Add/document alpha_feature_available? method

This adds and documents an `alpha_feature_available?` method to groups
and projects, and also documents the existing `beta_feature_available?`
method.

doc/development/feature_flags/development.md

@@ -38,7 +38,7 @@ Feature.enabled?(:feature_flag, project, default_enabled: true)
 The [`Project#feature_available?`][project-fa],
 [`Namespace#feature_available?`][namespace-fa] (EE), and
 [`License.feature_available?`][license-fa] (EE) methods all implicitly check for
-a feature flag by the same name as the provided argument.
+a by default enabled feature flag with the same name as the provided argument.
 For example if a feature is license-gated, there's no need to add an additional
 explicit feature flag check since the flag will be checked as part of the
@@ -56,12 +56,19 @@ isn't gated by a License or Plan.
 unless the feature is explicitly disabled or limited to a percentage of users,
 the feature flag check will default to `true`.**
-As an example, if you were to ship the backend half of a feature behind a flag,
-you'd want to explicitly disable that flag until the frontend half is also ready
-to be shipped. To make sure this feature is disabled for both GitLab.com and
-self-managed instances you'd need to explicitly call `Feature.enabled?` method
-before the `feature_available` method. This ensures the feature_flag is defaulting
-to `false`.
+This is relevant when developing the feature using
+[several smaller merge requests](https://about.gitlab.com/handbook/values/#make-small-merge-requests), or when the feature is considered to be an
+[alpha or beta](https://about.gitlab.com/handbook/product/#alpha-beta-ga), and
+should not be available by default.
+
+As an example, if you were to ship the frontend half of a feature without the
+backend, you'd want to disable the feature entirely until the backend half is
+also ready to be shipped. To make sure this feature is disabled for both
+GitLab.com and self-managed instances, you should use the
+[`Namespace#alpha_feature_available?`](https://gitlab.com/gitlab-org/gitlab/blob/458749872f4a8f27abe8add930dbb958044cb926/ee/app/models/ee/namespace.rb#L113) or
+[`Namespace#beta_feature_available?`](https://gitlab.com/gitlab-org/gitlab/blob/458749872f4a8f27abe8add930dbb958044cb926/ee/app/models/ee/namespace.rb#L100-112)
+method, according to our [definitions](https://about.gitlab.com/handbook/product/#alpha-beta-ga). This ensures the feature is disabled unless the feature flag is
+_explicitly_ enabled.
 ## Feature groups

ee/app/models/ee/namespace.rb

@@ -112,6 +112,7 @@ module EE
       ::Feature.enabled?(feature, self) ||
         (::Feature.enabled?(feature) && feature_available?(feature))
     end
+    alias_method :alpha_feature_available?, :beta_feature_available?
     # Checks features (i.e. https://about.gitlab.com/pricing/) availabily
     # for a given Namespace plan. This method should consider ancestor groups

ee/app/models/ee/project.rb

@@ -297,6 +297,7 @@ module EE
       ::Feature.enabled?(feature, self) ||
         (::Feature.enabled?(feature) && feature_available?(feature))
     end
+    alias_method :alpha_feature_available?, :beta_feature_available?
     def push_audit_events_enabled?
       ::Feature.enabled?(:repository_push_audit_event, self)

ee/spec/models/group_spec.rb

@@ -607,8 +607,8 @@ describe Group do
     end
   end
-  describe '#beta_feature_available?' do
-    it_behaves_like 'an entity with beta feature support' do
+  describe '#alpha/beta_feature_available?' do
+    it_behaves_like 'an entity with alpha/beta feature support' do
       let(:entity) { group }
     end
   end

ee/spec/models/project_spec.rb

@@ -545,8 +545,8 @@ describe Project do
     end
   end
-  describe '#beta_feature_available?' do
-    it_behaves_like 'an entity with beta feature support' do
+  describe '#alpha/beta_feature_available?' do
+    it_behaves_like 'an entity with alpha/beta feature support' do
       let(:entity) { create(:project) }
     end
   end

ee/spec/support/shared_examples/models/alpha_beta_feature_support_shared_examples.rb

+# frozen_string_literal: true
+
+# This needs an `entity` object: Project or Group.
+RSpec.shared_examples 'an entity with alpha/beta feature support' do
+  where(level: %w[alpha beta])
+
+  with_them do
+    let(:method_name) { "#{level}_feature_available?" }
+
+    context 'when license does not allow it' do
+      before do
+        stub_licensed_features(insights: false)
+      end
+
+      context 'when the feature flag is disabled globally' do
+        before do
+          stub_feature_flags(insights: false)
+        end
+
+        it { expect(entity.public_send(method_name, :insights)).to be_falsy }
+      end
+
+      context 'when the feature flag is enabled globally' do
+        before do
+          stub_feature_flags(insights: true)
+        end
+
+        it { expect(entity.public_send(method_name, :insights)).to be_truthy }
+      end
+
+      context 'when the feature flag is enabled for the entity' do
+        before do
+          stub_feature_flags(insights: { enabled: true, thing: entity })
+        end
+
+        it { expect(entity.public_send(method_name, :insights)).to be_truthy }
+      end
+    end
+
+    context 'when license allows it' do
+      before do
+        stub_licensed_features(insights: true)
+      end
+
+      context 'when the feature flag is disabled globally' do
+        before do
+          stub_feature_flags(insights: false)
+        end
+
+        it { expect(entity.public_send(method_name, :insights)).to be_falsy }
+      end
+
+      context 'when the feature flag is enabled globally' do
+        before do
+          stub_feature_flags(insights: true)
+        end
+
+        it { expect(entity.public_send(method_name, :insights)).to be_truthy }
+      end
+
+      context 'when the feature flag is enabled for the entity' do
+        before do
+          stub_feature_flags(insights: { enabled: true, thing: entity })
+        end
+
+        it { expect(entity.public_send(method_name, :insights)).to be_truthy }
+      end
+    end
+  end
+end

ee/spec/support/shared_examples/models/beta_feature_support_shared_examples.rb

-# frozen_string_literal: true
-
-# This needs an `entity` object: Project or Group.
-RSpec.shared_examples 'an entity with beta feature support' do
-  context 'when license does not allow it' do
-    before do
-      stub_licensed_features(insights: false)
-    end
-
-    context 'when the feature flag is disabled globally' do
-      before do
-        stub_feature_flags(insights: false)
-      end
-
-      it { expect(entity.beta_feature_available?(:insights)).to be_falsy }
-    end
-
-    context 'when the feature flag is enabled globally' do
-      before do
-        stub_feature_flags(insights: true)
-      end
-
-      it { expect(entity.beta_feature_available?(:insights)).to be_truthy }
-    end
-
-    context 'when the feature flag is enabled for the entity' do
-      before do
-        stub_feature_flags(insights: { enabled: true, thing: entity })
-      end
-
-      it { expect(entity.beta_feature_available?(:insights)).to be_truthy }
-    end
-  end
-
-  context 'when license allows it' do
-    before do
-      stub_licensed_features(insights: true)
-    end
-
-    context 'when the feature flag is disabled globally' do
-      before do
-        stub_feature_flags(insights: false)
-      end
-
-      it { expect(entity.beta_feature_available?(:insights)).to be_falsy }
-    end
-
-    context 'when the feature flag is enabled globally' do
-      before do
-        stub_feature_flags(insights: true)
-      end
-
-      it { expect(entity.beta_feature_available?(:insights)).to be_truthy }
-    end
-
-    context 'when the feature flag is enabled for the entity' do
-      before do
-        stub_feature_flags(insights: { enabled: true, thing: entity })
-      end
-
-      it { expect(entity.beta_feature_available?(:insights)).to be_truthy }
-    end
-  end
-end