- instead of using properties
- backward compatibility has to be kept for now

`Mentionable::ReferenceRegexes` used to define the following two
constants:

1. DEFAULT_PATTERN
2. EXTERNAL_PATTERN

These two constants were built using some of the class methods that
reside in this same module. In EE we redefine one of these methods by
using `prepend` at the start of the `ReferenceRegexes` module. This
poses a problem: we can not move the `prepend` to the end of the file,
because the constants later on depend on it.

To resolve this problem, this commit turns these constants into class
methods that memoize their results. This allows EE to redefine the
appropriate methods before these two class methods are used, in turn
allowing us to move the `prepend` to the end of the file.

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8198 for more
information.

Partially addresses #47424.

Douwe Maan authored 6 years ago and Mark Fletcher committed 6 years ago

Server Side Request Forgery in Services and Web Hooks

See merge request gitlab/gitlabhq!2337

Add OpenSSL::SSL::SSLError to rescue in JiraService & IssueTrackerService. This
will prevent an exception in production and instead display
a message to the user.

Code improvements, bug fixes, finish documentation and specs

This reverts commit 13e37a3e.

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

In 8278b763 the default behaviour of annotation
has changes, which was causing a lot of noise in diffs. We decided in #17382
that it is better to get rid of the whole annotate gem, and instead let people
look at schema.rb for the columns in a table.

Fixes: #17382

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

This greatly improves the performance of Project#external_issue_tracker
by moving most of the fields queried in Ruby to the database and letting
the database handle all logic. Prior to this change the process of
finding an external issue tracker was along the lines of the following:

1. Load all project services into memory.
2. Reduce the list to only services where "issue_tracker?" returns true
3. Reduce the list from step 2 to service where "default?" returns false
4. Find the first service where "activated?" returns true

This has to two big problems:

1. Loading all services into memory only to reduce the list down to a
   single item later on is a waste of memory (and slow timing wise).
2. Calling Array#select followed by Array#reject followed by Array#find
   allocates extra objects when this really isn't needed.

To work around this the following service fields have been moved to the
database (instead of being hardcoded):

* category
* default

This in turn means we can get the external issue tracker using the
following query:

    SELECT *
    FROM services
    WHERE active IS TRUE
    AND default IS FALSE
    AND category = 'issue_tracker'
    AND project_id = XXX
    LIMIT 1

This coupled with memoizing the result (just as before this commit)
greatly reduces the time it takes for Project#external_issue_tracker to
complete. The exact reduction depends on one's environment, but locally
the execution time is reduced from roughly 230 ms to only 2 ms (= a
reduction of almost 180x).

Fixes gitlab-org/gitlab-ce#10771