi1.type == "git" %]
+      [% IF url.substr(0, 19) == "https://github.com/" %]
+        <a target="_blank" [% HTML.attributes(href =>
+          url
+          _ "/compare/"
+          _ bi1.revision
+          _ "..."
+          _ bi2.revision,
+        ) %]>[% HTML.escape(contents) %]</a>
+      [% ELSE %]
         <a target="_blank" [% HTML.attributes(href => c.uri_for('/api/scmdiff', {
           uri = url,
           rev1 = bi1.revision,
@@ -354,6 +363,7 @@ BLOCK renderDiffUri;
           type = bi1.type,
           branch = branch
         })) %]>[% HTML.escape(contents) %]</a>
+      [% END %]
     [% ELSE;
       contents;
     END;