Подготовить безопасный production rollout

backend/src/main/resources/db/migration/V1__init.sql

@@ -731,12 +731,31 @@ CREATE TABLE IF NOT EXISTS academic_calendar_days (
 CREATE INDEX IF NOT EXISTS idx_calendar_days_lookup
     ON academic_calendar_days(calendar_id, course_number, date);
 
+CREATE OR REPLACE FUNCTION calculate_academic_calendar_week_number(
+    academic_year_start DATE,
+    calendar_date DATE
+)
+RETURNS INTEGER
+LANGUAGE SQL
+IMMUTABLE
+STRICT
+AS $$
+    SELECT (
+        (
+            calendar_date
+            - academic_year_start
+            + EXTRACT(ISODOW FROM academic_year_start)::INTEGER
+            - 1
+        ) / 7
+    ) + 1
+$$;
+
 INSERT INTO academic_calendar_days (calendar_id, course_number, date, week_number, day_of_week, activity_type_id)
 SELECT
     calendar.id,
     course.course_number,
     days.date::DATE,
-    ((days.date::DATE - ay.start_date) / 7) + 1,
+    calculate_academic_calendar_week_number(ay.start_date, days.date::DATE),
     EXTRACT(ISODOW FROM days.date::DATE)::INT,
     activity.id
 FROM academic_calendars calendar
@@ -1262,6 +1281,8 @@ COMMENT ON COLUMN academic_calendar_days.date IS 'Дата';
 COMMENT ON COLUMN academic_calendar_days.week_number IS 'Номер недели в учебном году';
 COMMENT ON COLUMN academic_calendar_days.day_of_week IS 'День недели ISO';
 COMMENT ON COLUMN academic_calendar_days.activity_type_id IS 'ID кода активности';
+COMMENT ON FUNCTION calculate_academic_calendar_week_number(DATE, DATE)
+    IS 'Номер недели календарного учебного графика по периодам понедельник–воскресенье';
 
 COMMENT ON COLUMN academic_calendar_subjects.calendar_id IS 'ID календарного учебного графика';
 COMMENT ON COLUMN academic_calendar_subjects.semester_number IS 'Номер учебного семестра внутри графика: 1, 2, 3 ...';

backend/src/main/resources/db/migration/V2__align_academic_calendar_weeks_to_monday.sql

@@ -1,23 +0,0 @@
--- Недели календарного учебного графика выровнены по ISO-неделе:
--- понедельник — первый день, воскресенье — последний.
-UPDATE academic_calendar_days AS calendar_day
-SET week_number = (
-    (
-        calendar_day.date
-        - academic_year.start_date
-        + EXTRACT(ISODOW FROM academic_year.start_date)::INTEGER
-        - 1
-    ) / 7
-) + 1
-FROM academic_calendars AS calendar
-JOIN academic_years AS academic_year
-    ON academic_year.id = calendar.academic_year_id
-WHERE calendar_day.calendar_id = calendar.id
-  AND calendar_day.week_number IS DISTINCT FROM (
-      (
-          calendar_day.date
-          - academic_year.start_date
-          + EXTRACT(ISODOW FROM academic_year.start_date)::INTEGER
-          - 1
-      ) / 7
-  ) + 1;