Remove redundant validates_unique where DB unique index already exists (#4930)

* feat: validate_unique removed

- Model's that already has uniqueness constraint on db level are refactored. sequel validate_unique method removed from list.

* feat: around_save added for existing unique index for service_plan

* feat: around_save added for existing unique index for service_plan_visibility

* feat: around_save added for existing unique index for service_dashboard_client model

* feat: around_save added for existing unique index for feature_flag model

* feat: around_save added for existing unique index for qutoa_definition model

* fix: rubocop errors are fixed

* fix: error message fixed for service_broker model

* fix: service_broker validate_unique reintroduced because, it uses this validation in service_broker_registraion service to refraing http call invalid brokers

* fix: service_broker validate_unique reintroduced because, it uses this validation in service_key_manager to refraing http call in service_key_create

* fix: service_broker validation_unique is removed

* fix: typos are fixed

* fix: concurrent context tests are removed in unit/actions. Uniqueness tests are reintroduced in unit/models.

* fix: changes reverted because if we remove validate_uniqueness, it fires name_overlap and that leads misleading error

* fix: add comment explaining rescue Sequel::ValidationFailed in service broker registration

The around_save hook on the ServiceBroker model catches unique constraint
violations and adds errors to the model before raising ValidationFailed.
The rescue block returns nil, and callers access errors via the delegated
errors method.

* fix: service_broker validation_unique removel is reverted. Since it is used as guard before calling some http endpoint in check in service_broker_registration. Comments are added

Author: serdarozerr

app/models/runtime/app_model.rb

@@ -84,7 +84,7 @@ def around_save
     rescue Sequel::UniqueConstraintViolation => e
       raise e unless e.message.include?('apps_v3_space_guid_name_index')
 
-      errors.add(%i[space_guid name], :unique)
+      errors.add(%i[space_guid name], Sequel.lit("App with the name '#{name}' already exists."))
       raise validation_failed_error
     rescue Sequel::ForeignKeyConstraintViolation => e
       raise e unless e.message.include?('fk_apps_droplet_guid')
@@ -99,8 +99,6 @@ def validate
       validates_format APP_NAME_REGEX, :name
       validate_environment_variables
       validate_droplet_is_staged
-
-      validates_unique %i[space_guid name], message: Sequel.lit("App with the name '#{name}' already exists.")
     end
 
     def lifecycle_type

app/models/runtime/domain.rb

@@ -97,6 +97,8 @@ def around_save
 
     def validate
       validates_presence :name
+      # Keep validates_unique to check across all Domain subclasses (STI: SharedDomain, PrivateDomain).
+      # Without it, exact name duplicates would be caught by name_overlaps? below with a misleading error message.
       validates_unique :name, dataset: Domain.dataset
 
       validates_format CloudController::DomainDecorator::DOMAIN_REGEX, :name,

app/models/runtime/feature_flag.rb

@@ -43,9 +43,17 @@ class UndefinedFeatureFlagError < StandardError
     export_attributes :name, :enabled, :error_message
     import_attributes :name, :enabled, :error_message
 
+    def around_save
+      yield
+    rescue Sequel::UniqueConstraintViolation => e
+      raise e unless e.message.include?('feature_flags_name_index')
+
+      errors.add(:name, :unique)
+      raise validation_failed_error
+    end
+
     def validate
       validates_presence :name
-      validates_unique :name
       validates_presence :enabled
 
       validates_includes DEFAULT_FLAGS.keys.map(&:to_s), :name

app/models/runtime/helpers/organization_role_mixin.rb

@@ -24,7 +24,6 @@ def around_save
     end
 
     def validate
-      validates_unique %i[organization_id user_id]
       validates_presence :organization_id
       validates_presence :user_id
     end

app/models/runtime/helpers/space_role_mixin.rb

@@ -26,7 +26,6 @@ def around_save
     def validate
       validates_presence :space_id
       validates_presence :user_id
-      validates_unique %i[space_id user_id]
     end
   end
 end

app/models/runtime/isolation_segment_model.rb

@@ -25,14 +25,12 @@ def around_save
     rescue Sequel::UniqueConstraintViolation => e
       raise e unless e.message.include?('isolation_segment_name_unique_constraint')
 
-      errors.add(:name, :unique)
+      errors.add(:name, Sequel.lit('Isolation Segment names are case insensitive and must be unique'))
       raise validation_failed_error
     end
 
     def validate
       validates_format ISOLATION_SEGMENT_MODEL_REGEX, :name, message: Sequel.lit('Isolation Segment names can only contain non-blank unicode characters')
-
-      validates_unique [:name], message: Sequel.lit('Isolation Segment names are case insensitive and must be unique')
     end
 
     def is_shared_segment?

app/models/runtime/organization.rb

@@ -218,7 +218,6 @@ def around_save
 
     def validate
       validates_presence :name
-      validates_unique :name
       validates_format ORG_NAME_REGEX, :name
       validates_includes ORG_STATUS_VALUES, :status, allow_missing: true
 

app/models/runtime/quota_definition.rb

@@ -30,7 +30,6 @@ def around_save
 
     def validate
       validates_presence :name
-      validates_unique :name
       validates_presence :non_basic_services_allowed
       validates_presence :total_services
       validates_presence :total_routes

app/models/runtime/space.rb

@@ -229,7 +229,6 @@ def around_save
     def validate
       validates_presence :name
       validates_presence :organization
-      validates_unique %i[organization_id name]
       validates_format SPACE_NAME_REGEX, :name
 
       errors.add(:space_quota_definition, :invalid_organization) if space_quota_definition && space_quota_definition.organization_id != organization.id

app/models/runtime/space_quota_definition.rb

@@ -41,7 +41,6 @@ def validate
       validates_presence :total_routes
       validates_presence :memory_limit
       validates_presence :organization
-      validates_unique %i[organization_id name]
 
       validates_limit(:memory_limit, memory_limit)
       validates_limit(:instance_memory_limit, instance_memory_limit)