Merge request - https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6979

Fix branch protection API.

## What does this MR do?

- Fixes the branch protection API.
- Closes #21513 
- EE Merge Request: gitlab-org/gitlab-ee!718

## Tasks

- [ ]  #21513 !6215 Protected branches API bug
    - [x]  Investigate
    - [x]  Test + Fix
    - [x]  Changelog
    - [x]  MR
    - [x]  Wait for build to pass
    - [x]  Review
    - [x]  Check for EE conflicts
    - [x]  Create EE MR
    - [x]  Refactor + Fix
    - [x]  Rebase EE MR against EE master
    - [x]  Wait for builds to pass
    - [x]  Assign to dbalexandre/douwe
    - [x]  Implement latest review comments
    - [x]  Wait for Douwe's review
        - [x]  Implement changes
        - [x]  Port changes to EE MR
        - [x]  Assign both back to Douwe
    - [ ]  Wait for merge
    - [ ]  Merge gitlab-org/gitlab-ee!718

See merge request !6215

Fix constrainers for relative url

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/23675

See merge request !7071

Use root_url for issue boards user link

## What does this MR do?

Rather than using `/` as the root path, it now correctly sends the root URL from Rails to prevent errors with installations in subdirectories. 

## What are the relevant issue numbers?

Closes #23556

See merge request !7018

This MR removes AR before_validation callback in favor setter.

## Why was this MR needed?

Because setters is good practice to normalize model attributes instead AR callbacks. Because new object should be valid right after initialization. 
If it MR interested I can try to find other places where we can use setters.

See merge request !6763

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Moves `spec/mailers/shared/notify.rb` to `spec/support/notify_shared_examples.rb`

Closes #22609 

See merge request !6605

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

- Disable {project, group} members submit button if no users

  If no users are selected, the submit button should be disabled.

- Alert user when no users were added to {project, group}.

  When no users were selected for adding, an alert message is
  flashed that no users were added.

- Also, this commit adds a feedback when users were actually added to a
  project, in symmetry with how group members are handled.

Closes #22967, #23270.

This reverts commit c81ff152.

Fix reply-by-email not working due to queue name mismatch

See merge request !7068

Closes #23556

removes extra line for empty description

## What does this MR do?
This MR removes an odd line for empty description 
## Are there points in the code the reviewer needs to double check?
Not necessary
## Why was this MR needed?
Improve UX 
## Screenshots (if relevant)
**Before**
![ss__2016-10-19_at_11.04.45_PM](/uploads/12b376c772115c2e5eef2fe0c0d1992f/ss__2016-10-19_at_11.04.45_PM.png)
**After**
![edi](/uploads/89fea59ef5267974af4cbe1064dc521a/edi.png)
## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #23557 #23695

See merge request !7045

Document link syntax introduced by !5586.

See merge request !7049

* master: (22 commits)
  Fix status code expectation
  Stop clearing the database cache on rake cache:clear
  Fix error in generating labels
  Fix bug where e-mails were not being sent out via Sidekiq
  Fix documents and comments on Build API `scope`. #23146 #19131
  Re-organize queues to use for Sidekiq
  Fix wrong endpoint in api/users documentation, fix same typo in spec describe blocks
  Update CHANGELOG
  Fix object data to be sent to fetch analytics data
  Fixed compare ellipsis messing with layout
  Change "Group#web_url" to return "/groups/twitter" rather than "/twitter".
  fix font weight of project feature settings
  Add hover to trash icon in notes
  Ensure custom provider tab labels don't break layout.
  Fixed issue when images are loading it would push off the tabs
  Fixed issues with sticky mr tabs & sidebar
  Refactor and add new functionality to CI yaml reference
  Ignore external issues when bulk assigning issues to author of merge request.
  Changed gitlab-shell version to avoid warning when precompiling the assets.
  Grammar fixes in docs
  ...

Extract/mutate `params` in the `execute` method of the API services,
rather than in `initialize`.

- Pass `developers_and_merge` and `developers_can_push` in `params`
  instead of using keyword arguments.

- Refactor a slightly complex boolean check to a simple `nil?` check.

1. Don't have any EE-only code in CE. Ok to have CE-only code in EE.

2. Use `case` instead of `if/elsif`

1. Previously, we were not removing existing access levels before
   creating new ones. This is not a problem for EE, but _is_ for CE,
   since we restrict the number of access levels in CE to 1.

2. The correct approach is:

    CE -> delete all access levels before updating a protected branch
    EE -> delete developer access levels if "developers_can_{merge,push}" is switched off

3. The dispatch is performed by checking if a "length: 1" validation is
   present on the access levels or not.

4. Another source of problems was that we didn't put multiple queries in
   a transaction. If the `destroy_all` passes, but the `update` fails,
   we should have a rollback.

5. Modifying the API to provide users direct access to CRUD access
   levels will make things a lot simpler.

6. Create `create/update` services separately for this API, which
   perform the necessary data translation, before calling the regular
   `create/update` services. The translation code was getting too large
   for the API endpoint itself, so this move makes sense.

mail_room was configured to deliver mail to the `incoming_email`
queue while `EmailReceiveWorker` was reading the `email_receiver`
queue. Adds a migration that repeats the work of a previous
migration to ensure all mails that wound up in the old
queue get processed.

Closes #23689

After a project import, there's a chance that the UI checks the
branch count before the project has been imported. This change
causes more of the keys to be flushed after an import and forces
a rebuild of the repository cache.

Closes #13518

Fix error in generating labels

Attempting to generate default set of labels would result in
an error:

ArgumentError: wrong number of arguments (given 1, expected 0)

Closes #23649

See merge request !7055

Stop clearing the database cache on rake cache:clear

See merge request !7056

Fix documents and comments on Build API `scope`

Fixes #23146
Fixes #19131

See merge request !7044