Don't show revert button if commit/MR has already been reverted.

2 files changed, 30 insertions, 6 deletions

diff --git a/app/models/commit.rb b/app/models/commit.rb
index 38bbc24fbfc..628926e4886 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -219,14 +219,20 @@ class Commit
     "revert-#{short_id}"
   end
 
+  def revert_description
+    if merged_merge_request
+      "This reverts merge request #{merged_merge_request.to_reference}"
+    else
+      "This reverts commit #{sha}"
+    end
+  end
+
   def revert_message
-    description = if merged_merge_request
-                    "This reverts merge request #{merged_merge_request.to_reference}"
-                  else
-                    "This reverts commit #{sha}"
-                  end
+    "Revert \"#{title}\"" + "\n\n#{revert_description}"
+  end
 
-    "Revert \"#{title}\"" + "\n\n#{description}"
+  def reverts_commit?(commit)
+    description.include?(commit.revert_description)
   end
 
   def merge_commit?
@@ -239,6 +245,14 @@ class Commit
     @merged_merge_request = merge_commit? && MergeRequest.find_by(merge_commit_sha: id)
   end
 
+  def has_been_reverted?(current_user = nil, noteable = self)
+    Gitlab::ReferenceExtractor.lazily do
+      [self, *noteable.notes].flat_map do |note|
+        note.all_references(current_user).commits
+      end
+    end.any? { |commit_ref| commit_ref.reverts_commit?(self) }
+  end
+
   private
 
   def repo_changes
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 8eb201b154d..82d096989cf 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -533,4 +533,14 @@ class MergeRequest < ActiveRecord::Base
 
     [diff_base_commit, last_commit]
   end
+
+  def merge_commit
+    @merge_commit ||= project.commit(merge_commit_sha) if merge_commit_sha
+  end
+
+  def has_been_reverted?(current_user = nil)
+    if merge_commit
+      merge_commit.has_been_reverted?(current_user, self)
+    end
+  end
 end