Don't pretend we can add/remove users to/from groups when we can't

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/Group/Group.php

@@ -30,6 +30,7 @@
 
 namespace OC\Group;
 
+use OCP\GroupInterface;
 use OCP\IGroup;
 use OCP\IUser;
 use OCP\Group\Backend\ICountDisabledInGroup;
@@ -323,4 +324,30 @@ class Group implements IGroup {
 		}
 		return $users;
 	}
+
+	/**
+	 * @return bool
+	 * @since 14.0.0
+	 */
+	public function canRemoveUser() {
+		foreach ($this->backends as $backend) {
+			if ($backend->implementsActions(GroupInterface::REMOVE_FROM_GOUP)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	/**
+	 * @return bool
+	 * @since 14.0.0
+	 */
+	public function canAddUser() {
+		foreach ($this->backends as $backend) {
+			if ($backend->implementsActions(GroupInterface::ADD_TO_GROUP)) {
+				return true;
+			}
+		}
+		return false;
+	}
 }

lib/private/Group/MetaData.php

@@ -165,7 +165,9 @@ class MetaData {
 				'id' => $group->getGID(),
 				'name' => $group->getDisplayName(),
 				'usercount' => $this->sorting === self::SORT_USERCOUNT ? $group->count($userSearch) : 0,
-				'disabled' => $group->countDisabled()
+				'disabled' => $group->countDisabled(),
+				'canAdd' => $group->canAddUser(),
+				'canRemove' => $group->canRemoveUser(),
 			);
 	}
 

lib/public/IGroup.php

@@ -126,4 +126,16 @@ interface IGroup {
 	 * @since 8.0.0
 	 */
 	public function delete();
+
+	/**
+	 * @return bool
+	 * @since 14.0.0
+	 */
+	public function canRemoveUser();
+
+	/**
+	 * @return bool
+	 * @since 14.0.0
+	 */
+	public function canAddUser();
 }

settings/src/components/userList/userRow.vue

@@ -374,6 +374,9 @@ export default {
 		 * @returns {Promise}
 		 */
 		addUserGroup(group) {
+			if (!group.canAdd) {
+				return false;
+			}
 			this.loading.groups = true;
 			let userid = this.user.id;
 			let gid = group.id;
@@ -388,6 +391,9 @@ export default {
 		 * @returns {Promise}
 		 */
 		removeUserGroup(group) {
+			if (!group.canRemove) {
+				return false;
+			}
 			this.loading.groups = true;
 			let userid = this.user.id;
 			let gid = group.id;