Gracefully handle case when keep-around references are corrupted or exist already

We were seeing a number of error messages when attempting to create a keep-around ref:

1. Failed to create locked file `refs/keep-around/XYZ`: File exists
2. Failed to write reference `refs/keep-around/XYZ`: a reference with that name already exists.

I'm not sure how these happen, but I suspect when multiple workers attempt to write the same file we may have an issue. The force parameter should help ensure the file gets created,
as well as the rescues to prevent 500 Errors.

Rugged/libgit2 unfortunately does not allow you to delete or re-create a reference that has been corrupted, even with the force parameter. A truncated reference will stay that way until manual intervention.

Closes #20109

See merge request !5430
Signed-off-by: Rémy Coutable <remy@rymai.me>

Refactor repository storages documentation

Use detailed information on using the multiple repository storage feature

See merge request !5428
Signed-off-by: Rémy Coutable <remy@rymai.me>

Make Notify specs more robust by setting up assignee names

Closes #20121.

See merge request !5427

[ci skip]
Signed-off-by: Rémy Coutable <remy@rymai.me>

Refactor Slack service documentation



See merge request !5421

Move admin application settings to own path

Move existing documentation to its own `user/admin_area/settings` path.

See merge request !5420

Refactor protected branches documentation

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19832

See merge request !5419

Revert "Merge branch '17073-tagscontroller-index-is-terrible-response-time-goes-up-to-5-seconds' into 'master'"

This reverts commit be111259.

Add a spec for #20079

- This MR adds a spec for the fix for #20079 that was implemented in !5400.
- The spec is going in separately, just so the fix could go in as soon as possible.

See merge request !5414

Explain CI_PROJECT_NAMESPACE better

## What does this MR do?

Explain CI_PROJECT_NAMESPACE better by adding "The project namespace (username or groupname) that is currently being built".

## Are there points in the code the reviewer needs to double check?

Are `username` and `groupname` known words? We use it [here](http://docs.gitlab.com/ee/api/namespaces.html).

## Why was this MR needed?

Because `namespace` isn't a well known term.

## What are the relevant issue numbers?

## Screenshots (if relevant)


See merge request !5407

Simpler two queries than one JOIN with subquery

This is a follow up from !5347

Originally it was:

``` ruby
pipeline = pipelines.latest_successful_for(ref)
builds.where(pipeline: pipeline).latest.with_artifacts
```

However MySQL would complain that we can't use `IN` against a subquery which has `LIMIT`. Using `INNER JOIN` would be a workaround, however, doing that is too complicated in current version of Rails.

So let's just use two queries in this case.

Closes #14419

See merge request !5388

Merge branch '17073-tagscontroller-index-is-terrible-response-time-goes-up-to-5-seconds' into 'master'

Improve performance of tags controller

See merge request !5375

Fix a false positive where similar un-nested storage paths were reported as nested

Closes #19572

See merge request !5145

Change nav link snippet controller

Removes active Snippets nav link state for project-specific snippets

Closes #20046

See merge request !5410
(cherry picked from commit c53bd5a7)

Reduce min width of pipeline table

## What does this MR do?
Reduce min width of pipeline table

## Why was this MR needed?
The current min-width is based on the heavily populated pipelines page main table. This pipeline table doesn't have nearly as much information so can be collapsed down a lot further

![table](/uploads/895d2fb2f01383a841f973e918199f55/table.gif)
cc @markpundsack

See merge request !5409
(cherry picked from commit 95c4825a)

Avoid data-integrity issue when cleaning up repository archive cache

## What does this MR do?
Sets the default value for `repository_downloads_path` if someone has it configured incorrectly, and it points to the path where repositories are stored. It's also replace invocation of `find` with Ruby code that matches old cached files in a better, and safe way to avoid data-integrity issues.

## Why was this MR needed?
The `repository_downloads_path` is used by the `RepositoryArchiveCacheWorker` to remove outdated repository archives, if it points to the wrong directory can cause some data-integrity issue.

## What are the relevant issue numbers?
Closes #14222

See merge request !5285
(cherry picked from commit d2598f62)

Bump vmstat version to fix issues reporting on FreeBSD

Minor changes from 2.1.0 to 2.1.1:

https://github.com/threez/ruby-vmstat/commits/master

See merge request !5405
(cherry picked from commit 2cc3b893)

Don't drop in DropAndReaddHasExternalWikiInProjects

## What does this MR do?

This MR fixes the migration in question so it doesn't first drop and then re-add a column.

## Are there points in the code the reviewer needs to double check?

Not really.

## Why was this MR needed?

The old migration could lead to application errors as the column would temporarily not exist between the drop column and add column statements.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-com/infrastructure/issues/239

## Does this MR meet the acceptance criteria?

- [x] ~~[CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added~~
- [x] ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5402
(cherry picked from commit 2af769c3)

Don't use `params[:id]` while building `markdown_preview_path`.

- Closes #20079

See merge request !5400
(cherry picked from commit 2d7516ff)

UI bug fixes

Closes #20074
Closes #20094

Regression UI bug fixes
* Fix broken status icon on project page
* Center tooltip on empty state in pipeline
* Reduce max-width of commit title in pipeline so more fits in table
* Fixes firefox rendering (icons getting cut off)
* Fixes Safari rendering of SHA icon

See merge request !5383
(cherry picked from commit 0606b92c)

Fix migration to make it fast

## What does this MR do?

Changing the migration introduced in !5387 so that it's fast. The idea is that the content of the `projects.has_external_wiki` is currently wrong, so we can just drop and recreate the column.

## Does this MR meet the acceptance criteria?

- [x] No CHANGELOG needed
- Tests
  - [ ] All builds are passing
- [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 you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5394

Signed-off-by: Rémy Coutable <remy@rymai.me>

Cast duration to integer in `TimeHelper#time_interval_in_words`

Fixes #20055.

- [x] No CHANGELOG since it fixes a regression introduced in RC12.
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [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 you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5391

Fix emails on push for new and deleted branches

## What does this MR do?

Fix EmailsOnPushWorker when the push is either a new branch or a deleted branch.

## Are there points in the code the reviewer needs to double check?

Don't think so.

## Why was this MR needed? / What are the relevant issue numbers?

Closes #20061.

## Does this MR meet the acceptance criteria?

- ~~[CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added~~ (regression)
- ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [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 you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !5390

Show tooltip on GitLab export link in new project page

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19993

When the project path/name is not filled, we should show a tooltip in the `GitLab export` link, plus a flash message if the user still tries to click on it.

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5363

Hide project name in project activities

## What does this MR do?

- hide namespace and project name on project activity page

## Are there points in the code the reviewer needs to double check?

- did `.event_label` have any meaning?

## Why was this MR needed?

- all events on project activity page are from the same project, so the information was redundant

## What are the relevant issue numbers?

closes #18963

## Screenshots

### Before

![events-before](/uploads/76336e3f5cb08d4ef984df73c89aa90f/events-before.png)

### After

![events-after](/uploads/4a10718ed32960efc115d7854e5cad68/events-after.png)

![after-john-activity](/uploads/d9d151a829d8d32136525e8eb7ea04ad/after-john-activity.png)


See merge request !5068

Add image border in Markdown preview

## What does this MR do?

- add image border in Markdown preview like it is show after a comment is saved
- fix margin and shade of  `<hr>` in Markdown preview

## Are there points in the code the reviewer needs to double check?

Is `.md` the right class to use?

## Why was this MR needed?

The border was missing.

## What are the relevant issue numbers?

fixes #19652

## Screenshots

### Before

![before](/uploads/683e2af7278c33d29b2a1ae19d1136e3/before.png)

### After

![after](/uploads/07dcee531a5696303cb34b4a88357e8a/after.png)


See merge request !5162

Fixed dropdown enter key when searching

## What does this MR do?

When searching in a dropdown you can now just press the enter key to trigger a click on the first row rather than having to press the down key & then enter.

## What are the relevant issue numbers?

Closes #19741 

See merge request !5231

Refactor user authorization check for a single project to avoid querying all user projects

See merge request !5102

Warn on failure

## What does this MR do?

Adds styling and HTML for a `success_with_warnings` status in the MR widget. Unfinished as it needs some plumbing in the relevant CI controllers and models.

## Are there points in the code the reviewer needs to double check?

Not at the moment, though I think I'll probably need help getting this to work in the backend.

## What are the relevant issue numbers?

#17669 

## Screenshots (if relevant)

![Screen_Shot_2016-06-29_at_12.02.49_PM](/uploads/af4a915689633fe028f44bb34ae7a5b1/Screen_Shot_2016-06-29_at_12.02.49_PM.png)

## Does this MR meet the acceptance criteria?

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

cc: @ayufan 

See merge request !5004

Speed improvement for builds without DB

Only fetch the images which we are going to use. Speeds up the builds by about 30-45 seconds.

/cc @ayufan 

See merge request !4994

Added checks for migration downtime

This adds a set of checks that check/list which migrations require downtime (or not). It also comes with a CI task that fails should a migration not be tagged properly.

Fixes #14545

See merge request !4911

Merge branch '14284-allow-all-deploy-keys-to-be-retrieved-via-api-regardless-of-project-affiliation' into 'master'

Add /deploy_keys API to retrieve all deploy keys regardless of project affiliation

## What does this MR do?

Add /deploy_keys API to retrieve all deploy keys regardless of project affiliation

## Are there points in the code the reviewer needs to double check?

Is documentation clear?

## Why was this MR needed?

User request

## What are the relevant issue numbers?

#14284

See merge request !4426

Make Service.external_wikis return only active external wikis

Fixes #20067.

## Does this MR meet the acceptance criteria?

- [x] No CHANGELOG since it fixes a RC12 regression
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [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 you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5387

Merge branch '20041-gitlab-workhorse-version-should-be-update-to-0-7-8-in-our-documentation' into 'master'

Update gitlab-workhorse version to 0.7.8 in installation and update guides

Closes #20041.

See merge request !5385

Improve grammar of manual actions documentation

## What does this MR do?

Improve grammar of manual actions documentation

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

Because people like good grammar.

## What are the relevant issue numbers?

## Screenshots (if relevant)


See merge request !5382

Revert Content Security Policy

The secure-only cookies setting was causing an issue where the session was
constantly being lost in the development environment.

Revert "Merge branch 'csp-basics' into 'master'"

This reverts commit 9065f9c5, reversing
changes made to f0b446e5.

---

Revert "Merge branch 'remove-csp-sentry-reporting' into 'master'"

This reverts commit 79b02e40, reversing
changes made to f2cd21e8.

See merge request !5381

Remove flaky diff note tests for now

These will be replaced with better, more exhaustive specs by @lbennett based on the conversation in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5262.

See merge request !5379