Merge branch 'refactoring_find_commits_method' into 'master'

Refactoring find_commits method

It's possible that `find_commits_by_message` return nil in array which is not OK. We have different checks outside of this method. This MR places all checks inside the method.

See merge request !7000

app/controllers/projects/commits_controller.rb

@@ -13,7 +13,7 @@ class Projects::CommitsController < Projects::ApplicationController
 
     @commits =
       if search.present?
-        @repository.find_commits_by_message(search, @ref, @path, @limit, @offset).compact
+        @repository.find_commits_by_message(search, @ref, @path, @limit, @offset)
       else
         @repository.commits(@ref, path: @path, limit: @limit, offset: @offset)
       end

app/models/repository.rb

@@ -109,6 +109,10 @@ class Repository
   end
 
   def find_commits_by_message(query, ref = nil, path = nil, limit = 1000, offset = 0)
+    unless exists? && has_visible_content? && query.present?
+      return []
+    end
+
     ref ||= root_ref
 
     args = %W(
@@ -117,9 +121,8 @@ class Repository
     )
     args = args.concat(%W(-- #{path})) if path.present?
 
-    git_log_results = Gitlab::Popen.popen(args, path_to_repo).first.lines.map(&:chomp)
-    commits = git_log_results.map { |c| commit(c) }
-    commits
+    git_log_results = Gitlab::Popen.popen(args, path_to_repo).first.lines
+    git_log_results.map { |c| commit(c.chomp) }.compact
   end
 
   def find_branch(name, fresh_repo: true)

lib/gitlab/project_search_results.rb

@@ -73,11 +73,7 @@ module Gitlab
     end
 
     def commits
-      if project.empty_repo? || query.blank?
-        []
-      else
-        project.repository.find_commits_by_message(query).compact
-      end
+      project.repository.find_commits_by_message(query)
     end
 
     def project_ids_relation