Create/Edit Slack Service: cannot set 'username' field via API

Summary

Trying to create/edit a Slack Service with the PUT command and body format prescribed in these docs updates all fields except the username.

Steps to reproduce

1. Created a project
2. From Postman, created a PUT request with the body as prescribed
3. Click send

Example Project

https://gitlab.com/mdhornet90/A-Buggy-Project

• It actually seems even more broken on gitlab.com, I can't even get the "webhook" to stick during update.

What is the current bug behavior?

The username field is neither created nor updated.

What is the expected correct behavior?

That the username field is either created or updated.

Relevant logs and/or screenshots

REQUEST BODY (username previously set to "Why No work?")
{
    "channel" : "dev_channel",
    "webhook" : "http://192.168.0.102:5000",
    "username" : "doesnotmatter"
}

RESPONSE BODY
{
    "id": 7,
    "title": "Slack notifications",
    "created_at": "2017-11-18T20:36:31.738Z",
    "updated_at": "2017-11-19T04:09:22.919Z",
    "active": true,
    "push_events": true,
    "issues_events": true,
    "merge_requests_events": true,
    "tag_push_events": true,
    "note_events": true,
    "pipeline_events": true,
    "job_events": true,
    "properties": {
        "webhook": "http://192.168.0.102:5000",
        "username": "Why No work?",
        "notify_only_broken_pipelines": "0",
        "notify_only_default_branch": "0",
        "push_channel": "",
        "issue_channel": "",
        "confidential_issue_channel": "",
        "merge_request_channel": "",
        "note_channel": "",
        "tag_push_channel": "",
        "pipeline_channel": "",
        "wiki_page_channel": ""
    }
}

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:
Current User:	git
Using RVM:	no
Ruby Version:	2.3.5p376
Gem Version:	2.6.13
Bundler Version:1.13.7
Rake Version:	12.1.0
Redis Version:	3.2.5
Git Version:	2.13.6
Sidekiq Version:5.0.4
Go Version:	unknown
GitLab information
Version:	10.1.4
Revision:	c887c03
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
URL:		http://11eef1634270
HTTP Clone URL:	http://11eef1634270/some-group/some-project.git
SSH Clone URL:	git@11eef1634270:some-group/some-project.git
Using LDAP:	no
Using Omniauth:	no
GitLab Shell
Version:	5.9.3
Repository storage paths:

• default: /var/opt/gitlab/git-data/repositories Hooks: /opt/gitlab/embedded/service/gitlab-shell/hooks Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab Shell ...
GitLab Shell version >= 5.9.3 ? ... OK (5.9.3)
Repo base directory exists?
default... yes
Repo storage directories are symlinks?
default... no
Repo paths owned by git:root, or git:git?
default... yes
Repo paths access is drwxrws---?
default... yes
hooks directories in repos are links: ...
2/21 ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Sidekiq ...
Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Reply by email is disabled in config/gitlab.yml
Checking LDAP ...
LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... skipped (no tmp uploads folder yet)
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
2/21 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.3 ? ... yes (2.3.5)
Git version >= 2.7.3 ? ... yes (2.13.6)
Git user has default SSH configuration? ... yes
Active users: ... 1
Checking GitLab ... Finished

Possible fixes

¯\(°_o)/¯