fix: handle exception getting cert statuses (#31490)

If a user has a certificate in a deleted course, an issue with how the
course is loaded from the cache can cause an exception that breaks our
code. This adds a wrapper to fail gracefully and log the exception for
future tracking / investigation.

lms/djangoapps/learner_home/test_views.py

@@ -649,6 +649,42 @@ class TestDashboardView(BaseTestDashboardView):
             },
         )
 
+    @patch.dict(settings.FEATURES, ENTERPRISE_ENABLED=False)
+    @patch("lms.djangoapps.learner_home.views.cert_info")
+    def test_get_cert_statuses_exception(self, mock_get_cert_info):
+        """Test that cert information gets loaded correctly"""
+
+        # Given I am logged in
+        self.log_in()
+
+        # (and we have tons of mocks to avoid integration tests)
+        mock_enrollment = create_test_enrollment(
+            self.user, course_mode=CourseMode.VERIFIED
+        )
+
+        # but have an issue with a particular certificate
+        mock_get_cert_info.side_effect = Exception("test exception")
+
+        # When I request the dashboard
+        response = self.client.get(self.view_url)
+
+        # Then I get the expected success response
+        assert response.status_code == 200
+        response_data = json.loads(response.content)
+
+        empty_cert_data = {
+            "availableDate": None,
+            "isRestricted": False,
+            "isEarned": False,
+            "isDownloadable": False,
+            "certPreviewUrl": None,
+        }
+
+        # with empty cert data instead of a break
+        self.assertDictEqual(
+            response_data["courses"][0]["certificate"], empty_cert_data
+        )
+
     @patch.dict(settings.FEATURES, ENTERPRISE_ENABLED=False)
     @patch("openedx.core.djangoapps.programs.utils.get_programs")
     def test_get_for_one_of_course_programs(self, mock_get_programs):

lms/djangoapps/learner_home/views.py

@@ -238,10 +238,24 @@ def get_ecommerce_payment_page(user):
 @function_trace("get_cert_statuses")
 def get_cert_statuses(user, course_enrollments):
     """Get cert status by course for user enrollments"""
-    return {
-        enrollment.course_id: cert_info(user, enrollment)
-        for enrollment in course_enrollments
-    }
+
+    cert_statuses = {}
+
+    for enrollment in course_enrollments:
+        # APER-2171 - trying to get a cert for a deleted course can throw an exception
+        # Wrap in exception handling to avoid this issue.
+        try:
+            certificate_for_course = cert_info(user, enrollment)
+
+            if certificate_for_course:
+                cert_statuses[enrollment.course_id] = certificate_for_course
+
+        except Exception as ex:  # pylint: disable=broad-except
+            logger.exception(
+                f"Error getting certificate status for (user, course) ({user}, {enrollment.course_id}): {ex}"
+            )
+
+    return cert_statuses
 
 
 @function_trace("get_org_block_and_allow_lists")