When we switched from a single-threaded application server (Unicorn) to
a multithreaded one (Puma), we did not realize that Puma often reaps
threads after a request is done and recreates them later. This makes the
thread-local cache ineffective, as the cache does not store anything
beyond the lifetime of the thread.

Since `ActiveSupport::Cache::MemoryStore` is thread-safe, we should be
able to switch the L1 cache for the feature flag list to use this to
reduce load on Redis.

Since read and write access is synchronized, this does have the side
effect of adding contention when feature flags are accessed.

We made a similar change in
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/26935, and this
seems to be working fine.

Discovered in
https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/9414

Remove database hits from Issue#moved? tests

See merge request gitlab-org/gitlab!27213

Enable Zeitwerk auto-loader

Closes #197345

See merge request gitlab-org/gitlab!20521

Move Issue#order_created_at_desc from EE to CE

Closes #210526

See merge request gitlab-org/gitlab!27325

Expose smaller Design Management design images in GraphQL

See merge request gitlab-org/gitlab!26947

Optimize AlertsService batch query

See merge request gitlab-org/gitlab!26982

Move "follow-up issue" below "getting majority"

See merge request gitlab-org/gitlab!27504

Convert audit logs date range field to use GitLab UI

See merge request gitlab-org/gitlab!26911

Updated the HAML file to reference the new app rather than the generic
event_filters HAML template.

A future MR will generalise this work into the shared templates

Optimize projects_service_active queries

See merge request gitlab-org/gitlab!27093

Add revision param validator

Closes #33766

See merge request gitlab-org/gitlab!26102

For new static checks, in order to avoid extra work authors
should create a follow-up issue _after_ the check got the majority.

This way authors can tick off the tasks top to bottom.

Merge branch '32085-fe-improve-documentation-and-static-checks-regarding-mutation-errors-conventions' into 'master'

Ensure all mutations have 'errors' field and a proper handler

See merge request gitlab-org/gitlab!27328

Resolve "Issue boards selector only shows first 100 boards"

See merge request gitlab-org/gitlab!27467

by adding an index and converting the
grouping to individual batch queries

Move Maskable concern to Ci namespace

See merge request gitlab-org/gitlab!27305

Optimize projects_mirrored_with_pipelines_enabled query

See merge request gitlab-org/gitlab!27110

Implements bare stages skeleton for jira importer

See merge request gitlab-org/gitlab!27118

Remove ci_file_based_cache feature flag

See merge request gitlab-org/gitlab!27406

Fix directory paths incorrectly encoding URLs

Closes #209075

See merge request gitlab-org/gitlab!27397

Upgrade unparser and parser gems

See merge request gitlab-org/gitlab!27381

Update issue link and quarantine spec

See merge request gitlab-org/gitlab!27476

Resolve "Fix showing only free namespaces when applying licenses"

Closes #208894

See merge request gitlab-org/gitlab!27356

Separate approval setting entities into own class files

See merge request gitlab-org/gitlab!27423

Recreate ancestor milestones when moving projects

See merge request gitlab-org/gitlab!27262

Jira importer will eventually import a lot of various data:
issues, comments, attachments, labels, custom fields, etc. We
can organize this data to be imported in stages thus parallelizing
the process. This change adds the initial structure of the
import process.

Add missing helpers in background migration

See merge request gitlab-org/gitlab!27483

Monitoring for Elasticsearch incremental updates buffer queue

See merge request gitlab-org/gitlab!27384

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/209075

Move HasVariable and NewHasVariable concerns to CI namespace

See merge request gitlab-org/gitlab!27306

HasVariable concern is only used by CI variable classes

Merge branch '211514-flaky-failure-in-qa-specs-features-browser_ui-3_create-repository-add_file_template_spec-rb' into 'master'

Resolve "Flaky failure in qa/specs/features/browser_ui/3_create/repository/add_file_template_spec.rb | Create File templates user adds LICENSE via file template Mozilla Public License 2.0"

Closes #211514

See merge request gitlab-org/gitlab!27439

Replace underscore/lodash in subscriptions

Closes #210269

See merge request gitlab-org/gitlab!27444

This metric is used to track the size of updates that need
to be synchronized to Elasticsearch. Since this is a custom queue and
we're not using Sidekiq we needed to implement our own custom monitoring
for it.

This MR just sets a gauge every minute in a cron worker which will
ultimately be available in Prometheus. Later we will build a chart for
this.

See https://gitlab.com/gitlab-org/gitlab/issues/207095

Migrate bot_type data to user_type column

Closes #208897

See merge request gitlab-org/gitlab!26981