A lot of git operations were being repeated, for example, to build a url
    you would ask if the path was a Tree, which would call a recursive routine
    in Gitlab::Git::Tree#where, then ask if the path was a Blob, which would
    call a recursive routine at Gitlab::Git::Blob#find, making reference to
    the same git objects several times. Now we call Rugged::Tree#path, which
    allows us to determine the type of the path in one pass.

    Some other minor improvement added, like saving commonly used references
    instead of calculating them each time.

Previously we'd create a separate Metric instance for every method call
that would exceed the method call threshold. This is problematic because
it doesn't provide us with information to accurately get the _total_
execution time of a particular method. For example, if the method
"Foo#bar" was called 4 times with a runtime of ~10 milliseconds we'd end
up with 4 different Metric instances. If we were to then get the
average/95th percentile/etc of the timings this would be roughly 10
milliseconds. However, the _actual_ total time spent in this method
would be around 40 milliseconds.

To solve this problem we now create a single Metric instance per method.
This Metric instance contains the _total_ real/CPU time and the call
count for every instrumented method.

Updated shortcuts.png for docs

Updated CHANGELOG

Moved CHANGELOG entry

updated shortcut docs

- As todos are created/updated inside the TodoService
we repopulate the cache just there for both pending/done todos
- Todos as mark as done from the TodosController we update cache
there too
- All the added methods are kept in the User class for cohesion

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

Currently the RegexpError can be raised when processing next stage which leads to 500 in different places of code base.
This adds early check that regexps used in only and except are valid.

Limit push email diff size to 30 files or 150 KB, whichever comes first.

[ci skip]

Fixes #13980.

Besides when building the repository cache we cache 
those git counters too

This reverts commit 13e37a3e.

[ci skip]

[ci skip]

Previously, the dropdown toggle would default to "Select source branch",
this changes that so that it defaults to the branch name and if that
doesn't exist, it defaults to "Select source branch"