Merge branch '698-leave-edition-as-a-teacher' into 'development'

Resolve "Leave edition as a teacher"

Closes #698

See merge request !772

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 - Feedbacks are now soft deleted correctly. [@hpage](https://gitlab.ewi.tudelft.nl/hpage)
+- Teachers that are the only teacher for an edition now can't leave the edition. [@aturgut](https://gitlab.ewi.tudelft.nl/aturgut)
 
 ## [2.3.1]
 

src/main/java/nl/tudelft/queue/service/PermissionService.java

@@ -101,6 +101,9 @@ public class PermissionService {
 	@Lazy
 	private RequestService rs;
 
+	@Autowired
+	private RoleDTOService rds;
+
 	/**
 	 * Gets the Person associated to the currently authenticated entity and passes it to the given callback.
 	 * If no API Key with user could be found, this function just outputs {@code false}.
@@ -451,10 +454,15 @@ public class PermissionService {
 	 * @return           Whether the authenticated user can remove themselves from an edition. A user may not
 	 *                   leave the course they are in if their role in the course is already linked to a
 	 *                   student group, as this means they might have requests, submissions, or even grades in
-	 *                   the course that cannot be disassociated with the user.
+	 *                   the course that cannot be disassociated with the user. A user that is the only
+	 *                   teacher of the edition can't leave the edition.
 	 */
 	public boolean canLeaveEdition(Long editionId) {
-		return withRole(editionId, (person, role) -> STAFF_ROLES.contains(role) ||
+		return withRole(editionId, (person, role) -> (STAFF_ROLES.contains(role) &&
+				withEdition(editionId, edition -> {
+					return !rds.isTheOnlyTeacherInEdition(person.getId(), edition);
+				}))
+				||
 				(role == STUDENT && withEdition(editionId, edition -> {
 					var groups = sgCache.getByPerson(person.getId());
 					var modules = edition.getModules().stream()
@@ -566,11 +574,6 @@ public class PermissionService {
 	 * @param  editionId The id of an edition
 	 * @return           Whether the authenticated user can manage the questions of an edition
 	 */
-	/**
-	 * @param  editionId The id of the edition the user wants to manage.
-	 * @return           Whether the authenticated user can change some values within the settings of the
-	 *                   edition.
-	 */
 	public boolean canManageQuestions(Long editionId) {
 		return isAdmin() || withRole(editionId, (person, role) -> TEACHER == role || HEAD_TA == role);
 	}