On a merge request with over 1000 changed files, there were redundant
calls to blob_text_viewable?, which incurred about 7% of the time.

Improves #14775

If somehow a user attempted to accept a merge request that had
conflicts (e.g. the "Accept Merge Request" button or the MR itself was
not updated), `MergeService` did not properly detect that a conflict
occurred. It would assume that the MR went through without any issues
and close the MR as though everything was fine. This could cause
data loss if the source branch were removed.

Closes #20425

The method Ability.issues_readable_by_user takes a list of users and an
optional user and returns an Array of issues readable by said user. This
method in turn is used by
Banzai::ReferenceParser::IssueParser#nodes_visible_to_user so this
method no longer needs to get all the available abilities just to check
if a user has the "read_issue" ability.

To test this I benchmarked an issue with 222 comments on my development
environment. Using these changes the time spent in nodes_visible_to_user
was reduced from around 120 ms to around 40 ms.

1. Instantiate `ProtectedBranchesAccessSelect` from `dispatcher`

2. Use `can?(user, ...)` instead of `user.can?(...)`

3. Add `DOWNTIME` notes to all migrations added in !5081.

4. Add an explicit `down` method for migrations removing the
   `developers_can_push` and `developers_can_merge` columns, ensuring that
   the columns created (on rollback) have the appropriate defaults.

5. Remove duplicate CHANGELOG entries.

6. Blank lines after guard clauses.

1. Remove `master_or_greater?` and `developer_or_greater?` in favor of
   `max_member_access`, which is a lot nicer.

2. Remove a number of instances of `include Gitlab::Database::MigrationHelpers`
   in migrations that don't need this module. Also remove comments where
   not necessary.

3. Remove duplicate entry in CHANGELOG.

4. Move `ProtectedBranchAccessSelect` from Coffeescript to ES6.

5. Split the `set_access_levels!` method in two - one each for `merge` and
   `push` access levels.

 fix spec and added changelog

Before when you choose the way of `sort` instead it display the title correctly it was just apply the humanize helper in sort value.

E.g.

When you choose `Last updated` it should display the title `Last updated` instead of `Recently updated`. This fix makes this correctly displays the title.

Change the implementation of the `link_to` `filter_branches_path`

- Change the value of the `params[:sort]` in `link_to`. E.g. instead of using `'recently_updated'` is now using `sort_value_recently_updated`.

- Change the values of the case in the `branches_sorted_by` method for the values it receives in the `params[:sort]` that are: `nil`, `'name'`, `'updated_desc'`, `'updated_asc'`.

This reduces the overhead of the method instrumentation code primarily
by reducing the number of method calls. There are also some other small
optimisations such as not casting timing values to Floats (there's no
particular need for this), using Symbols for method call metric names,
and reducing the number of Hash lookups for instrumented methods.

The exact impact depends on the code being executed. For example, for a
method that's only called once the difference won't be very noticeable.
However, for methods that are called many times the difference can be
more significant.

For example, the loading time of a large commit
(nrclark/dummy_project@81ebdea5df2fb42e59257cb3eaad671a5c53ca36)
was reduced from around 19 seconds to around 15 seconds using these
changes.

In a PostReceive task with 697 commits (8.9 RC1 -> RC8), looking up
the commit author takes about 10% of the time. Caching this information
in RequestStore saves a few seconds from the overall processing time.

Improves #18663

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

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

Project and branch cache is expired when project is still
empty or new branch is created. develops tests accordingly
Signed-off-by: NRémy Coutable <remy@rymai.me>

Refactor spam validation to a concern that can be easily reused and improve legibility in `SpamCheckService`

NotesHelper#note_editable? and ProjectTeam#human_max_access currently
take about 16% of the load time of an issue page. This MR preloads
the maximum access level of users for all notes in issues and merge
requests with several queries instead of one per user and caches
the result in RequestStore.

A release's tag reference is just the name of the tag, not the entire
tag object.

This also fixes the tags index if a tag's message contains non-UTF8 byte
sequences.

We can't reuse the existing value of the format parameter, because on
the merge request page that's 'json', so the link would go to a JSON
file. We can't set it to HTML, because that adds '.html' the URL, which
breaks the compare view (and looks bad). Setting it to nil uses the
default format, which in all of these cases is HTML anyway.

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

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

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