Fixed url generated by pull request/compare button

The `:` character was getting escaped leading to an ugly url. This is
different from the urls generated when editing the branches in a pull
request. In that case the url did not have `:` escaped.

src/main/scala/gitbucket/core/view/helpers.scala

@@ -160,6 +160,12 @@ object helpers extends AvatarImageProvider with LinkConverter with RequestCache
    */
   def encodeRefName(value: String): String = StringUtil.urlEncode(value).replace("%2F", "/")
 
+  /**
+   * Url encode except '/' and ':'
+   */
+  def encodeCompareBranch(value: String) =
+    StringUtil.urlEncode(value).replace("%2F", "/").replace("%3A", ":")
+
   def urlEncode(value: String): String = StringUtil.urlEncode(value)
 
   def urlEncode(value: Option[String]): String = value.map(urlEncode).getOrElse("")

src/main/twirl/gitbucket/core/repo/branches.scala.html

@@ -30,9 +30,9 @@
                   }
                 }.getOrElse{
                   @if(context.loginAccount.isDefined){
-                    <a href="@url(repository)/compare/@{encodeRefName(repositoryDefaultCompareOrigin(repository.repository))}...@{encodeRefName(branch.name)}?expand=1" class="btn btn-small">New Pull Request</a>
+                    <a href="@url(repository)/compare/@{encodeCompareBranch(repositoryDefaultCompareOrigin(repository.repository))}...@{encodeCompareBranch(branch.name)}?expand=1" class="btn btn-small">New Pull Request</a>
                   }else{
-                    <a href="@url(repository)/compare/@{encodeRefName(repositoryDefaultCompareOrigin(repository.repository))}...@{encodeRefName(branch.name)}" class="btn btn-small">Compare</a>
+                    <a href="@url(repository)/compare/@{encodeCompareBranch(repositoryDefaultCompareOrigin(repository.repository))}...@{encodeCompareBranch(branch.name)}" class="btn btn-small">Compare</a>
                   }
                 }
                 @if(hasWritePermission){

src/test/scala/gitbucket/core/view/HelpersSpec.scala

@@ -34,4 +34,18 @@ class HelpersSpec extends Specification {
       helpers.repositoryDefaultCompareOrigin(repo) mustEqual "parent-user:some-branch"
     }
   }
+
+  "encodeCompareBranch" should {
+    "not uri encode /" in {
+      helpers.encodeCompareBranch("foo/bar#baz") mustEqual "foo/bar%23baz"
+    }
+
+    "not uri encode :" in {
+      helpers.encodeCompareBranch("foo:bar#baz") mustEqual "foo:bar%23baz"
+    }
+
+    "uri encode special characters" in {
+      helpers.encodeCompareBranch("!#$&'()+,;=?@[]") mustEqual "%21%23%24%26%27%28%29%2B%2C%3B%3D%3F%40%5B%5D"
+    }
+  }
 }