Add latest changes from gitlab-org/gitlab@master

app/assets/javascripts/packages_and_registries/package_registry/components/details/npm_installation.vue

@@ -1,5 +1,5 @@
 <script>
-import { GlLink, GlSprintf } from '@gitlab/ui';
+import { GlLink, GlSprintf, GlFormRadioGroup } from '@gitlab/ui';
 import { s__ } from '~/locale';
 
 import InstallationTitle from '~/packages_and_registries/package_registry/components/details/installation_title.vue';
@@ -11,6 +11,8 @@ import {
   TRACKING_LABEL_CODE_INSTRUCTION,
   NPM_PACKAGE_MANAGER,
   YARN_PACKAGE_MANAGER,
+  PROJECT_PACKAGE_ENDPOINT_TYPE,
+  INSTANCE_PACKAGE_ENDPOINT_TYPE,
 } from '~/packages_and_registries/package_registry/constants';
 import CodeInstruction from '~/vue_shared/components/registry/code_instruction.vue';
 
@@ -21,8 +23,9 @@ export default {
     CodeInstruction,
     GlLink,
     GlSprintf,
+    GlFormRadioGroup,
   },
-  inject: ['npmHelpPath', 'npmPath'],
+  inject: ['npmHelpPath', 'npmPath', 'npmProjectPath'],
   props: {
     packageEntity: {
       type: Object,
@@ -32,6 +35,7 @@ export default {
   data() {
     return {
       instructionType: NPM_PACKAGE_MANAGER,
+      packageEndpointType: INSTANCE_PACKAGE_ENDPOINT_TYPE,
     };
   },
   computed: {
@@ -39,13 +43,13 @@ export default {
       return this.npmInstallationCommand(NPM_PACKAGE_MANAGER);
     },
     npmSetup() {
-      return this.npmSetupCommand(NPM_PACKAGE_MANAGER);
+      return this.npmSetupCommand(NPM_PACKAGE_MANAGER, this.packageEndpointType);
     },
     yarnCommand() {
       return this.npmInstallationCommand(YARN_PACKAGE_MANAGER);
     },
     yarnSetupCommand() {
-      return this.npmSetupCommand(YARN_PACKAGE_MANAGER);
+      return this.npmSetupCommand(YARN_PACKAGE_MANAGER, this.packageEndpointType);
     },
     showNpm() {
       return this.instructionType === NPM_PACKAGE_MANAGER;
@@ -58,14 +62,16 @@ export default {
 
       return `${instruction} ${this.packageEntity.name}`;
     },
-    npmSetupCommand(type) {
+    npmSetupCommand(type, endpointType) {
       const scope = this.packageEntity.name.substring(0, this.packageEntity.name.indexOf('/'));
+      const npmPathForEndpoint =
+        endpointType === INSTANCE_PACKAGE_ENDPOINT_TYPE ? this.npmPath : this.npmProjectPath;
 
       if (type === NPM_PACKAGE_MANAGER) {
-        return `echo ${scope}:registry=${this.npmPath}/ >> .npmrc`;
+        return `echo ${scope}:registry=${npmPathForEndpoint}/ >> .npmrc`;
       }
 
-      return `echo \\"${scope}:registry\\" \\"${this.npmPath}/\\" >> .yarnrc`;
+      return `echo \\"${scope}:registry\\" \\"${npmPathForEndpoint}/\\" >> .yarnrc`;
     },
   },
   packageManagers: {
@@ -87,6 +93,10 @@ export default {
     { value: NPM_PACKAGE_MANAGER, label: s__('PackageRegistry|Show NPM commands') },
     { value: YARN_PACKAGE_MANAGER, label: s__('PackageRegistry|Show Yarn commands') },
   ],
+  packageEndpointTypeOptions: [
+    { value: INSTANCE_PACKAGE_ENDPOINT_TYPE, text: s__('PackageRegistry|Instance-level') },
+    { value: PROJECT_PACKAGE_ENDPOINT_TYPE, text: s__('PackageRegistry|Project-level') },
+  ],
 };
 </script>
 
@@ -116,6 +126,12 @@ export default {
 
     <h3 class="gl-font-lg">{{ __('Registry setup') }}</h3>
 
+    <gl-form-radio-group
+      :options="$options.packageEndpointTypeOptions"
+      :checked="packageEndpointType"
+      @change="packageEndpointType = $event"
+    />
+
     <code-instruction
       v-if="showNpm"
       :instruction="npmSetup"

app/assets/javascripts/packages_and_registries/package_registry/constants.js

@@ -86,3 +86,6 @@ export const PACKAGE_PROCESSING_STATUS = 'PROCESSING';
 
 export const NPM_PACKAGE_MANAGER = 'npm';
 export const YARN_PACKAGE_MANAGER = 'yarn';
+
+export const PROJECT_PACKAGE_ENDPOINT_TYPE = 'project';
+export const INSTANCE_PACKAGE_ENDPOINT_TYPE = 'instance';

app/assets/javascripts/pages/shared/mount_runner_instructions.js

@@ -9,7 +9,12 @@ export function initInstallRunner(componentId = 'js-install-runner') {
   const installRunnerEl = document.getElementById(componentId);
 
   if (installRunnerEl) {
-    const defaultClient = createDefaultClient();
+    const defaultClient = createDefaultClient(
+      {},
+      {
+        assumeImmutableResults: true,
+      },
+    );
 
     const apolloProvider = new VueApollo({
       defaultClient,

app/assets/javascripts/releases/mount_show.js

@@ -6,7 +6,12 @@ import ReleaseShowApp from './components/app_show.vue';
 Vue.use(VueApollo);
 
 const apolloProvider = new VueApollo({
-  defaultClient: createDefaultClient(),
+  defaultClient: createDefaultClient(
+    {},
+    {
+      assumeImmutableResults: true,
+    },
+  ),
 });
 
 export default () => {

app/helpers/packages_helper.rb

@@ -70,6 +70,7 @@ module PackagesHelper
       can_delete: can?(current_user, :destroy_package, project).to_s,
       svg_path: image_path('illustrations/no-packages.svg'),
       npm_path: package_registry_instance_url(:npm),
+      npm_project_path: package_registry_project_url(project.id, :npm),
       npm_help_path: help_page_path('user/packages/npm_registry/index'),
       maven_path: package_registry_project_url(project.id, :maven),
       maven_help_path: help_page_path('user/packages/maven_repository/index'),

app/models/user.rb

@@ -2098,7 +2098,7 @@ class User < ApplicationRecord
   def check_username_format
     return if username.blank? || Mime::EXTENSION_LOOKUP.keys.none? { |type| username.end_with?(".#{type}") }
 
-    errors.add(:username, _('ending with a file extension is not allowed.'))
+    errors.add(:username, _('ending with a reserved file extension is not allowed.'))
   end
 
   def groups_with_developer_maintainer_project_access

doc/.vale/gitlab/Acronyms.yml

@@ -17,6 +17,7 @@ exceptions:
   - AJAX
   - ANSI
   - API
+  - APM
   - ARM
   - ARN
   - ASCII
@@ -24,6 +25,7 @@ exceptions:
   - BSD
   - CAS
   - CDN
+  - CIDR
   - CLI
   - CNA
   - CNAME

doc/administration/geo/replication/object_storage.md

@@ -73,7 +73,7 @@ GitLab does not currently support the case where both:
 ## Third-party replication services
 
 When using Amazon S3, you can use
-[CRR](https://docs.aws.amazon.com/AmazonS3/latest/dev/crr.html) to
+[Cross-Region Replication (CRR)](https://docs.aws.amazon.com/AmazonS3/latest/dev/crr.html) to
 have automatic replication between the bucket used by the **primary** site and
 the bucket used by **secondary** sites.
 

doc/user/clusters/management_project_template.md

@@ -91,10 +91,6 @@ the pipeline runs, Helmfile tries to either install or update your apps accordin
 cluster and Helm releases. If you change this attribute to `installed: false`, Helmfile tries try to uninstall this app
 from your cluster. [Read more](https://github.com/roboll/helmfile) about how Helmfile works.
 
-Furthermore, each app has an `applications/{app}/values.yaml` file (`applicaton/{app}/values.yaml.gotmpl` in case of GitLab Runner). This is the
-place where you can define default values for your app's Helm chart. Some apps already have defaults
-pre-defined by GitLab.
-
 ### Built-in applications
 
 The [built-in supported applications](https://gitlab.com/gitlab-org/project-templates/cluster-management/-/tree/master/applications) are:
@@ -110,3 +106,9 @@ The [built-in supported applications](https://gitlab.com/gitlab-org/project-temp
 - [Prometheus](../infrastructure/clusters/manage/management_project_applications/prometheus.md)
 - [Sentry](../infrastructure/clusters/manage/management_project_applications/sentry.md)
 - [Vault](../infrastructure/clusters/manage/management_project_applications/vault.md)
+
+#### How to customize your applications
+
+Each app has an `applications/{app}/values.yaml` file (`applicaton/{app}/values.yaml.gotmpl` in case of GitLab Runner). This is the
+place where you can define default values for your app's Helm chart. Some apps already have defaults
+pre-defined by GitLab.

doc/user/packages/npm_registry/index.md

@@ -370,13 +370,26 @@ in a JavaScript project. You can install a package from the scope of a project o
 
 If multiple packages have the same name and version, when you install a package, the most recently-published package is retrieved.
 
-1. Set the URL for scoped packages by running:
+1. Set the URL for scoped packages.
+
+   For [instance-level endpoints](#use-the-gitlab-endpoint-for-npm-packages) run:
 
    ```shell
    npm config set @foo:registry https://gitlab.example.com/api/v4/packages/npm/
    ```
 
-   Replace `@foo` with your scope.
+   - Replace `@foo` with your scope.
+   - Replace `gitlab.example.com` with your domain name.
+  
+   For [project-level endpoints](#use-the-gitlab-endpoint-for-npm-packages) run:
+
+   ```shell
+   npm config set @foo:registry https://gitlab.example.com/api/v4/projects/<your_project_id>/packages/npm/
+   ```
+
+   - Replace `@foo` with your scope.
+   - Replace `gitlab.example.com` with your domain name.
+   - Replace `<your_project_id>` with your project ID, found on the project's home page.
 
 1. Ensure [authentication](#authenticate-to-the-package-registry) is configured.
 

doc/user/project/clusters/serverless/index.md

@@ -282,7 +282,7 @@ Explanation of the fields used above:
 |-----------|-------------|
 | `name` | Indicates which provider is used to execute the `serverless.yml` file. In this case, the TriggerMesh middleware. |
 | `envs` | Includes the environment variables to be passed as part of function execution for **all** functions in the file, where `FOO` is the variable name and `BAR` are the variable contents. You may replace this with your own variables. |
-| `secrets` | Includes the contents of the Kubernetes secret as environment variables accessible to be passed as part of function execution for **all** functions in the file. The secrets are expected in INI format. |
+| `secrets` | Includes the contents of the Kubernetes secret as environment variables accessible to be passed as part of function execution for **all** functions in the file. The secrets are expected in `INI` format. |
 
 ### `functions`
 
@@ -296,7 +296,7 @@ subsequent lines contain the function attributes.
 | `runtime` (optional)| The runtime to be used to execute the function. This can be a runtime alias (see [Runtime aliases](#runtime-aliases)), or it can be a full URL to a custom runtime repository. When the runtime is not specified, we assume that `Dockerfile` is present in the function directory specified by `source`. |
 | `description` | A short description of the function. |
 | `envs` | Sets an environment variable for the specific function only. |
-| `secrets` | Includes the contents of the Kubernetes secret as environment variables accessible to be passed as part of function execution for the specific function only. The secrets are expected in INI format. |
+| `secrets` | Includes the contents of the Kubernetes secret as environment variables accessible to be passed as part of function execution for the specific function only. The secrets are expected in `INI` format. |
 
 ### Deployment
 

lib/gitlab/database/load_balancing/load_balancer.rb

@@ -235,7 +235,7 @@ module Gitlab
             @configuration.model.connection_specification_name,
             role: ActiveRecord::Base.writing_role,
             shard: ActiveRecord::Base.default_shard
-          )
+          ) || raise(::ActiveRecord::ConnectionNotEstablished)
         end
 
         private

locale/gitlab.pot

@@ -24145,6 +24145,9 @@ msgstr ""
 msgid "PackageRegistry|Install package version"
 msgstr ""
 
+msgid "PackageRegistry|Instance-level"
+msgstr ""
+
 msgid "PackageRegistry|Invalid Package: failed metadata extraction"
 msgstr ""
 
@@ -24190,6 +24193,9 @@ msgstr ""
 msgid "PackageRegistry|Pip Command"
 msgstr ""
 
+msgid "PackageRegistry|Project-level"
+msgstr ""
+
 msgid "PackageRegistry|Publish and share packages for a variety of common package managers. %{docLinkStart}More information%{docLinkEnd}"
 msgstr ""
 
@@ -39909,7 +39915,7 @@ msgstr ""
 msgid "encrypted: needs to be a :required, :optional or :migrating!"
 msgstr ""
 
-msgid "ending with a file extension is not allowed."
+msgid "ending with a reserved file extension is not allowed."
 msgstr ""
 
 msgid "entries cannot be larger than 255 characters"

spec/frontend/packages_and_registries/package_registry/components/details/__snapshots__/npm_installation_spec.js.snap

@@ -21,6 +21,15 @@ exports[`NpmInstallation renders all the messages 1`] = `
     Registry setup
   </h3>
    
+  <gl-form-radio-group-stub
+    checked="instance"
+    disabledfield="disabled"
+    htmlfield="html"
+    options="[object Object],[object Object]"
+    textfield="text"
+    valuefield="value"
+  />
+   
   <code-instruction-stub
     copytext="Copy npm setup command"
     instruction="echo @gitlab-org:registry=npmPath/ >> .npmrc"

spec/frontend/packages_and_registries/package_registry/components/details/npm_installation_spec.js

@@ -1,3 +1,4 @@
+import { GlFormRadioGroup } from '@gitlab/ui';
 import { nextTick } from 'vue';
 import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
 
@@ -12,6 +13,8 @@ import {
   PACKAGE_TYPE_NPM,
   NPM_PACKAGE_MANAGER,
   YARN_PACKAGE_MANAGER,
+  PROJECT_PACKAGE_ENDPOINT_TYPE,
+  INSTANCE_PACKAGE_ENDPOINT_TYPE,
 } from '~/packages_and_registries/package_registry/constants';
 import CodeInstructions from '~/vue_shared/components/registry/code_instruction.vue';
 
@@ -25,12 +28,14 @@ describe('NpmInstallation', () => {
 
   const findCodeInstructions = () => wrapper.findAllComponents(CodeInstructions);
   const findInstallationTitle = () => wrapper.findComponent(InstallationTitle);
+  const findEndPointTypeSector = () => wrapper.findComponent(GlFormRadioGroup);
 
   function createComponent({ data = {} } = {}) {
     wrapper = shallowMountExtended(NpmInstallation, {
       provide: {
         npmHelpPath: 'npmHelpPath',
         npmPath: 'npmPath',
+        npmProjectPath: 'npmProjectPath',
       },
       propsData: {
         packageEntity,
@@ -53,6 +58,19 @@ describe('NpmInstallation', () => {
     expect(wrapper.element).toMatchSnapshot();
   });
 
+  describe('endpoint type selector', () => {
+    it('has the endpoint type selector', () => {
+      expect(findEndPointTypeSector().exists()).toBe(true);
+      expect(findEndPointTypeSector().vm.$attrs.checked).toBe(INSTANCE_PACKAGE_ENDPOINT_TYPE);
+      expect(findEndPointTypeSector().props()).toMatchObject({
+        options: [
+          { value: INSTANCE_PACKAGE_ENDPOINT_TYPE, text: 'Instance-level' },
+          { value: PROJECT_PACKAGE_ENDPOINT_TYPE, text: 'Project-level' },
+        ],
+      });
+    });
+  });
+
   describe('install command switch', () => {
     it('has the installation title component', () => {
       expect(findInstallationTitle().exists()).toBe(true);
@@ -96,6 +114,28 @@ describe('NpmInstallation', () => {
         trackingAction: TRACKING_ACTION_COPY_NPM_SETUP_COMMAND,
       });
     });
+
+    it('renders the correct setup command for different endpoint types', async () => {
+      findEndPointTypeSector().vm.$emit('change', PROJECT_PACKAGE_ENDPOINT_TYPE);
+
+      await nextTick();
+
+      expect(findCodeInstructions().at(1).props()).toMatchObject({
+        instruction: `echo @gitlab-org:registry=npmProjectPath/ >> .npmrc`,
+        multiline: false,
+        trackingAction: TRACKING_ACTION_COPY_NPM_SETUP_COMMAND,
+      });
+
+      findEndPointTypeSector().vm.$emit('change', INSTANCE_PACKAGE_ENDPOINT_TYPE);
+
+      await nextTick();
+
+      expect(findCodeInstructions().at(1).props()).toMatchObject({
+        instruction: `echo @gitlab-org:registry=npmPath/ >> .npmrc`,
+        multiline: false,
+        trackingAction: TRACKING_ACTION_COPY_NPM_SETUP_COMMAND,
+      });
+    });
   });
 
   describe('yarn', () => {
@@ -118,5 +158,27 @@ describe('NpmInstallation', () => {
         trackingAction: TRACKING_ACTION_COPY_YARN_SETUP_COMMAND,
       });
     });
+
+    it('renders the correct setup command for different endpoint types', async () => {
+      findEndPointTypeSector().vm.$emit('change', PROJECT_PACKAGE_ENDPOINT_TYPE);
+
+      await nextTick();
+
+      expect(findCodeInstructions().at(1).props()).toMatchObject({
+        instruction: `echo \\"@gitlab-org:registry\\" \\"npmProjectPath/\\" >> .yarnrc`,
+        multiline: false,
+        trackingAction: TRACKING_ACTION_COPY_YARN_SETUP_COMMAND,
+      });
+
+      findEndPointTypeSector().vm.$emit('change', INSTANCE_PACKAGE_ENDPOINT_TYPE);
+
+      await nextTick();
+
+      expect(findCodeInstructions().at(1).props()).toMatchObject({
+        instruction: 'echo \\"@gitlab-org:registry\\" \\"npmPath/\\" >> .yarnrc',
+        multiline: false,
+        trackingAction: TRACKING_ACTION_COPY_YARN_SETUP_COMMAND,
+      });
+    });
   });
 });

spec/initializers/database_config_spec.rb

@@ -2,19 +2,11 @@
 
 require 'spec_helper'
 
-RSpec.describe 'Database config initializer' do
+RSpec.describe 'Database config initializer', :reestablished_active_record_base do
   subject do
     load Rails.root.join('config/initializers/database_config.rb')
   end
 
-  around do |example|
-    original_config = ActiveRecord::Base.connection_db_config
-
-    example.run
-
-    ActiveRecord::Base.establish_connection(original_config)
-  end
-
   before do
     allow(Gitlab::Runtime).to receive(:max_threads).and_return(max_threads)
   end

spec/lib/gitlab/database/bulk_update_spec.rb

@@ -91,45 +91,38 @@ RSpec.describe Gitlab::Database::BulkUpdate do
       .to eq(['MR a', 'Issue a', 'Issue b'])
   end
 
-  shared_examples 'basic functionality' do
-    it 'sets multiple values' do
-      create_default(:user)
-      create_default(:project)
+  context 'validates prepared_statements support', :reestablished_active_record_base do
+    using RSpec::Parameterized::TableSyntax
 
-      i_a, i_b = create_list(:issue, 2)
-
-      mapping = {
-        i_a => { title: 'Issue a' },
-        i_b => { title: 'Issue b' }
-      }
-
-      described_class.execute(%i[title], mapping)
-
-      expect([i_a, i_b].map { |x| x.reset.title })
-        .to eq(['Issue a', 'Issue b'])
+    where(:prepared_statements) do
+      [false, true]
     end
-  end
 
-  include_examples 'basic functionality'
-
-  context 'when prepared statements are configured differently to the normal test environment' do
     before do
-      klass = Class.new(ActiveRecord::Base) do
-        def self.abstract_class?
-          true # So it gets its own connection
-        end
-      end
+      configuration_hash = ActiveRecord::Base.connection_db_config.configuration_hash
 
-      stub_const('ActiveRecordBasePreparedStatementsInverted', klass)
-
-      c = ActiveRecord::Base.retrieve_connection.instance_variable_get(:@config)
-      inverted = c.merge(prepared_statements: !ActiveRecord::Base.connection.prepared_statements)
-      ActiveRecordBasePreparedStatementsInverted.establish_connection(inverted)
-
-      allow(ActiveRecord::Base).to receive(:connection_specification_name)
-        .and_return(ActiveRecordBasePreparedStatementsInverted.connection_specification_name)
+      ActiveRecord::Base.establish_connection(
+        configuration_hash.merge(prepared_statements: prepared_statements)
+      )
     end
 
-    include_examples 'basic functionality'
+    with_them do
+      it 'sets multiple values' do
+        create_default(:user)
+        create_default(:project)
+
+        i_a, i_b = create_list(:issue, 2)
+
+        mapping = {
+          i_a => { title: 'Issue a' },
+          i_b => { title: 'Issue b' }
+        }
+
+        described_class.execute(%i[title], mapping)
+
+        expect([i_a, i_b].map { |x| x.reset.title })
+          .to eq(['Issue a', 'Issue b'])
+      end
+    end
   end
 end

spec/lib/gitlab/database/connection_spec.rb

@@ -126,15 +126,7 @@ RSpec.describe Gitlab::Database::Connection do
     end
   end
 
-  describe '#disable_prepared_statements' do
-    around do |example|
-      original_config = connection.scope.connection.pool.db_config
-
-      example.run
-
-      connection.scope.establish_connection(original_config)
-    end
-
+  describe '#disable_prepared_statements', :reestablished_active_record_base do
     it 'disables prepared statements' do
       connection.scope.establish_connection(
         ::Gitlab::Database.main.config.merge(prepared_statements: true)

spec/lib/gitlab/database/postgresql_adapter/force_disconnectable_mixin_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-RSpec.describe Gitlab::Database::PostgresqlAdapter::ForceDisconnectableMixin do
+RSpec.describe Gitlab::Database::PostgresqlAdapter::ForceDisconnectableMixin, :reestablished_active_record_base do
   describe 'checking in a connection to the pool' do
     let(:model) do
       Class.new(ActiveRecord::Base) do

spec/lib/gitlab/database/schema_migrations/context_spec.rb

@@ -23,7 +23,7 @@ RSpec.describe Gitlab::Database::SchemaMigrations::Context do
       end
     end
 
-    context 'multiple databases' do
+    context 'multiple databases', :reestablished_active_record_base do
       let(:connection_class) do
         Class.new(::ApplicationRecord) do
           self.abstract_class = true
@@ -34,8 +34,6 @@ RSpec.describe Gitlab::Database::SchemaMigrations::Context do
         end
       end
 
-      let(:configuration_overrides) { {} }
-
       before do
         connection_class.establish_connection(
           ActiveRecord::Base

spec/models/user_spec.rb

@@ -401,7 +401,7 @@ RSpec.describe User do
           user = build(:user, username: "test.#{type}")
 
           expect(user).not_to be_valid
-          expect(user.errors.full_messages).to include('Username ending with a file extension is not allowed.')
+          expect(user.errors.full_messages).to include('Username ending with a reserved file extension is not allowed.')
           expect(build(:user, username: "test#{type}")).to be_valid
         end
       end

spec/support/database/multiple_databases.rb

@@ -5,5 +5,57 @@ module Database
     def skip_if_multiple_databases_not_setup
       skip 'Skipping because multiple databases not set up' unless Gitlab::Database.has_config?(:ci)
     end
+
+    # The usage of this method switches temporarily used `connection_handler`
+    # allowing full manipulation of ActiveRecord::Base connections without
+    # having side effects like:
+    # - misaligned transactions since this is managed by `BeforeAllAdapter`
+    # - removal of primary connections
+    #
+    # The execution within a block ensures safe cleanup of all allocated resources.
+    #
+    # rubocop:disable Database/MultipleDatabases
+    def with_reestablished_active_record_base(reconnect: true)
+      connection_classes = ActiveRecord::Base.connection_handler.connection_pool_names.map(&:constantize).to_h do |klass|
+        [klass, klass.connection_db_config]
+      end
+
+      original_handler = ActiveRecord::Base.connection_handler
+      new_handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
+      ActiveRecord::Base.connection_handler = new_handler
+
+      if reconnect
+        connection_classes.each { |klass, db_config| klass.establish_connection(db_config) }
+      end
+
+      yield
+    ensure
+      ActiveRecord::Base.connection_handler = original_handler
+      new_handler&.clear_all_connections!
+    end
+    # rubocop:enable Database/MultipleDatabases
+  end
+
+  module ActiveRecordBaseEstablishConnection
+    def establish_connection(*args)
+      # rubocop:disable Database/MultipleDatabases
+      if connected? && connection&.transaction_open? && ActiveRecord::Base.connection_handler == ActiveRecord::Base.default_connection_handler
+        raise "Cannot re-establish '#{self}.establish_connection' within an open transaction (#{connection&.open_transactions.to_i}). " \
+          "Use `with_reestablished_active_record_base` instead or add `:reestablished_active_record_base` to rspec context."
+      end
+      # rubocop:enable Database/MultipleDatabases
+
+      super
+    end
   end
 end
+
+RSpec.configure do |config|
+  config.around(:each, :reestablished_active_record_base) do |example|
+    with_reestablished_active_record_base(reconnect: example.metadata.fetch(:reconnect, true)) do
+      example.run
+    end
+  end
+end
+
+ActiveRecord::Base.singleton_class.prepend(::Database::ActiveRecordBaseEstablishConnection) # rubocop:disable Database/MultipleDatabases

spec/support_specs/database/multiple_databases_spec.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Database::MultipleDatabases' do
+  describe '.with_reestablished_active_record_base' do
+    context 'when doing establish_connection' do
+      context 'on ActiveRecord::Base' do
+        it 'raises exception' do
+          expect { ActiveRecord::Base.establish_connection(:main) }.to raise_error /Cannot re-establish/
+        end
+
+        context 'when using with_reestablished_active_record_base' do
+          it 'does not raise exception' do
+            with_reestablished_active_record_base do
+              expect { ActiveRecord::Base.establish_connection(:main) }.not_to raise_error
+            end
+          end
+        end
+      end
+
+      context 'on Ci::CiDatabaseRecord' do
+        before do
+          skip_if_multiple_databases_not_setup
+        end
+
+        it 'raises exception' do
+          expect { Ci::CiDatabaseRecord.establish_connection(:ci) }.to raise_error /Cannot re-establish/
+        end
+
+        context 'when using with_reestablished_active_record_base' do
+          it 'does not raise exception' do
+            with_reestablished_active_record_base do
+              expect { Ci::CiDatabaseRecord.establish_connection(:main) }.not_to raise_error
+            end
+          end
+        end
+      end
+    end
+
+    context 'when trying to access connection' do
+      context 'when reconnect is true' do
+        it 'does not raise exception' do
+          with_reestablished_active_record_base(reconnect: true) do
+            expect { ActiveRecord::Base.connection.execute("SELECT 1") }.not_to raise_error # rubocop:disable Database/MultipleDatabases
+          end
+        end
+      end
+
+      context 'when reconnect is false' do
+        it 'does raise exception' do
+          with_reestablished_active_record_base(reconnect: false) do
+            expect { ActiveRecord::Base.connection.execute("SELECT 1") }.to raise_error(ActiveRecord::ConnectionNotEstablished) # rubocop:disable Database/MultipleDatabases
+          end
+        end
+      end
+    end
+  end
+end