Accessing a nonexisting milestone results in a 500 error, should be a 404

[noerw]

• Gitea version (or commit ref): 1.9.0
• Git version:
• Operating system: Debian 9
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
  • Not relevant
• Log gist:

2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `lower_name`, `name`, `full_name`, `email`, `keep_email_private`, `passwd`, `must_change_password`, `login_type`, `login_source`, `login_name`, `type`, `location`, `website`, `rands`, `salt`, `language`, `description`, `created_unix`, `updated_unix`, `last_login_unix`, `last_repo_visibility`, `max_repo_creation`, `is_active`, `is_admin`, `allow_git_hook`, `allow_import_local`, `allow_create_organization`, `prohibit_login`, `avatar`, `avatar_email`, `use_custom_avatar`, `num_followers`, `num_following`, `num_stars`, `num_repos`, `num_teams`, `num_members`, `visibility`, `diff_view_style`, `theme` FROM `user` WHERE `id`=? LIMIT 1 []interface {}{1}
2019/08/14 17:42:51 .../xorm/session_raw.go:87:queryRow() [I] [SQL] SELECT count(*) FROM `notification` WHERE (user_id = ?) AND (status = ?) []interface {}{1, 0x1}
2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `lower_name`, `name`, `full_name`, `email`, `keep_email_private`, `passwd`, `must_change_password`, `login_type`, `login_source`, `login_name`, `type`, `location`, `website`, `rands`, `salt`, `language`, `description`, `created_unix`, `updated_unix`, `last_login_unix`, `last_repo_visibility`, `max_repo_creation`, `is_active`, `is_admin`, `allow_git_hook`, `allow_import_local`, `allow_create_organization`, `prohibit_login`, `avatar`, `avatar_email`, `use_custom_avatar`, `num_followers`, `num_following`, `num_stars`, `num_repos`, `num_teams`, `num_members`, `visibility`, `diff_view_style`, `theme` FROM `user` WHERE `lower_name`=? LIMIT 1 []interface {}{"ecolibro"}
2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `owner_id`, `lower_name`, `name`, `description`, `website`, `default_branch`, `num_watches`, `num_stars`, `num_forks`, `num_issues`, `num_closed_issues`, `num_pulls`, `num_closed_pulls`, `num_milestones`, `num_closed_milestones`, `is_private`, `is_empty`, `is_archived`, `is_mirror`, `is_fork`, `fork_id`, `size`, `is_fsck_enabled`, `close_issues_via_commit_in_any_branch`, `topics`, `avatar`, `created_unix`, `updated_unix` FROM `repository` WHERE `owner_id`=? AND `lower_name`=? LIMIT 1 []interface {}{5, "eechargis"}
2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `repo_id`, `user_id`, `mode` FROM `collaboration` WHERE `repo_id`=? AND `user_id`=? LIMIT 1 []interface {}{5, 1}
2019/08/14 17:42:51 ...xorm/session_find.go:199:noCacheFind() [I] [SQL] SELECT `id`, `repo_id`, `type`, `config`, `created_unix` FROM `repo_unit` WHERE (repo_id = ?) []interface {}{5}
2019/08/14 17:42:51 .../xorm/session_raw.go:87:queryRow() [I] [SQL] SELECT count(*) FROM `release` WHERE repo_id=? AND is_draft=? []interface {}{5, false}
2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `owner_id`, `lower_name`, `name`, `description`, `website`, `default_branch`, `num_watches`, `num_stars`, `num_forks`, `num_issues`, `num_closed_issues`, `num_pulls`, `num_closed_pulls`, `num_milestones`, `num_closed_milestones`, `is_private`, `is_empty`, `is_archived`, `is_mirror`, `is_fork`, `fork_id`, `size`, `is_fsck_enabled`, `close_issues_via_commit_in_any_branch`, `topics`, `avatar`, `created_unix`, `updated_unix` FROM `repository` WHERE (owner_id=? AND fork_id=?) LIMIT 1 []interface {}{1, 5}
2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `user_id`, `repo_id` FROM `watch` WHERE `user_id`=? AND `repo_id`=? LIMIT 1 []interface {}{1, 5}
2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `uid`, `repo_id` FROM `star` WHERE `uid`=? AND `repo_id`=? LIMIT 1 []interface {}{1, 5}
2019/08/14 17:42:51 .../xorm/session_get.go:99:nocacheGet() [I] [SQL] SELECT `id`, `repo_id`, `name`, `content`, `is_closed`, `num_issues`, `num_closed_issues`, `completeness`, `deadline_unix`, `closed_date_unix` FROM `milestone` WHERE `id`=? LIMIT 1 []interface {}{6}
2019/08/14 17:42:51 ...rs/repo/milestone.go:256:MilestoneIssuesAndPulls() [E] GetMilestoneByID: milestone does not exist [id: 6, repo_id: 0]

Description

Accessing a non existing or deleted milestone via the frontend results in a 500 error, should be a 404.