[59539] Only set lag for the closest relation in the migration

app/workers/work_packages/automatic_mode/migrate_values_job.rb

@@ -103,6 +103,7 @@ def set_lags_for_follows_relations
 
     # Here is the algorithm:
     # - Take all follows relations with dates
+    # - Filter to keep only the closest relation for a same successor
     # - Generate a series of dates between the min date and the max date and
     #   filter for working days
     # - Use both information to count the number of working days between
@@ -111,6 +112,7 @@ def set_lags_for_follows_relations
       WITH follows_relations_with_dates AS (
         SELECT
           relations.id as id,
+          relations.from_id as succ_id,
           COALESCE(wp_pred.due_date, wp_pred.start_date) as pred_date,
           COALESCE(wp_succ.start_date, wp_succ.due_date) as succ_date
         FROM relations
@@ -120,6 +122,14 @@ def set_lags_for_follows_relations
           AND COALESCE(wp_pred.due_date, wp_pred.start_date) IS NOT NULL
           AND COALESCE(wp_succ.start_date, wp_succ.due_date) IS NOT NULL
       ),
+      closest_follows_relations_with_dates AS (
+        SELECT DISTINCT ON (succ_id)
+          id,
+          pred_date,
+          succ_date
+        FROM follows_relations_with_dates
+        ORDER BY succ_id, pred_date DESC
+      ),
       working_dates AS (
         SELECT date::date
         FROM generate_series(
@@ -137,8 +147,8 @@ def set_lags_for_follows_relations
         WHERE date > pred_date
           AND date < succ_date
       )
-      FROM follows_relations_with_dates
-      WHERE relations.id = follows_relations_with_dates.id
+      FROM closest_follows_relations_with_dates
+      WHERE relations.id = closest_follows_relations_with_dates.id
     SQL
   end
 

spec/migrations/update_scheduling_mode_and_lags_spec.rb

@@ -222,4 +222,21 @@
       expect(relations.map(&:lag)).to eq([0, 0, 2])
     end
   end
+
+  context "for a work package following multiple work packages" do
+    shared_let_work_packages(<<~TABLE)
+      subject       | MTWTFSS | properties
+      predecessor 1 | XX      |
+      predecessor 2 |  XX     |
+      predecessor 3 | X       |
+      follower      |      XX | follows predecessor 1, follows predecessor 2, follows predecessor 3
+    TABLE
+
+    it "sets a lag only to the closest relation" do
+      run_migration
+
+      relations = _table.relations.map(&:reload)
+      expect(relations.map(&:lag)).to eq([0, 2, 0])
+    end
+  end
 end