Use --single-branch

Handler/Shared.hs

@@ -221,6 +221,7 @@ rawClone tmpRepoDir repoCloningSpec chan = runWithChannel chan $ do
   let referenceBranch = repoSpecBranch $ cloningSpecReferenceRepo repoCloningSpec
   runProg Nothing gitPath ["clone",
                            "--progress",
+                           "--single-branch",
                            "--branch",
                            T.unpack referenceBranch,
                            T.unpack referenceUrl,

templates/challenge-how-to.hamlet

@@ -42,7 +42,7 @@ $case (appRepoScheme settings)
        \ (see <a href="@{YourAccountR}">your account</a>) if you want to have a repo hosted on Gonito.net, then:
 
   <pre>
-    git clone #{appRepoHost settings}#{shownId}/#{challengeName challenge}
+    git clone --single-branch #{appRepoHost settings}#{shownId}/#{challengeName challenge}
 
   <p>(Warning about empty repository is expected, don't worry about it.)
 
@@ -55,7 +55,7 @@ $case (appRepoScheme settings)
     <p>Clone the repo:
 
     <pre>
-      git clone #{repoUrl repo}
+      git clone --single-branch #{repoUrl repo}
 
     $maybe gitAnnexRemote <- (repoGitAnnexRemote repo)
       <pre>

templates/query-result.hamlet

@@ -6,5 +6,5 @@
 $if submissionIsPublic $ fsiSubmission submission
   <div .subm-repo>publicly available at: <code>#{publicSubmissionRepo}</code> / branch <code>#{publicSubmissionBranch}</code>
   <div .subm-browsable>browsable at: <a href="#{browsableUrl}">#{browsableUrl}</a>
-  <div .subm-clonable>to get it run: <code>git clone #{publicSubmissionRepo} -b #{publicSubmissionBranch}</code>
+  <div .subm-clonable>to get it run: <code>git clone --single-branch #{publicSubmissionRepo} -b #{publicSubmissionBranch}</code>
 <hr>