Fix cloning Wiki repositories via HTTP
Cloning a project Wiki over HTTP would end up cloning the main repository
since the .wiki extension was being stripped.
Closes#3106
See merge request !1676
Redirect to a default path if HTTP_REFERER is not set
Safari 9.0 does not yet honor the HTML5 `origin-when-cross-origin` mode,
and it's possible load balancers/proxies strip the HTTP_REFERER from
the request header. In these cases, default to some default path.
Closes#3122
Closes https://github.com/gitlabhq/gitlabhq/issues/9731
See merge request !1646
Separate rendering of Markdown reference links from redacting those the user doesn't have access to and extracting referenced objects
Related: !1014
See merge request !1090
Add a system note and update relevant merge requests when a branch is deleted or re-added
If a branch is deleted with an open merge request, amended offline, and then pushed again,
GitLab doesn't bother to update the merge request even though the last commit ID and/or
code may have changed. This MR ensures that each push will update any relevant merge
requests and adds a system note if this happens as well.
The new messages look like:

Closes#2926
See merge request !1601
Improve invalidation of stored service password if the endpoint URL is changed (V2)
New version of !1583, using the same failproof logic but this time mirroring the name and behaviour of the change-tracking methods of ActiveModel::Dirty in order to make it clearer and more natural.
Added more tests to clarify the expected behaviour.
This is an alternative to !1594
/cc @vsizov @rspeicher
See merge request !1600
Improve User.by_login performance
This greatly speeds up the performance of `User.by_login`. I adopted some changes from @haynes in this patch, the credits go to him for coming up with those originally.
Fixes#2341
See merge request !1545
Let gitlab-git-http-server handle archive downloads
This change relies on changes in gitlab_git and gitlab-git-http-server.
fixes#2429
See merge request !1548
Fix error preventing displaying of commit data for a directory with a leading dot
Directories with leading dots erroneously get rejected by the route controller if git
ref regex is used in constraints. This prevents commit data from being loaded. The regex verification is now done in controller.
Closes https://github.com/gitlabhq/gitlabhq/issues/8763
See merge request !1574
By comparing objects in Ruby we can greatly improve the performance of
this method. In the worst case (should no data be eager loaded) this
will run the same amount of queries as before, in the best case (when
data _is_ eager loadeD) it requires no queries at all.
The added benchmark used to produce around 273 iterations per second.
With this commit this has been increased to almost 40 000 iterations per
second: a speedup of roughly 145 times.
Combined with eager loading Note associations this results in about 30
queries less when viewing a single issue, this in turn cuts down the
loading time by 30-40%.
Performance is improved in two steps:
1. On PostgreSQL an expression index is used for checking lower(email)
and lower(username).
2. The check to determine if we're searching for a username or Email is
moved to Ruby. Thanks to @haynes for suggesting and writing the
initial implementation of this.
Moving the check to Ruby makes this method an additional 1.5 times
faster compared to doing the check in the SQL query.
With performance being improved I've now also tweaked the amount of
iterations required by the User.by_login benchmark. This method now runs
between 900 and 1000 iterations per second.
Add a few predefined variables to CI builds
This adds CI_BUILD_TAG, CI_BUILD_STAGE, CI_BUILD_NAME and CI_BUILD_TRIGGERED to build environment.
This change is based on: !1530
See merge request !1572