Dont allow mr compare with empty branches

app/views/projects/merge_requests/_new_compare.html.haml

@@ -2,11 +2,12 @@
 %hr
 
 = form_for [@project, @merge_request], url: new_project_merge_request_path(@project), method: :get, html: { class: "merge-request-form form-inline" } do |f|
+  .hide.alert.alert-danger.mr-compare-errors
   .merge-request-branches.row
     .col-md-6
       .panel.panel-default
         .panel-heading
-          From
+          %strong Source branch
         .panel-body
           = f.select(:source_project_id, [[@merge_request.source_project_path,@merge_request.source_project.id]] , {}, { class: 'source_project select2 span3', disabled: @merge_request.persisted? })
            
@@ -17,7 +18,7 @@
     .col-md-6
       .panel.panel-default
         .panel-heading
-          To
+          %strong Target branch
         .panel-body
           - projects =  @project.forked_from_project.nil? ? [@project] : [@project, @project.forked_from_project]
           = f.select(:target_project_id, options_from_collection_for_select(projects, 'id', 'path_with_namespace', f.object.target_project_id), {}, { class: 'target_project select2 span3', disabled: @merge_request.persisted? })
@@ -45,8 +46,9 @@
             %span.label-branch #{@merge_request.target_branch}
             are the same.
 
+
   %hr
-  = f.submit 'Compare branches', class: "btn btn-primary"
+  = f.submit 'Compare branches', class: "btn btn-primary mr-compare-btn"
 
 :javascript
   var source_branch = $("#merge_request_source_branch")
@@ -61,9 +63,22 @@
   });
   source_branch.on("change", function() {
     $.get("#{branch_from_project_merge_requests_path(@source_project)}", {ref: $(this).val() });
+    $(".mr-compare-errors").fadeOut();
+    $(".mr-compare-btn").enable();
   });
   target_branch.on("change", function() {
     $.get("#{branch_to_project_merge_requests_path(@source_project)}", {target_project_id: target_project.val(),ref: $(this).val() });
+    $(".mr-compare-errors").fadeOut();
+    $(".mr-compare-btn").enable();
   });
 
 
+:coffeescript
+
+  $(".merge-request-form").on 'submit', ->
+    if $("#merge_request_source_branch").val() is "" or $('#merge_request_target_branch').val() is ""
+      $(".mr-compare-errors").html("You must select source and target branch to proceed")
+      $(".mr-compare-errors").fadeIn()
+      event.preventDefault()
+      return
+

features/project/forked_merge_requests.feature

@@ -30,11 +30,10 @@ Feature: Project Forked Merge Requests
     Given I visit project "Forked Shop" merge requests page
     And I click link "New Merge Request"
     And I fill out an invalid "Merge Request On Forked Project" merge request
-    And I submit the merge request
     Then I should see validation errors
 
   @javascript
   Scenario: Merge request should target fork repository by default
     Given I visit project "Forked Shop" merge requests page
     And I click link "New Merge Request"
-    Then the target repository should be the original repository
+    Then the target repository should be the original repository
\ No newline at end of file

features/steps/project/forked_merge_requests.rb

@@ -53,6 +53,7 @@ class ProjectForkedMergeRequests < Spinach::FeatureSteps
 
     find(:select, "merge_request_source_branch", {}).value.should == 'master'
     find(:select, "merge_request_target_branch", {}).value.should == 'stable'
+    click_button "Compare branches"
 
     fill_in "merge_request_title", with: "Merge Request On Forked Project"
   end
@@ -148,29 +149,19 @@ class ProjectForkedMergeRequests < Spinach::FeatureSteps
     current_path.should == edit_project_merge_request_path(@project, @merge_request)
     page.should have_content "Edit merge request ##{@merge_request.id}"
     find("#merge_request_title").value.should == "Merge Request On Forked Project"
-    find("#merge_request_source_project_id").value.should == @forked_project.id.to_s
-    find("#merge_request_target_project_id").value.should == @project.id.to_s
-    find("#merge_request_source_branch").value.should have_content "master"
-    verify_commit_link(".mr_source_commit",@forked_project)
-    find("#merge_request_target_branch").value.should have_content "stable"
-    verify_commit_link(".mr_target_commit",@project)
   end
 
   step 'I fill out an invalid "Merge Request On Forked Project" merge request' do
-    #If this isn't filled in the rest of the validations won't be triggered
-    fill_in "merge_request_title", with: "Merge Request On Forked Project"
-
     select "Select branch", from: "merge_request_target_branch"
-
     find(:select, "merge_request_source_project_id", {}).value.should == @forked_project.id.to_s
     find(:select, "merge_request_target_project_id", {}).value.should == project.id.to_s
     find(:select, "merge_request_source_branch", {}).value.should == ""
     find(:select, "merge_request_target_branch", {}).value.should == ""
+    click_button "Compare branches"
   end
 
   step 'I should see validation errors' do
-    page.should have_content "Source branch can't be blank"
-    page.should have_content "Target branch can't be blank"
+    page.should have_content "You must select source and target branch"
   end
 
   step 'the target repository should be the original repository' do