feat: validate entity and event aggregate_id value and type (#80)

#### Why <!-- A short description of why this change is required -->

Eventsimple requires both event and entity to specify entity column used
as `aggregate_id` in the event. This provides flexibility to use
different attribute than primary key to connect event to the entity
class.

It's possible to accidentally set different value for this attribute.
This does not break Eventsimple behaviour, but it introduces
unpredictable behaviour when reading event history.

It's also possible to accidentally set different type on
`event.aggregate_id` column that does not support entity aggregate value
type. This breaks Eventsimple behaviour as events cannot be inserted
into database.

#### What changed <!-- Summary of changes when modifying hundreds of
lines -->

We added validation that `aggregate_id` argument value and column type
matches between event and entity.

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#### Next steps [ If your PR is part of a few or a WIP, give context to
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CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## 1.5.5 - 2024-12-23
+### Changed
+- Validate value and type of `aggregate_id` between Event and Entity
+
 ## 1.5.4 - 2024-12-05
 ### Changed
 - Rails 8.0 is supported

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    eventsimple (1.5.4)
+    eventsimple (1.5.5)
       concurrent-ruby (>= 1.2.3)
       dry-struct (~> 1.6)
       dry-types (~> 1.7)
@@ -185,7 +185,7 @@ GEM
     mini_mime (1.1.5)
     minitest (5.25.4)
     nenv (0.3.0)
-    net-imap (0.5.1)
+    net-imap (0.5.4)
       date
       net-protocol
     net-pop (0.1.2)
@@ -336,7 +336,7 @@ GEM
       rubocop-rails (~> 2.26.0)
     stringio (3.1.2)
     thor (1.3.2)
-    timeout (0.4.2)
+    timeout (0.4.3)
     treetop (1.6.12)
       polyglot (~> 0.3)
     tzinfo (2.0.6)

lib/eventsimple/entity.rb

@@ -3,6 +3,18 @@ module Entity
     DEFAULT_IGNORE_PROPS = %w[id lock_version].freeze
 
     def event_driven_by(event_klass, aggregate_id:, filter_attributes: [])
+      if defined?(event_klass._aggregate_id)
+        raise ArgumentError, "aggregate_id mismatch event:#{event_klass._aggregate_id} entity:#{aggregate_id}" if aggregate_id != event_klass._aggregate_id
+
+        begin
+          aggregate_column_type_in_event = event_klass.column_for_attribute(:aggregate_id).type
+          aggregate_column_type_in_entity = column_for_attribute(aggregate_id).type
+
+          raise ArgumentError, "column type mismatch - event:#{aggregate_column_type_in_event} entity:#{aggregate_column_type_in_entity}" if aggregate_column_type_in_event != aggregate_column_type_in_entity
+        rescue ActiveRecord::NoDatabaseError
+        end
+      end
+
       has_many :events, class_name: event_klass.name.to_s,
         foreign_key: :aggregate_id,
         primary_key: aggregate_id,
@@ -18,6 +30,9 @@ def event_driven_by(event_klass, aggregate_id:, filter_attributes: [])
       class_attribute :_filter_attributes
       self._filter_attributes = [aggregate_id] | Array.wrap(filter_attributes)
 
+      class_attribute :_aggregate_id
+      self._aggregate_id = aggregate_id
+
       # disable automatic timestamp updates
       self.record_timestamps = false
 

lib/eventsimple/event.rb

@@ -5,6 +5,18 @@ module Event
 
     # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
     def drives_events_for(aggregate_klass, aggregate_id:, events_namespace: nil)
+      if defined?(aggregate_klass._aggregate_id)
+        raise ArgumentError, "aggregate_id mismatch event:#{aggregate_id} entity:#{aggregate_klass._aggregate_id}" if aggregate_id != aggregate_klass._aggregate_id
+
+        begin
+          aggregate_column_type_in_event = aggregate_klass.column_for_attribute(aggregate_klass._aggregate_id).type unless aggregate_klass.attribute_names.blank?
+          aggregate_column_type_in_entity = column_for_attribute(:aggregate_id).type unless aggregate_klass.attribute_names.blank?
+
+          raise ArgumentError, "column type mismatch - event:#{aggregate_column_type_in_event} entity:#{aggregate_column_type_in_entity}" if aggregate_column_type_in_event != aggregate_column_type_in_entity
+        rescue ActiveRecord::NoDatabaseError
+        end
+      end
+
       class_attribute :_events_namespace
       self._events_namespace = events_namespace
 

lib/eventsimple/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Eventsimple
-  VERSION = '1.5.4'
+  VERSION = '1.5.5'
 end

spec/lib/eventsimple/entity_spec.rb

@@ -12,6 +12,45 @@ module Eventsimple
       )
     end
 
+    describe '.event_driven_by' do
+      context 'when aggregate_id value mismatch between entity and event' do
+        let(:user_class) do
+          Class.new(ApplicationRecord) do
+            extend Eventsimple::Entity
+
+            event_driven_by UserEvent, aggregate_id: :id
+          end
+        end
+
+        it 'raises argument error' do
+          expect { user_class }.to(raise_error(ArgumentError, 'aggregate_id mismatch event:canonical_id entity:id'))
+        end
+      end
+
+      context 'when aggregate_id column type mismatch between entity and event' do
+        let(:user_class) do
+          Class.new(ApplicationRecord) do
+            def self.name
+              'User'
+            end
+
+            def self.column_for_attribute(column_name)
+              return Struct.new(:type).new(:int) if column_name == :canonical_id
+              super
+            end
+
+            extend Eventsimple::Entity
+
+            event_driven_by UserEvent, aggregate_id: :canonical_id
+          end
+        end
+
+        it 'raises argument error' do
+          expect { user_class }.to(raise_error(ArgumentError, 'column type mismatch - event:string entity:int'))
+        end
+      end
+    end
+
     describe '#projection_matches_events?' do
       it 'returns false if the entity no longer matches state from events' do
         expect(user.projection_matches_events?).to be true

spec/lib/eventsimple/event_spec.rb

@@ -62,4 +62,43 @@ def self.uses_transaction?(_method) = true
       end
     end
   end
+
+  describe '.event_driven_by' do
+    context 'when aggregate_id mismatch between entity and event' do
+      let(:event_class) do
+        Class.new(ApplicationRecord) do
+          extend Eventsimple::Event
+
+          drives_events_for User, aggregate_id: :id, events_namespace: 'UserComponent::Events'
+        end
+      end
+
+      it 'raises argument error' do
+        expect { event_class }.to(raise_error(ArgumentError, 'aggregate_id mismatch event:id entity:canonical_id'))
+      end
+    end
+
+    context 'when aggregate_id column type mismatch between entity and event' do
+      let(:event_class) do
+        Class.new(ApplicationRecord) do
+          def self.name
+            'UserEvent'
+          end
+
+          def self.column_for_attribute(column_name)
+            return Struct.new(:type).new(:int) if column_name == :aggregate_id
+            super
+          end
+
+          extend Eventsimple::Event
+
+          drives_events_for User, aggregate_id: :canonical_id, events_namespace: 'UserComponent::Events'
+        end
+      end
+
+      it 'raises argument error' do
+        expect { event_class }.to(raise_error(ArgumentError, 'column type mismatch - event:string entity:int'))
+      end
+    end
+  end
 end