Track usage pings when MR gets locked/unlocked

We need to track how many users locks/unlocks a merge request.

To get that, whenever the `discussion_locked` gets toggled for a
merge request, we track the following events:

- i_code_review_user_mr_discussion_locked
- i_code_review_user_mr_discussion_unlocked

app/services/merge_requests/update_service.rb

@@ -47,6 +47,7 @@ module MergeRequests
       handle_draft_status_change(merge_request, changed_fields)
 
       track_title_and_desc_edits(changed_fields)
+      track_discussion_lock_toggle(merge_request, changed_fields)
 
       notify_if_labels_added(merge_request, old_labels)
       notify_if_mentions_added(merge_request, old_mentioned_users)
@@ -95,6 +96,16 @@ module MergeRequests
       end
     end
 
+    def track_discussion_lock_toggle(merge_request, changed_fields)
+      return unless changed_fields.include?('discussion_locked')
+
+      if merge_request.discussion_locked
+        merge_request_activity_counter.track_discussion_locked_action(user: current_user)
+      else
+        merge_request_activity_counter.track_discussion_unlocked_action(user: current_user)
+      end
+    end
+
     def notify_if_labels_added(merge_request, old_labels)
       added_labels = merge_request.labels - old_labels
 

changelogs/unreleased/292824-track-mr-lock-changes.yml

+---
+title: Track usage pings when MR gets locked/unlocked
+merge_request: 55069
+author:
+type: other

config/feature_flags/development/usage_data_i_code_review_user_mr_discussion_locked.yml

+---
+name: usage_data_i_code_review_user_mr_discussion_locked
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/55069
+rollout_issue_url:
+milestone: '13.10'
+type: development
+group: group::code review
+default_enabled: true

config/feature_flags/development/usage_data_i_code_review_user_mr_discussion_unlocked.yml

+---
+name: usage_data_i_code_review_user_mr_discussion_unlocked
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/55069
+rollout_issue_url:
+milestone: '13.10'
+type: development
+group: group::code review
+default_enabled: true

lib/gitlab/usage_data_counters/aggregated_metrics/code_review.yml

@@ -42,7 +42,9 @@
     'i_code_review_user_approval_rule_edited',
     'i_code_review_user_vs_code_api_request',
     'i_code_review_user_toggled_task_item_status',
-    'i_code_review_user_create_mr_from_issue'
+    'i_code_review_user_create_mr_from_issue',
+    'i_code_review_user_mr_discussion_locked',
+    'i_code_review_user_mr_discussion_unlocked'
   ]
 - name: code_review_category_monthly_active_users
   operator: OR
@@ -78,7 +80,9 @@
     'i_code_review_user_approval_rule_deleted',
     'i_code_review_user_approval_rule_edited',
     'i_code_review_user_toggled_task_item_status',
-    'i_code_review_user_create_mr_from_issue'
+    'i_code_review_user_create_mr_from_issue',
+    'i_code_review_user_mr_discussion_locked',
+    'i_code_review_user_mr_discussion_unlocked'
   ]
 - name: code_review_extension_category_monthly_active_users
   operator: OR

lib/gitlab/usage_data_counters/known_events/code_review_events.yml

@@ -164,3 +164,13 @@
   category: code_review
   aggregation: weekly
   feature_flag: usage_data_i_code_review_user_create_mr_from_issue
+- name: i_code_review_user_mr_discussion_locked
+  redis_slot: code_review
+  category: code_review
+  aggregation: weekly
+  feature_flag: usage_data_i_code_review_user_mr_discussion_locked
+- name: i_code_review_user_mr_discussion_unlocked
+  redis_slot: code_review
+  category: code_review
+  aggregation: weekly
+  feature_flag: usage_data_i_code_review_user_mr_discussion_unlocked

lib/gitlab/usage_data_counters/merge_request_activity_unique_counter.rb

@@ -35,6 +35,8 @@ module Gitlab
       MR_EDIT_MR_TITLE_ACTION = 'i_code_review_edit_mr_title'
       MR_EDIT_MR_DESC_ACTION = 'i_code_review_edit_mr_desc'
       MR_CREATE_FROM_ISSUE_ACTION = 'i_code_review_user_create_mr_from_issue'
+      MR_DISCUSSION_LOCKED_ACTION = 'i_code_review_user_mr_discussion_locked'
+      MR_DISCUSSION_UNLOCKED_ACTION = 'i_code_review_user_mr_discussion_unlocked'
 
       class << self
         def track_mr_diffs_action(merge_request:)
@@ -153,6 +155,14 @@ module Gitlab
           track_unique_action_by_user(MR_CREATE_FROM_ISSUE_ACTION, user)
         end
 
+        def track_discussion_locked_action(user:)
+          track_unique_action_by_user(MR_DISCUSSION_LOCKED_ACTION, user)
+        end
+
+        def track_discussion_unlocked_action(user:)
+          track_unique_action_by_user(MR_DISCUSSION_UNLOCKED_ACTION, user)
+        end
+
         private
 
         def track_unique_action_by_merge_request(action, merge_request)

spec/lib/gitlab/usage_data_counters/merge_request_activity_unique_counter_spec.rb

@@ -284,4 +284,20 @@ RSpec.describe Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter, :cl
       let(:action) { described_class::MR_CREATE_FROM_ISSUE_ACTION }
     end
   end
+
+  describe '.track_discussion_locked_action' do
+    subject { described_class.track_discussion_locked_action(user: user) }
+
+    it_behaves_like 'a tracked merge request unique event' do
+      let(:action) { described_class::MR_DISCUSSION_LOCKED_ACTION }
+    end
+  end
+
+  describe '.track_discussion_unlocked_action' do
+    subject { described_class.track_discussion_unlocked_action(user: user) }
+
+    it_behaves_like 'a tracked merge request unique event' do
+      let(:action) { described_class::MR_DISCUSSION_UNLOCKED_ACTION }
+    end
+  end
 end

spec/services/merge_requests/update_service_spec.rb

@@ -117,6 +117,28 @@ RSpec.describe MergeRequests::UpdateService, :mailer do
 
           MergeRequests::UpdateService.new(project, user, opts).execute(draft_merge_request)
         end
+
+        it 'tracks discussion locking' do
+          merge_request.update!(discussion_locked: false)
+
+          expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
+            .to receive(:track_discussion_locked_action).once.with(user: user)
+
+          opts[:discussion_locked] = true
+
+          MergeRequests::UpdateService.new(project, user, opts).execute(merge_request)
+        end
+
+        it 'tracks dicussion unlocking' do
+          merge_request.update!(discussion_locked: true)
+
+          expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
+            .to receive(:track_discussion_unlocked_action).once.with(user: user)
+
+          opts[:discussion_locked] = false
+
+          MergeRequests::UpdateService.new(project, user, opts).execute(merge_request)
+        end
       end
 
       context 'updating milestone' do