Merge branch 'fix-404-empty-repo' into 'master'

Fix 404 error in files view after deleting the last file in a repository

Here's the logic:

1. In `TreeController`, `require_non_empty_project` will prevent `show` from being called if the project is  empty. That means all calls to `show` will be guaranteed to have at least 1 commit.
2. If the ref name is not valid, then return a 404. This ensures that at least the controller is looking at a valid branch/tag/SHA ID.
3. This leaves a number of cases:

```
3a. Valid ref, valid directory
3b. Valid ref, valid filename
3c. Valid ref, invalid path
3d. Valid ref, no files
```

Case 3a: The tree will not be `empty?` and will pass through the whole function.

Case 3b: The tree will be `empty?` but the `blob_at` will resolve properly and trigger a redirect to the file.

Case 3c: In this case, a path is given. Return 404 if it cannot be resolved neither as a tree nor a blob.

Case 3d: In this case, no path is given. If the tree is empty, this means it's an empty branch and just fall through.

Example broken branch: https://gitlab.com/gitlab-org/gitlab-test/tree/empty-branch

Closes #1362

See merge request !1010

1 files changed, 3 insertions, 1 deletions

diff --git a/app/controllers/projects/tree_controller.rb b/app/controllers/projects/tree_controller.rb
index b659e15f242..92e4bc16d9d 100644
--- a/app/controllers/projects/tree_controller.rb
+++ b/app/controllers/projects/tree_controller.rb
@@ -7,13 +7,15 @@ class Projects::TreeController < Projects::ApplicationController
   before_action :authorize_download_code!
 
   def show
+    return not_found! unless @repository.commit(@ref)
+
     if tree.entries.empty?
       if @repository.blob_at(@commit.id, @path)
         redirect_to(
           namespace_project_blob_path(@project.namespace, @project,
                                       File.join(@ref, @path))
         ) and return
-      else
+      elsif @path.present?
         return not_found!
       end
     end