MergeRequest#new 2 step process

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

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

+%h3.page-title Compare changes for new merge request
+%hr
+
+= form_for [@project, @merge_request], url: new_project_merge_request_path(@project), method: :get, html: { class: "merge-request-form form-inline" } do |f|
+  .merge-request-branches.row
+    .col-md-6
+      .panel.panel-default
+        .panel-heading
+          From
+        .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? })
+           
+          = f.select(:source_branch, @merge_request.source_branches, { include_blank: "Select branch" }, {class: 'source_branch select2 span2'})
+        .panel-footer
+          .mr_source_commit
+
+    .col-md-6
+      .panel.panel-default
+        .panel-heading
+          To
+        .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? })
+           
+          = f.select(:target_branch, @merge_request.target_branches, { include_blank: "Select branch" }, {class: 'target_branch select2 span2'})
+        .panel-footer
+          .mr_target_commit
+
+  -if @merge_request.errors.any?
+    .alert.alert-danger
+      - @merge_request.errors.full_messages.each do |msg|
+        %div= msg
+
+  - if @merge_request.source_branch.present? && @merge_request.target_branch.present?
+    .light-well
+      %center
+        %h4
+          There isn't anything to merge.
+        %p.slead
+          - if @merge_request.source_branch == @merge_request.target_branch
+            You'll need to use different branch names to get a valid comparison.
+          - else
+            %span.label-branch #{@merge_request.source_branch}
+            and
+            %span.label-branch #{@merge_request.target_branch}
+            are the same.
+
+  .form-actions
+    = f.submit 'Compare branches', class: "btn btn-primary"
+
+:javascript
+  var source_branch = $("#merge_request_source_branch")
+    , target_branch = $("#merge_request_target_branch")
+    , target_project = $("#merge_request_target_project_id");
+
+  $.get("#{branch_from_project_merge_requests_path(@source_project)}", {ref: source_branch.val() });
+  $.get("#{branch_to_project_merge_requests_path(@source_project)}", {target_project_id: target_project.val(),ref: target_branch.val() });
+
+  target_project.on("change", function() {
+    $.get("#{update_branches_project_merge_requests_path(@source_project)}", {target_project_id:  $(this).val() });
+  });
+  source_branch.on("change", function() {
+    $.get("#{branch_from_project_merge_requests_path(@source_project)}", {ref: $(this).val() });
+  });
+  target_branch.on("change", function() {
+    $.get("#{branch_to_project_merge_requests_path(@source_project)}", {target_project_id: target_project.val(),ref: $(this).val() });
+  });
+
+

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

+%h3.page-title
+  New merge request
+%p.slead
+  From
+  %strong.monospace
+    #{@merge_request.source_project_namespace}:#{@merge_request.source_branch}
+  into
+  %strong.monospace
+    #{@merge_request.target_project_namespace}:#{@merge_request.target_branch}
+
+  %span.pull-right
+    = link_to 'Change branches', new_project_merge_request_path(@project)
+
+= form_for [@project, @merge_request], html: { class: "merge-request-form" } do |f|
+  .panel.panel-default
+
+    .panel-body
+      .form-group
+        .light
+          = f.label :title do
+            = "Title *"
+        = f.text_field :title, class: "form-control input-lg js-gfm-input", maxlength: 255, rows: 5, required: true
+      .form-group
+        .light
+          = f.label :description, "Description"
+        = f.text_area :description, class: "form-control js-gfm-input", rows: 10
+        %p.hint Description is parsed with #{link_to "GitLab Flavored Markdown", help_markdown_path, target: '_blank'}.
+    .panel-footer
+      - if @target_repo.contribution_guide
+        - contribution_guide_url = project_blob_path(@target_project, tree_join(@target_repo.root_ref, @target_repo.contribution_guide.name))
+        %p
+          Please review the
+          %strong #{link_to "guidelines for contribution", contribution_guide_url}
+          to this repository.
+      = f.hidden_field :source_project_id
+      = f.hidden_field :target_project_id
+      = f.hidden_field :target_branch
+      = f.hidden_field :source_branch
+      = f.submit 'Submit a merge request', class: "btn btn-create"
+
+.mr-compare
+  %div.ui-box
+    .title
+      Commits (#{@commits.count})
+    - if @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
+      %ul.well-list
+        - Commit.decorate(@commits.first(MergeRequestDiff::COMMITS_SAFE_SIZE)).each do |commit|
+          = render "projects/commits/inline_commit", commit: commit, project: @project
+        %li.warning-row.unstyled
+          other #{@commits.size - MergeRequestDiff::COMMITS_SAFE_SIZE} commits hidden to prevent performance issues.
+    - else
+      %ul.well-list= render Commit.decorate(@commits), project: @project
+
+  %h4 Changes
+  - if @diffs.present?
+    = render "projects/commits/diffs", diffs: @diffs, project: @project
+  - elsif @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
+    .bs-callout.bs-callout-danger
+      %h4 This comparison includes more than #{MergeRequestDiff::COMMITS_SAFE_SIZE} commits.
+      %p To preserve performance the line changes are not shown.

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

-%h3.page-title New Merge Request
-%hr
-= render 'form'
+- if @commits.present?
+  = render 'new_submit'
+- else
+  = render 'new_compare'