Do not allow leaving __world__ group

src/sidebar/helpers/groups.ts

@@ -18,6 +18,8 @@ function allowLeavingGroups(settings: SidebarSettings): boolean {
   return !!config.allowLeavingGroups;
 }
 
+export const PUBLIC_GROUP_ID = '__world__';
+
 /**
  * Combine groups from multiple api calls together to form a unique list of groups.
  * Add an isMember property to each group indicating whether the logged in user is a member.
@@ -34,7 +36,7 @@ export function combineGroups(
   uri: string | null,
   settings: SidebarSettings,
 ) {
-  const worldGroup = featuredGroups.find(g => g.id === '__world__');
+  const worldGroup = featuredGroups.find(g => g.id === PUBLIC_GROUP_ID);
   if (worldGroup) {
     userGroups.unshift(worldGroup);
   }
@@ -50,7 +52,11 @@ export function combineGroups(
 
   // Set flag indicating whether user can leave group.
   for (const group of groups) {
-    group.canLeave = allowLeavingGroups(settings) && group.isMember;
+    group.canLeave =
+      allowLeavingGroups(settings) &&
+      group.isMember &&
+      // People should not be able to leave the "Public" group.
+      group.id !== PUBLIC_GROUP_ID;
   }
 
   // Add isScopedToUri property indicating whether a group is within scope

src/sidebar/helpers/test/groups-test.js

@@ -97,6 +97,40 @@ describe('sidebar/helpers/groups', () => {
       },
     );
 
+    it('sets `canLeave` to false for the `__world__` group', () => {
+      const userGroups = [
+        { id: '__world__', name: 'Public', type: 'open' },
+        { id: 'groupa', name: 'GroupA', type: 'private' },
+        { id: 'groupc', name: 'GroupC', type: 'open' },
+        { id: 'groupd', name: 'GroupD', type: 'restricted' },
+      ];
+      const groups = combineGroups(userGroups, [], 'https://foo.com/bar');
+
+      const expected = [
+        {
+          id: '__world__',
+          canLeave: false,
+        },
+        {
+          id: 'groupa',
+          canLeave: true,
+        },
+        {
+          id: 'groupc',
+          canLeave: true,
+        },
+        {
+          id: 'groupd',
+          canLeave: true,
+        },
+      ];
+
+      for (const { id, canLeave } of expected) {
+        const group = groups.find(g => g.id === id);
+        assert.strictEqual(group.canLeave, canLeave);
+      }
+    });
+
     it('combines groups from both lists uniquely', () => {
       const userGroups = [
         { id: 'groupa', name: 'GroupA' },

src/sidebar/services/groups.ts

@@ -7,7 +7,7 @@ import type { SidebarSettings } from '../../types/config';
 import type { Service } from '../../types/config';
 import { serviceConfig } from '../config/service-config';
 import { isReply } from '../helpers/annotation-metadata';
-import { combineGroups } from '../helpers/groups';
+import { combineGroups, PUBLIC_GROUP_ID } from '../helpers/groups';
 import type { SidebarStore } from '../store';
 import { awaitStateChange } from '../store/util';
 import { watch } from '../util/watch';
@@ -121,7 +121,7 @@ export class GroupsService {
     // If the main document URL has no groups associated with it, always show
     // the "Public" group.
     const pageHasAssociatedGroups = groups.some(
-      g => g.id !== '__world__' && g.isScopedToUri,
+      g => g.id !== PUBLIC_GROUP_ID && g.isScopedToUri,
     );
     if (!pageHasAssociatedGroups) {
       return groups;
@@ -130,14 +130,14 @@ export class GroupsService {
     // If directLinkedGroup or directLinkedAnnotationGroupId is the "Public" group,
     // always return groups.
     if (
-      directLinkedGroupId === '__world__' ||
-      directLinkedAnnotationGroupId === '__world__'
+      directLinkedGroupId === PUBLIC_GROUP_ID ||
+      directLinkedAnnotationGroupId === PUBLIC_GROUP_ID
     ) {
       return groups;
     }
 
     // Return non-world groups.
-    return groups.filter(g => g.id !== '__world__');
+    return groups.filter(g => g.id !== PUBLIC_GROUP_ID);
   }
 
   /**