Change Details

This addresses [ENG-9030](https://linear.app/comm/issue/ENG-9030/announcement-roots-restrict-permissions-in-descendant-chats). The `memberUserSurfacedPermissions` calculation currently in the codebase basically controls the default set of user-surfaced permissions granted to a member. The problem is that right now, this default set is different depending on the community root's `ThreadType`. I think the intention of that logic is to restrict permissions in the community root, but user-surfaced permissions are meant to be global for the whole community, so this doesn't make sense. This issue wasn't noticed prior to D13017 because the user-surfaced permissions were only affecting the root. Now that they're affecting the whole community, we need to revisit this logic. This diff introduces a new approach: 1. The code for determining `memberUserSurfacedPermissions` is removed, in favor of assigning the same set of default user-surfaced permissions to all members, regardless of the community root's `ThreadType`. 2. We also remove a similar distinction in `getRolePermissionBlobs` for announcement subchannels, since they can be handled by the same mechanism that we need to replace point 1 above. 3. Both 1 and 2 are replaced with logic in `permissionLookup`, where we subtract a set of permissions for announcement threads where the user doesn't have `VOICED_IN_ANNOUNCEMENT_CHANNELS`. Depends on D13067

This addresses [ENG-9030](https://linear.app/comm/issue/ENG-9030/announcement-roots-restrict-permissions-in-descendant-chats). The `memberUserSurfacedPermissions` calculation currently in the codebase basically controls the default set of user-surfaced permissions granted to a member. The problem is that right now, this default set is different depending on the community root's `ThreadType`. I think the intention of that logic is to restrict permissions in the community root, but user-surfaced permissions are meant to be global for the whole community, so this doesn't make sense. This issue wasn't noticed prior to D13017 because the user-surfaced permissions were only affecting the root. Now that they're affecting the whole community, we need to revisit this logic. This diff introduces a new approach: 1. The code for determining `memberUserSurfacedPermissions` is removed, in favor of assigning the same set of default user-surfaced permissions to all members, regardless of the community root's `ThreadType`. 2. We also remove a similar distinction in `getRolePermissionBlobs` for announcement subchannels, since they can be handled by the same mechanism that we need to replace point 1 above. 3. Both 1 and 2 are replaced with logic in `makePermissionsBlob`, where we subtract a set of permissions for announcement threads where the user doesn't have `VOICED_IN_ANNOUNCEMENT_CHANNELS`. Depends on D13067

This addresses [ENG-9030](https://linear.app/comm/issue/ENG-9030/announcement-roots-restrict-permissions-in-descendant-chats). The `memberUserSurfacedPermissions` calculation currently in the codebase basically controls the default set of user-surfaced permissions granted to a member. The problem is that right now, this default set is different depending on the community root's `ThreadType`. I think the intention of that logic is to restrict permissions in the community root, but user-surfaced permissions are meant to be global for the whole community, so this doesn't make sense. This issue wasn't noticed prior to D13017 because the user-surfaced permissions were only affecting the root. Now that they're affecting the whole community, we need to revisit this logic. This diff introduces a new approach: 1. The code for determining `memberUserSurfacedPermissions` is removed, in favor of assigning the same set of default user-surfaced permissions to all members, regardless of the community root's `ThreadType`. 2. We also remove a similar distinction in `getRolePermissionBlobs` for announcement subchannels, since they can be handled by the same mechanism that we need to replace point 1 above. 3. Both 1 and 2 are replaced with logic in `p`makePermissionLookup`sBlob`, where we subtract a set of permissions for announcement threads where the user doesn't have `VOICED_IN_ANNOUNCEMENT_CHANNELS`. Depends on D13067