Tweak cycle analytics query to match the current requirements.

- The `review` phase ends when a MR is merged, not "merged OR closed".
- The `code` phase starts when a MR is first mentioned in a commit, and
  ends when a merge request closing the issue is created.
- The `plan` phase ends when the issue first mentioned in a commit.

---

- Fix the `median` function so it sorts the incoming data points.
- A data point where `end_time` is prior to `start_time` is invalid.

1 files changed, 8 insertions, 0 deletions

diff --git a/app/models/cycle_analytics/queries.rb b/app/models/cycle_analytics/queries.rb
index 1a9a1daa2b0..7816c96a0ed 100644
--- a/app/models/cycle_analytics/queries.rb
+++ b/app/models/cycle_analytics/queries.rb
@@ -26,6 +26,14 @@ class CycleAnalytics
         end
       end
 
+      def issue_first_mentioned_in_commit_at
+        lambda do |data_point|
+          issue = data_point[:issue]
+          commits_mentioning_issue = issue.notes.system.map { |note| note.all_references.commits }.flatten
+          commits_mentioning_issue.map(&:committed_date).min if commits_mentioning_issue.present?
+        end
+      end
+
       def merge_request_first_closed_at
         lambda do |data_point|
           merge_request = data_point[:merge_request]