fix run matching (#3365)

Author: gumaerc

frontends/main/src/app-pages/DashboardPage/CoursewareDisplay/model/dashboardViewModel.test.ts

@@ -72,6 +72,35 @@ describe("dashboardViewModel", () => {
         pickDisplayedEnrollmentForLegacyDashboard(course, [lower, higher]),
       ).toEqual(higher)
     })
+
+    test("keeps an older enrolled run when the course payload only lists the newer run", () => {
+      const olderRun = factories.courses.courseRun({
+        id: 101,
+        title: "Older run",
+      })
+      const newerRun = factories.courses.courseRun({
+        id: 202,
+        title: "Newer run",
+      })
+      const course = factories.courses.course({
+        id: 77,
+        courseruns: [newerRun],
+        next_run_id: newerRun.id,
+      })
+      const olderEnrollment = factories.enrollment.courseEnrollment({
+        run: {
+          id: olderRun.id,
+          title: olderRun.title,
+          course: { id: course.id, title: course.title },
+        },
+        certificate: null,
+        grades: [],
+      })
+
+      expect(
+        pickDisplayedEnrollmentForLegacyDashboard(course, [olderEnrollment]),
+      ).toEqual(olderEnrollment)
+    })
   })
 
   describe("groupCourseRunEnrollmentsByCourseId", () => {

frontends/main/src/app-pages/DashboardPage/CoursewareDisplay/model/dashboardViewModel.ts

@@ -77,6 +77,17 @@ const getMaxEnrollmentGrade = (enrollment: CourseRunEnrollmentV3): number => {
   return Math.max(0, ...enrollment.grades.map((grade) => grade.grade ?? 0))
 }
 
+const enrollmentBelongsToCourse = (
+  course: CourseWithCourseRunsSerializerV2,
+  enrollment: CourseRunEnrollmentV3,
+): boolean => {
+  if (enrollment.run.course?.id === course.id) {
+    return true
+  }
+
+  return course.courseruns.some((run) => run.id === enrollment.run.id)
+}
+
 /**
  * Legacy display policy used by dashboard cards.
  *
@@ -90,7 +101,7 @@ const pickDisplayedEnrollmentForLegacyDashboard = (
   enrollments: CourseRunEnrollmentV3[],
 ): CourseRunEnrollmentV3 | null => {
   const courseEnrollments = enrollments.filter((enrollment) =>
-    course.courseruns.some((run) => run.id === enrollment.run.id),
+    enrollmentBelongsToCourse(course, enrollment),
   )
   if (courseEnrollments.length === 0) {
     return null