1 files changed, 19 insertions, 41 deletions

diff --git a/app/services/merge_requests/merge_service.rb b/app/services/merge_requests/merge_service.rb
index 449997bcf07..d8a78001b79 100644
--- a/app/services/merge_requests/merge_service.rb
+++ b/app/services/merge_requests/merge_service.rb
@@ -7,13 +7,7 @@ module MergeRequests
   # mark merge request as merged and execute all hooks and notifications
   # Executed when you do merge via GitLab UI
   #
-  class MergeService < MergeRequests::BaseService
-    include Gitlab::Utils::StrongMemoize
-
-    MergeError = Class.new(StandardError)
-
-    attr_reader :merge_request, :source
-
+  class MergeService < MergeRequests::MergeBaseService
     delegate :merge_jid, :state, to: :@merge_request
 
     def execute(merge_request)
@@ -24,7 +18,7 @@ module MergeRequests
 
       @merge_request = merge_request
 
-      error_check!
+      validate!
 
       merge_request.in_locked_state do
         if commit
@@ -38,22 +32,22 @@ module MergeRequests
       handle_merge_error(log_message: e.message, save_message_on_model: true)
     end
 
-    def source
-      if merge_request.squash
-        squash_sha!
-      else
-        merge_request.diff_head_sha
-      end
-    end
+    private
 
-    # Overridden in EE.
-    def hooks_validation_pass?(_merge_request)
-      true
+    def validate!
+      authorization_check!
+      error_check!
     end
 
-    private
+    def authorization_check!
+      unless @merge_request.can_be_merged_by?(current_user)
+        raise_error('You are not allowed to merge this merge request')
+      end
+    end
 
     def error_check!
+      super
+
       error =
         if @merge_request.should_be_rebased?
           'Only fast-forward merge is allowed for your project. Please update your source branch'
@@ -63,7 +57,7 @@ module MergeRequests
           'No source for merge'
         end
 
-      raise MergeError, error if error
+      raise_error(error) if error
     end
 
     def commit
@@ -73,36 +67,20 @@ module MergeRequests
       if commit_id
         log_info("Git merge finished on JID #{merge_jid} commit #{commit_id}")
       else
-        raise MergeError, 'Conflicts detected during merge'
+        raise_error('Conflicts detected during merge')
       end
 
       merge_request.update!(merge_commit_sha: commit_id)
     end
 
-    def squash_sha!
-      strong_memoize(:squash_sha) do
-        params[:merge_request] = merge_request
-        squash_result = ::MergeRequests::SquashService.new(project, current_user, params).execute
-
-        case squash_result[:status]
-        when :success
-          squash_result[:squash_sha]
-        when :error
-          raise ::MergeRequests::MergeService::MergeError, squash_result[:message]
-        end
-      end
-    end
-
     def try_merge
-      message = params[:commit_message] || merge_request.default_merge_commit_message
-
-      repository.merge(current_user, source, merge_request, message)
+      repository.merge(current_user, source, merge_request, commit_message)
     rescue Gitlab::Git::PreReceiveError => e
-      handle_merge_error(log_message: e.message)
-      raise MergeError, 'Something went wrong during merge pre-receive hook'
+      raise MergeError,
+            "Something went wrong during merge pre-receive hook. #{e.message}".strip
     rescue => e
       handle_merge_error(log_message: e.message)
-      raise MergeError, 'Something went wrong during merge'
+      raise_error('Something went wrong during merge')
     ensure
       merge_request.update!(in_progress_merge_commit_sha: nil)
     end