Include more information in hook error messages

When pushing commits to the remote, if a pre-receive hook gets triggered that prevents the push, it may not be clear which commit is causing the issue. Having the values of what caused the comparison to fail in the error message will help debugging, whether it be the user or the administrator.

lib/gitlab/git_access.rb

@@ -197,29 +197,29 @@ module Gitlab
         commits.each do |commit|
           if git_hook.commit_message_regex.present?
             unless commit.safe_message =~ Regexp.new(git_hook.commit_message_regex)
-              return build_status_object(false, "Commit message does not follow the pattern")
+              return build_status_object(false, "Commit message does not follow the pattern '#{git_hook.commit_message_regex}'")
             end
           end
 
           if git_hook.author_email_regex.present?
             unless commit.committer_email =~ Regexp.new(git_hook.author_email_regex)
-              return build_status_object(false, "Commiter's email does not follow the pattern")
+              return build_status_object(false, "Committer's email '#{commit.committer_email}' does not follow the pattern '#{git_hook.author_email_regex}'")
             end
 
             unless commit.author_email =~ Regexp.new(git_hook.author_email_regex)
-              return build_status_object(false, "Author's email does not follow the pattern")
+              return build_status_object(false, "Author's email '#{commit.author_email}' does not follow the pattern '#{git_hook.author_email_regex}'")
             end
           end
 
           # Check whether author is a GitLab member
           if git_hook.member_check
             unless User.existing_member?(commit.author_email)
-              return build_status_object(false, "Author is not a member of team")
+              return build_status_object(false, "Author '#{commit.author_email}' is not a member of team")
             end
 
             if commit.author_email != commit.committer_email
               unless User.existing_member?(commit.committer_email)
-                return build_status_object(false, "Commiter is not a member of team")
+                return build_status_object(false, "Committer '#{commit.committer_email}' is not a member of team")
               end
             end
           end
@@ -227,7 +227,7 @@ module Gitlab
           if git_hook.file_name_regex.present?
             commit.diffs.each do |diff|
               if (diff.renamed_file || diff.new_file) && diff.new_path =~ Regexp.new(git_hook.file_name_regex)
-                return build_status_object(false, "File name #{diff.new_path.inspect} does not follow the pattern")
+                return build_status_object(false, "File name #{diff.new_path.inspect} does not follow the pattern '#{git_hook.file_name_regex}'")
               end
             end
           end