Internal error when editing description of an issue

Summary

Editing a description of a bug report results in an internal error.

Steps to reproduce

The issue in question is https://gitlab.gnome.org/GNOME/Infrastructure/issues/8. The original text is:

Let's have a tracker bug for issues that are affecting us and are GitLab upstream.

# Major
* [x] Upstream report about some major requirements made by GNOME discussed with GitLab https://gitlab.com/gitlab-org/gitlab-ce/issues/35287
* [ ] Ability to merge duplicated issues. Cannot find upstream report, maybe https://gitlab.com/gitlab-org/gitlab-ce/issues/26372 is related? However it's missing basic UI.
* [ ] Identifying our instance as official GNOME is difficult with the new navigation https://gitlab.gnome.org/GNOME/Infrastructure/issues/19.
* [ ] External users cannot create forks, preventing external contributions https://gitlab.gnome.org/GNOME/Infrastructure/issues/18, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/15173. I have the feeling this might be us misconstruing something or misunderstanding some workflow.
* [ ] Dependencies between issues https://gitlab.gnome.org/GNOME/Infrastructure/issues/17, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/4058. Seems this one is going to be difficult to become free software.

# Minor
* [ ] If we are going to use the description to put related issues to be tracked as a workaround for not having built-in support for "relation between issues", we might need to have a way to remove all the "User changed the description" meta messages or collapse them.

# Wishlist
* And, not, or operands for search https://gitlab.com/gitlab-org/gitlab-ce/issues/27747

And target text is just modifying last line to add "[ ]" between the "*" and the "And", resulting in:

Let's have a tracker bug for issues that are affecting us and are GitLab upstream.

# Major
* [x] Upstream report about some major requirements made by GNOME discussed with GitLab https://gitlab.com/gitlab-org/gitlab-ce/issues/35287
* [ ] Ability to merge duplicated issues. Cannot find upstream report, maybe https://gitlab.com/gitlab-org/gitlab-ce/issues/26372 is related? However it's missing basic UI.
* [ ] Identifying our instance as official GNOME is difficult with the new navigation https://gitlab.gnome.org/GNOME/Infrastructure/issues/19.
* [ ] External users cannot create forks, preventing external contributions https://gitlab.gnome.org/GNOME/Infrastructure/issues/18, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/15173. I have the feeling this might be us misconstruing something or misunderstanding some workflow.
* [ ] Dependencies between issues https://gitlab.gnome.org/GNOME/Infrastructure/issues/17, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/4058. Seems this one is going to be difficult to become free software.

# Minor
* [ ] If we are going to use the description to put related issues to be tracked as a workaround for not having built-in support for "relation between issues", we might need to have a way to remove all the "User changed the description" meta messages or collapse them.

# Wishlist
* [ ] And, not, or operands for search https://gitlab.com/gitlab-org/gitlab-ce/issues/27747

Example Project

I cannot reproduce here in gitlab.com

What is the current bug behavior?

An error in banner mode appears

What is the expected correct behavior?

Edit is done succesfully

Relevant logs and/or screenshots

Processing by Projects::IssuesController#update as JSON
Parameters: {"title"=>"Tracker bug for upstream GitLab", "description"=>"Let's have a tracker bug for issues that are affecting us and are GitLab upstream.\n\n# Major\n* [ ] Upstream report about some major requirements made by GNOME discussed with GitLab https://gitlab.com/gitlab-org/gitlab-ce/issues/35287\n* [ ] Ability to merge duplicated issues. Cannot find upstream report, maybe https://gitlab.com/gitlab-org/gitlab-ce/issues/26372 is related? However it's missing basic UI.\n* [ ] Identifying our instance as official GNOME is difficult with the new navigation https://gitlab.gnome.org/GNOME/Infrastructure/issues/19.\n* [ ] External users cannot create forks, preventing external contributions https://gitlab.gnome.org/GNOME/Infrastructure/issues/18, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/15173. I have the feeling this might be us misconstruing something or misunderstanding some workflow.\n* [ ] Dependencies between issues https://gitlab.gnome.org/GNOME/Infrastructure/issues/17, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/4058. Seems this one is going to be difficult to become free software.\n\n# Minor\n* [ ] If we are going to use the description to put related issues to be tracked as a workaround for not having built-in support for \"relation between issues\", we might need to have a way to remove all the \"User changed the description\" meta messages or collapse them.\n\n# Wishlist\n* And, not, or operands for search https://gitlab.com/gitlab-org/gitlab-ce/issues/27747", "lockedWarningVisible"=>false, "updateLoading"=>true, "namespace_id"=>"GNOME", "project_id"=>"Infrastructure", "id"=>"8", "issue"=>{"title"=>"Tracker bug for upstream GitLab", "description"=>"Let's have a tracker bug for issues that are affecting us and are GitLab upstream.\n\n# Major\n* [ ] Upstream report about some major requirements made by GNOME discussed with GitLab https://gitlab.com/gitlab-org/gitlab-ce/issues/35287\n* [ ] Ability to merge duplicated issues. Cannot find upstream report, maybe https://gitlab.com/gitlab-org/gitlab-ce/issues/26372 is related? However it's missing basic UI.\n* [ ] Identifying our instance as official GNOME is difficult with the new navigation https://gitlab.gnome.org/GNOME/Infrastructure/issues/19.\n* [ ] External users cannot create forks, preventing external contributions https://gitlab.gnome.org/GNOME/Infrastructure/issues/18, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/15173. I have the feeling this might be us misconstruing something or misunderstanding some workflow.\n* [ ] Dependencies between issues https://gitlab.gnome.org/GNOME/Infrastructure/issues/17, upstream: https://gitlab.com/gitlab-org/gitlab-ce/issues/4058. Seems this one is going to be difficult to become free software.\n\n# Minor\n* [ ] If we are going to use the description to put related issues to be tracked as a workaround for not having built-in support for \"relation between issues\", we might need to have a way to remove all the \"User changed the description\" meta messages or collapse them.\n\n# Wishlist\n* And, not, or operands for search https://gitlab.com/gitlab-org/gitlab-ce/issues/27747"}}
Completed 422 Unprocessable Entity in 208ms (Views: 0.4ms | ActiveRecord: 7.6ms)

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:     RedHatEnterpriseServer 7.4
Current User:   git
Using RVM:  no
Ruby Version:   2.3.5p376
Gem Version:    2.6.13
Bundler Version:1.13.7
Rake Version:   12.0.0
Redis Version:  3.2.5
Git Version:    2.13.5
Sidekiq Version:5.0.4
Go Version: unknown
GitLab information
Version:    10.0.1
Revision:   2417795
Directory:  /opt/gitlab/embedded/service/gitlab-rails
DB Adapter: postgresql
URL:        https://gitlab.gnome.org
HTTP Clone URL: https://gitlab.gnome.org/some-group/some-project.git
SSH Clone URL:  git@gitlab.gnome.org:some-group/some-project.git
Using LDAP: yes
Using Omniauth: yes
Omniauth Providers: google_oauth2, github
GitLab Shell
Version:    5.9.0
Repository storage paths:

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

Possible fixes

We have the feeling this is due to some invalid character in the generated code.