Fix unnecessary master branch references

Default branch or main naming is encouraged

lib/api/commits.rb

@@ -47,7 +47,7 @@ module API
         path = params[:path]
         before = params[:until]
         after = params[:since]
-        ref = params[:ref_name].presence || user_project.try(:default_branch) || 'master' unless params[:all]
+        ref = params[:ref_name].presence || user_project.default_branch unless params[:all]
         offset = (params[:page] - 1) * params[:per_page]
         all = params[:all]
         with_stats = params[:with_stats]

lib/api/helpers/groups_helpers.rb

@@ -23,7 +23,7 @@ module API
         optional :mentions_disabled, type: Boolean, desc: 'Disable a group from getting mentioned'
         optional :lfs_enabled, type: Boolean, desc: 'Enable/disable LFS for the projects in this group'
         optional :request_access_enabled, type: Boolean, desc: 'Allow users to request member access'
-        optional :default_branch_protection, type: Integer, values: ::Gitlab::Access.protection_values, desc: 'Determine if developers can push to master'
+        optional :default_branch_protection, type: Integer, values: ::Gitlab::Access.protection_values, desc: 'Determine if developers can push to default branch'
         optional :shared_runners_setting, type: String, values: ::Namespace::SHARED_RUNNERS_SETTINGS, desc: 'Enable/disable shared runners for the group and its subgroups and projects'
       end
 

lib/api/repositories.rb

@@ -55,7 +55,7 @@ module API
         use :pagination
       end
       get ':id/repository/tree' do
-        ref = params[:ref] || user_project.try(:default_branch) || 'master'
+        ref = params[:ref] || user_project.default_branch
         path = params[:path] || nil
 
         commit = user_project.commit(ref)

lib/api/settings.rb

@@ -48,7 +48,7 @@ module API
       optional :default_artifacts_expire_in, type: String, desc: "Set the default expiration time for each job's artifacts"
       optional :default_ci_config_path, type: String, desc: 'The instance default CI/CD configuration file and path for new projects'
       optional :default_project_creation, type: Integer, values: ::Gitlab::Access.project_creation_values, desc: 'Determine if developers can create projects in the group'
-      optional :default_branch_protection, type: Integer, values: ::Gitlab::Access.protection_values, desc: 'Determine if developers can push to master'
+      optional :default_branch_protection, type: Integer, values: ::Gitlab::Access.protection_values, desc: 'Determine if developers can push to default branch'
       optional :default_group_visibility, type: String, values: Gitlab::VisibilityLevel.string_values, desc: 'The default group visibility'
       optional :default_project_visibility, type: String, values: Gitlab::VisibilityLevel.string_values, desc: 'The default project visibility'
       optional :default_projects_limit, type: Integer, desc: 'The maximum number of personal projects'

lib/gitlab/checks/branch_check.rb

@@ -122,7 +122,7 @@ module Gitlab
       def empty_project_push_message
         <<~MESSAGE
 
-        A default branch (e.g. master) does not yet exist for #{project.full_path}
+        A default branch (e.g. main) does not yet exist for #{project.full_path}
         Ask a project Owner or Maintainer to create a default branch:
 
           #{project_members_url}