util.pubsub: Signal that 'persistent-items' is unsupported when disabled XEP-0060 says that this the way to indicate that 'persistent-items' is unsupported, but doesn't explicitly say if it being disabled in the node configuration also counts as unsupported.

author: Kim Alvefur <zash@zash.se>
date: Thu, 22 Jul 2021 19:53:21 +0200
parent: 11715:ddd6e21e58bf
child: 11768:aa6ab07544c2
--- a/plugins/mod_pubsub/pubsub.lib.lua	Wed Jul 21 23:02:25 2021 +0200
+++ b/plugins/mod_pubsub/pubsub.lib.lua	Thu Jul 22 19:53:21 2021 +0200
@@ -32,6 +32,7 @@
 	["internal-server-error"] = { "wait", "internal-server-error" };
 	["precondition-not-met"] = { "cancel", "conflict", nil, "precondition-not-met" };
 	["invalid-item"] = { "modify", "bad-request", "invalid item" };
+	["persistent-items-unsupported"] = { "cancel", "feature-not-implemented", nil, "persistent-items" };
 };
 local function pubsub_error_reply(stanza, error)
 	local e = pubsub_errors[error];