Context merge for experiment conversions

Add context to record_experiment_conversion_event similar to
record_experiment_user

app/models/experiment.rb

@@ -14,22 +14,30 @@ class Experiment < ApplicationRecord
     find_or_create_by!(name: name).record_group_and_variant!(group, variant)
   end
 
-  def self.record_conversion_event(name, user)
-    find_or_create_by!(name: name).record_conversion_event_for_user(user)
+  def self.record_conversion_event(name, user, context = {})
+    find_or_create_by!(name: name).record_conversion_event_for_user(user, context)
   end
 
   # Create or update the recorded experiment_user row for the user in this experiment.
   def record_user_and_group(user, group_type, context = {})
     experiment_user = experiment_users.find_or_initialize_by(user: user)
-    merged_context = experiment_user.context.deep_merge(context.deep_stringify_keys)
-    experiment_user.update!(group_type: group_type, context: merged_context)
+    experiment_user.update!(group_type: group_type, context: merged_context(experiment_user, context))
   end
 
-  def record_conversion_event_for_user(user)
-    experiment_users.find_by(user: user, converted_at: nil)&.touch(:converted_at)
+  def record_conversion_event_for_user(user, context = {})
+    experiment_user = experiment_users.find_by(user: user)
+    return unless experiment_user
+
+    experiment_user.update!(converted_at: Time.current, context: merged_context(experiment_user, context))
   end
 
   def record_group_and_variant!(group, variant)
     experiment_subjects.find_or_initialize_by(group: group).update!(variant: variant)
   end
+
+  private
+
+  def merged_context(experiment_user, new_context)
+    experiment_user.context.deep_merge(new_context.deep_stringify_keys)
+  end
 end

lib/gitlab/experimentation/controller_concern.rb

@@ -72,12 +72,12 @@ module Gitlab
         ::Experiment.add_user(experiment_key, tracking_group(experiment_key, nil, subject: subject), current_user, context)
       end
 
-      def record_experiment_conversion_event(experiment_key)
+      def record_experiment_conversion_event(experiment_key, context = {})
         return if dnt_enabled?
         return unless current_user
         return unless Experimentation.active?(experiment_key)
 
-        ::Experiment.record_conversion_event(experiment_key, current_user)
+        ::Experiment.record_conversion_event(experiment_key, current_user, context)
       end
 
       def experiment_tracking_category_and_group(experiment_key, subject: nil)

spec/lib/gitlab/experimentation/controller_concern_spec.rb

@@ -534,7 +534,7 @@ RSpec.describe Gitlab::Experimentation::ControllerConcern, type: :controller do
     end
 
     it 'records the conversion event for the experiment & user' do
-      expect(::Experiment).to receive(:record_conversion_event).with(:test_experiment, user)
+      expect(::Experiment).to receive(:record_conversion_event).with(:test_experiment, user, {})
       record_conversion_event
     end
 

spec/models/experiment_spec.rb

@@ -98,10 +98,11 @@ RSpec.describe Experiment do
 
   describe '.record_conversion_event' do
     let_it_be(:user) { build(:user) }
+    let_it_be(:context) { { a: 42 } }
 
     let(:experiment_key) { :test_experiment }
 
-    subject(:record_conversion_event) { described_class.record_conversion_event(experiment_key, user) }
+    subject(:record_conversion_event) { described_class.record_conversion_event(experiment_key, user, context) }
 
     context 'when no matching experiment exists' do
       it 'creates the experiment and uses it' do
@@ -127,22 +128,79 @@ RSpec.describe Experiment do
 
       it 'sends record_conversion_event_for_user to the experiment instance' do
         expect_next_found_instance_of(described_class) do |experiment|
-          expect(experiment).to receive(:record_conversion_event_for_user).with(user)
+          expect(experiment).to receive(:record_conversion_event_for_user).with(user, context)
         end
         record_conversion_event
       end
     end
   end
 
+  shared_examples 'experiment user with context' do
+    let_it_be(:context) { { a: 42, 'b' => 34, 'c': { c1: 100, c2: 'c2', e: :e }, d: [1, 3] } }
+    let_it_be(:initial_expected_context) { { 'a' => 42, 'b' => 34, 'c' => { 'c1' => 100, 'c2' => 'c2', 'e' => 'e' }, 'd' => [1, 3] } }
+
+    before do
+      subject
+      experiment.record_user_and_group(user, :experimental, {})
+    end
+
+    it 'has an initial context with stringified keys' do
+      expect(ExperimentUser.last.context).to eq(initial_expected_context)
+    end
+
+    context 'when updated' do
+      before do
+        subject
+        experiment.record_user_and_group(user, :experimental, new_context)
+      end
+
+      context 'with an empty context' do
+        let_it_be(:new_context) { {} }
+
+        it 'keeps the initial context' do
+          expect(ExperimentUser.last.context).to eq(initial_expected_context)
+        end
+      end
+
+      context 'with string keys' do
+        let_it_be(:new_context) { { f: :some_symbol } }
+
+        it 'adds new symbols stringified' do
+          expected_context = initial_expected_context.merge('f' => 'some_symbol')
+          expect(ExperimentUser.last.context).to eq(expected_context)
+        end
+      end
+
+      context 'with atomic values or array values' do
+        let_it_be(:new_context) { { b: 97, d: [99] } }
+
+        it 'overrides the values' do
+          expected_context = { 'a' => 42, 'b' => 97, 'c' => { 'c1' => 100, 'c2' => 'c2', 'e' => 'e' }, 'd' => [99] }
+          expect(ExperimentUser.last.context).to eq(expected_context)
+        end
+      end
+
+      context 'with nested hashes' do
+        let_it_be(:new_context) { { c: { g: 107 } } }
+
+        it 'inserts nested additional values in the same keys' do
+          expected_context = initial_expected_context.deep_merge('c' => { 'g' => 107 })
+          expect(ExperimentUser.last.context).to eq(expected_context)
+        end
+      end
+    end
+  end
+
   describe '#record_conversion_event_for_user' do
     let_it_be(:user) { create(:user) }
     let_it_be(:experiment) { create(:experiment) }
+    let_it_be(:context) { { a: 42 } }
 
-    subject(:record_conversion_event_for_user) { experiment.record_conversion_event_for_user(user) }
+    subject { experiment.record_conversion_event_for_user(user, context) }
 
     context 'when no existing experiment_user record exists for the given user' do
       it 'does not update or create an experiment_user record' do
-        expect { record_conversion_event_for_user }.not_to change { ExperimentUser.all.to_a }
+        expect { subject }.not_to change { ExperimentUser.all.to_a }
       end
     end
 
@@ -151,7 +209,13 @@ RSpec.describe Experiment do
         let!(:experiment_user) { create(:experiment_user, experiment: experiment, user: user, converted_at: 2.days.ago) }
 
         it 'does not update the converted_at value' do
-          expect { record_conversion_event_for_user }.not_to change { experiment_user.converted_at }
+          expect { subject }.not_to change { experiment_user.converted_at }
+        end
+
+        it_behaves_like 'experiment user with context' do
+          before do
+            experiment.record_user_and_group(user, :experimental, context)
+          end
         end
       end
 
@@ -159,7 +223,13 @@ RSpec.describe Experiment do
         let(:experiment_user) { create(:experiment_user, experiment: experiment, user: user) }
 
         it 'updates the converted_at value' do
-          expect { record_conversion_event_for_user }.to change { experiment_user.reload.converted_at }
+          expect { subject }.to change { experiment_user.reload.converted_at }
+        end
+
+        it_behaves_like 'experiment user with context' do
+          before do
+            experiment.record_user_and_group(user, :experimental, context)
+          end
         end
       end
     end
@@ -196,24 +266,25 @@ RSpec.describe Experiment do
   describe '#record_user_and_group' do
     let_it_be(:experiment) { create(:experiment) }
     let_it_be(:user) { create(:user) }
+    let_it_be(:group) { :control }
+    let_it_be(:context) { { a: 42 } }
 
-    let(:group) { :control }
-    let(:context) { { a: 42 } }
-
-    subject(:record_user_and_group) { experiment.record_user_and_group(user, group, context) }
+    subject { experiment.record_user_and_group(user, group, context) }
 
     context 'when an experiment_user does not yet exist for the given user' do
       it 'creates a new experiment_user record' do
-        expect { record_user_and_group }.to change(ExperimentUser, :count).by(1)
+        expect { subject }.to change(ExperimentUser, :count).by(1)
       end
 
       it 'assigns the correct group_type to the experiment_user' do
-        record_user_and_group
+        subject
+
         expect(ExperimentUser.last.group_type).to eq('control')
       end
 
       it 'adds the correct context to the experiment_user' do
-        record_user_and_group
+        subject
+
         expect(ExperimentUser.last.context).to eq({ 'a' => 42 })
       end
     end
@@ -225,72 +296,18 @@ RSpec.describe Experiment do
       end
 
       it 'does not create a new experiment_user record' do
-        expect { record_user_and_group }.not_to change(ExperimentUser, :count)
+        expect { subject }.not_to change(ExperimentUser, :count)
       end
 
       context 'but the group_type and context has changed' do
         let(:group) { :experimental }
 
         it 'updates the existing experiment_user record with group_type' do
-          expect { record_user_and_group }.to change { ExperimentUser.last.group_type }
+          expect { subject }.to change { ExperimentUser.last.group_type }
         end
       end
-    end
-
-    context 'when a context already exists' do
-      let_it_be(:context) { { a: 42, 'b' => 34, 'c': { c1: 100, c2: 'c2', e: :e }, d: [1, 3] } }
-      let_it_be(:initial_expected_context) { { 'a' => 42, 'b' => 34, 'c' => { 'c1' => 100, 'c2' => 'c2', 'e' => 'e' }, 'd' => [1, 3] } }
-
-      before do
-        record_user_and_group
-        experiment.record_user_and_group(user, :control, {})
-      end
-
-      it 'has an initial context with stringified keys' do
-        expect(ExperimentUser.last.context).to eq(initial_expected_context)
-      end
-
-      context 'when updated' do
-        before do
-          record_user_and_group
-          experiment.record_user_and_group(user, :control, new_context)
-        end
-
-        context 'with an empty context' do
-          let_it_be(:new_context) { {} }
 
-          it 'keeps the initial context' do
-            expect(ExperimentUser.last.context).to eq(initial_expected_context)
-          end
-        end
-
-        context 'with string keys' do
-          let_it_be(:new_context) { { f: :some_symbol } }
-
-          it 'adds new symbols stringified' do
-            expected_context = initial_expected_context.merge('f' => 'some_symbol')
-            expect(ExperimentUser.last.context).to eq(expected_context)
-          end
-        end
-
-        context 'with atomic values or array values' do
-          let_it_be(:new_context) { { b: 97, d: [99] } }
-
-          it 'overrides the values' do
-            expected_context = { 'a' => 42, 'b' => 97, 'c' => { 'c1' => 100, 'c2' => 'c2', 'e' => 'e' }, 'd' => [99] }
-            expect(ExperimentUser.last.context).to eq(expected_context)
-          end
-        end
-
-        context 'with nested hashes' do
-          let_it_be(:new_context) { { c: { g: 107 } } }
-
-          it 'inserts nested additional values in the same keys' do
-            expected_context = initial_expected_context.deep_merge('c' => { 'g' => 107 })
-            expect(ExperimentUser.last.context).to eq(expected_context)
-          end
-        end
-      end
+      it_behaves_like 'experiment user with context'
     end
   end
 end