This optimises searching for users when using queries consisting out of
one or two characters such as "ab". We optimise such cases by searching
for `LOWER(name)` and `LOWER(username)` instead of using `ILIKE`. Using
`LOWER` produces a _much_ better performing query.

For example, when searching for all users matching the term "a" we'd
produce the following plan:

     Limit  (cost=637.69..637.74 rows=20 width=805) (actual time=41.983..41.995 rows=20 loops=1)
       Buffers: shared hit=8330
       ->  Sort  (cost=637.69..638.61 rows=368 width=805) (actual time=41.982..41.990 rows=20 loops=1)
             Sort Key: (CASE WHEN ((name)::text = 'a'::text) THEN 0 WHEN ((username)::text = 'a'::text) THEN 1 WHEN ((email)::text = 'a'::text) THEN 2 ELSE 3 END), name
             Sort Method: top-N heapsort  Memory: 35kB
             Buffers: shared hit=8330
             ->  Bitmap Heap Scan on users  (cost=75.47..627.89 rows=368 width=805) (actual time=9.452..41.305 rows=277 loops=1)
                   Recheck Cond: (((name)::text ~~* 'a'::text) OR ((username)::text ~~* 'a'::text) OR ((email)::text = 'a'::text))
                   Rows Removed by Index Recheck: 7601
                   Heap Blocks: exact=7636
                   Buffers: shared hit=8327
                   ->  BitmapOr  (cost=75.47..75.47 rows=368 width=0) (actual time=8.290..8.290 rows=0 loops=1)
                         Buffers: shared hit=691
                         ->  Bitmap Index Scan on index_users_on_name_trigram  (cost=0.00..38.85 rows=180 width=0) (actual time=4.369..4.369 rows=4071 loops=1)
                               Index Cond: ((name)::text ~~* 'a'::text)
                               Buffers: shared hit=360
                         ->  Bitmap Index Scan on index_users_on_username_trigram  (cost=0.00..34.41 rows=188 width=0) (actual time=3.896..3.896 rows=4140 loops=1)
                               Index Cond: ((username)::text ~~* 'a'::text)
                               Buffers: shared hit=328
                         ->  Bitmap Index Scan on users_email_key  (cost=0.00..1.94 rows=1 width=0) (actual time=0.022..0.022 rows=0 loops=1)
                               Index Cond: ((email)::text = 'a'::text)
                               Buffers: shared hit=3
     Planning time: 3.912 ms
     Execution time: 42.171 ms

With the changes in this commit we now produce the following plan
instead:

     Limit  (cost=13257.48..13257.53 rows=20 width=805) (actual time=1.567..1.579 rows=20 loops=1)
       Buffers: shared hit=287
       ->  Sort  (cost=13257.48..13280.93 rows=9379 width=805) (actual time=1.567..1.572 rows=20 loops=1)
             Sort Key: (CASE WHEN ((name)::text = 'a'::text) THEN 0 WHEN ((username)::text = 'a'::text) THEN 1 WHEN ((email)::text = 'a'::text) THEN 2 ELSE 3 END), name
             Sort Method: top-N heapsort  Memory: 35kB
             Buffers: shared hit=287
             ->  Bitmap Heap Scan on users  (cost=135.66..13007.91 rows=9379 width=805) (actual time=0.194..1.107 rows=277 loops=1)
                   Recheck Cond: ((lower((name)::text) = 'a'::text) OR (lower((username)::text) = 'a'::text) OR ((email)::text = 'a'::text))
                   Heap Blocks: exact=277
                   Buffers: shared hit=287
                   ->  BitmapOr  (cost=135.66..135.66 rows=9379 width=0) (actual time=0.152..0.152 rows=0 loops=1)
                         Buffers: shared hit=10
                         ->  Bitmap Index Scan on yorick_test_users  (cost=0.00..124.75 rows=9377 width=0) (actual time=0.101..0.101 rows=277 loops=1)
                               Index Cond: (lower((name)::text) = 'a'::text)
                               Buffers: shared hit=4
                         ->  Bitmap Index Scan on index_on_users_lower_username  (cost=0.00..1.94 rows=1 width=0) (actual time=0.035..0.035 rows=1 loops=1)
                               Index Cond: (lower((username)::text) = 'a'::text)
                               Buffers: shared hit=3
                         ->  Bitmap Index Scan on users_email_key  (cost=0.00..1.94 rows=1 width=0) (actual time=0.014..0.014 rows=0 loops=1)
                               Index Cond: ((email)::text = 'a'::text)
                               Buffers: shared hit=3
     Planning time: 0.303 ms
     Execution time: 1.687 ms

Here we can see the new query is 25 times faster compared to the old
query.

The frontend code doesn't use this so there's no practical point in
supporting this. We also hardcode the limit to 20 so users can no longer
request their own limit, which could overload the database (depending on
any upper bounds perhaps enforced by Kaminari).

We can instead just use a UNION. This removes the need for plucking
hundreds if not thousands of IDs into memory when a project has many
members.

Use dynamic imports in dispatcher (Part 3)

See merge request gitlab-org/gitlab-ce!17277

Add link to project visibility settings in push to create project docs

See merge request gitlab-org/gitlab-ce!17292

Docs milestones refactor

See merge request gitlab-org/gitlab-ce!17247

Docs: search/replace "Enterprise Edition" and adjust when applicable

See merge request gitlab-org/gitlab-ce!17161

Fix 500 error when loading an invalid upload URL

Closes gitlab-ee#4998

See merge request gitlab-org/gitlab-ce!17267

Revert "Merge branch 'tc-info-version-check' into 'master'"

See merge request gitlab-org/gitlab-ce!17269

Resolve "document where user clone/fetch activity appears in the logs"

Closes #43416

See merge request gitlab-org/gitlab-ce!17227

Harmonize CE and EE JS code

See merge request gitlab-org/gitlab-ce!17264

Resolve "ActionView::Template::Error: 366..524 out of range"

Closes #42332

See merge request gitlab-org/gitlab-ce!17262

Resolve "Spec failure: spec/features/users_spec.rb"

Closes #43495

See merge request gitlab-org/gitlab-ce!17289

Backport of Webpack auto include for EE imports

See merge request gitlab-org/gitlab-ce!17282

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

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

Rugged sometimes chops a context line in between bytes, resulting in the context
line having an invalid encoding: https://github.com/libgit2/rugged/issues/716

When that happens, we will try to detect the encoding for the diff, and
sometimes we'll get it wrong. If that difference in encoding results in a
difference in string lengths between the diff and the underlying blobs, we'd
fail to highlight any inline diffs, and return a 500 status to the user.

As we're using the underlying blobs, the encoding is 'correct' anyway, so if the
string range is invalid, we can just discard the inline diff highlighting. We
still report to Sentry to ensure that we can investigate further in future.

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

Fix squash with renamed files

Closes gitlab-ee#4975

See merge request gitlab-org/gitlab-ce!17216

Allow branchnames to be named the same as the commit it points to

See merge request gitlab-org/gitlab-ce!17231

Format markdown.md to comply with what it describes.

See merge request gitlab-org/gitlab-ce!17284

[ci skip]

Add more detail to the proofreader process

See merge request gitlab-org/gitlab-ce!17279

Resolve "Followup to New design for cancel/stop pipeline confirmation"

Closes #42886

See merge request gitlab-org/gitlab-ce!17106

[CE] Incorporate Gitaly's RepositoryService.IsSquashInProgress RPC

See merge request gitlab-org/gitlab-ce!17002

Resolve "Controller Projects::PipelinesController#show executes more than 100 SQL queries"

Closes #43134

See merge request gitlab-org/gitlab-ce!17168

When the text says "here are two spaces to force a line break"
there really should be two spaces to force a line break.

Fix repo existence check in GitAccessWiki

Closes #43385 and gitlab-com/infrastructure#3734

See merge request gitlab-org/gitlab-ce!17268