Disable / hide MR edit blob button if cannot edit.

app/helpers/tree_helper.rb

@@ -53,13 +53,34 @@ module TreeHelper
     File.join(*args)
   end
 
-  def allowed_tree_edit?
-    return false unless @repository.branch_names.include?(@ref)
+  def allowed_tree_edit?(project = nil, ref = nil)
+    project ||= @project
+    ref ||= @ref
+    return false unless project.repository.branch_names.include?(ref)
 
-    if @project.protected_branch? @ref
-      can?(current_user, :push_code_to_protected_branches, @project)
+    if project.protected_branch? ref
+      can?(current_user, :push_code_to_protected_branches, project)
     else
-      can?(current_user, :push_code, @project)
+      can?(current_user, :push_code, project)
+    end
+  end
+
+  def edit_blob_link(project, ref, path, options = {})
+    if project.repository.blob_at(ref, path).text?
+      text = 'Edit'
+      after = options[:after] || ''
+      from_mr = options[:from_merge_request_id]
+      link_opts = {}
+      link_opts[:from_merge_request_id] = from_mr if from_mr
+      cls = 'btn btn-small'
+      if allowed_tree_edit?(project, ref)
+        link_to text, project_edit_tree_path(project, tree_join(ref, path),
+                                             link_opts), class: cls
+      else
+        content_tag :span, text, class: cls + ' disabled'
+      end + after.html_safe
+    else
+      ''
     end
   end
 

app/views/projects/blob/_actions.html.haml

 .btn-group.tree-btn-group
-  -# only show edit link for text files
-  - if @blob.text?
-    - if allowed_tree_edit?
-      = link_to 'Edit', project_edit_tree_path(@project, @id),
-          class: 'btn btn-small'
-    - else
-      %span.btn.btn-small.disabled Edit
+  = edit_blob_link(@project, @ref, @path)
   = link_to 'Raw', project_raw_path(@project, @id),
       class: 'btn btn-small', target: '_blank'
   -# only show normal/blame view links for text files

app/views/projects/diffs/_file.html.haml

@@ -27,9 +27,9 @@
            
 
         - if @merge_request && @merge_request.source_project
-          = link_to project_edit_tree_path(@merge_request.source_project, tree_join(@merge_request.source_branch, diff_file.new_path), from_merge_request_id: @merge_request.id), { class: 'btn btn-small' } do
-            Edit
-           
+          = edit_blob_link(@merge_request.source_project,
+              @merge_request.source_branch, diff_file.new_path,
+              after: ' ', from_merge_request_id: @merge_request.id)
 
         = view_file_btn(@commit.id, diff_file, project)