fix: unenrolled default intentions not realizable

The default enrollment ``learner_status`` view now considers intended courses from which the requested user has unenrolled as no-longer realizable.
ENT-9839

CHANGELOG.rst

@@ -17,6 +17,11 @@ Unreleased
 ----------
 * nothing unreleased
 
+[5.4.1]
+--------
+* fix: The default enrollment ``learner_status`` view now considers intended courses
+  from which the requested user has unenrolled as no-longer realizable.
+
 [5.4.0]
 --------
 * chore: Update python requirements.

enterprise/__init__.py

@@ -2,4 +2,4 @@
 Your project description goes here.
 """
 
-__version__ = "5.4.0"
+__version__ = "5.4.1"

enterprise/api/v1/views/default_enterprise_enrollments.py

@@ -211,6 +211,17 @@ def _partition_default_enrollment_intentions_by_enrollment_status(
                 already_enrolled.append((intention, non_audit_enrollment))
                 continue
 
+            if non_audit_enrollment and non_audit_enrollment.unenrolled:
+                # Learner has un-enrolled in non-audit mode for this course run,
+                # so don't consider this as an enrollable intention.
+                # Note that that we don't consider the case of an unenrolled *audit* enrollment,
+                # because default enrollments should be "exactly once" per (user, enterprise), if possible.
+                # If only an (unenrolled) audit enrollment exists, it means the user likely
+                # never had a default intention realized for them in the given course,
+                # so we'd still like to consider it as enrollable.
+                needs_enrollment_not_enrollable.append((intention, non_audit_enrollment))
+                continue
+
             if not intention.is_course_run_enrollable:
                 # Course run is not enrollable
                 needs_enrollment_not_enrollable.append((intention, audit_enrollment))