Based on feedback from @iNPUTmice, no need to check for PEP support

Since you can still start OMEMO sessions with contacts without it, they
just can't create sessions with you.

spec/omemo.js

@@ -59,30 +59,10 @@
 
             test_utils.waitUntil(function () {
                 return _.filter(_converse.connection.IQ_stanzas, function (iq) {
-                    const node = iq.nodeTree.querySelector('iq[to="dummy@localhost"] query[xmlns="http://jabber.org/protocol/disco#info"]');
+                    const node = iq.nodeTree.querySelector('publish[node="eu.siacs.conversations.axolotl.bundles:31415"]');
                     if (node) { iq_stanza = iq.nodeTree; }
                     return node;
-                }).length > 0;
-            }, 1000).then(function () {
-                /* PEP support is prerequisite for OMEMO */
-                const stanza = $iq({
-                    'type': 'result',
-                    'from': 'dummy@localhost',
-                    'to': 'dummy@localhost/resource',
-                    'id': iq_stanza.getAttribute('id'),
-                }).c('query', {'xmlns': 'http://jabber.org/protocol/disco#info'})
-                    .c('identity', {
-                        'category': 'pubsub',
-                        'type': 'pep'});
-                _converse.connection._dataRecv(test_utils.createRequest(stanza));
-
-                return test_utils.waitUntil(() => {
-                    return _.filter(_converse.connection.IQ_stanzas, function (iq) {
-                        const node = iq.nodeTree.querySelector('publish[node="eu.siacs.conversations.axolotl.bundles:31415"]');
-                        if (node) { iq_stanza = iq.nodeTree; }
-                        return node;
-                    }).length;
-                });
+                }).length;
             }).then(function () {
                 expect(iq_stanza.getAttributeNames().sort().join()).toBe(["from", "type", "xmlns", "id"].sort().join());
                 expect(iq_stanza.querySelector('prekeys').childNodes.length).toBe(100);

src/converse-omemo.js

@@ -49,12 +49,6 @@
         });
     }
 
-    function serverHasOMEMOSupport (_converse) {
-        return new Promise((resolve, reject) => {
-            _converse.api.disco.getIdentity('pubsub', 'pep', _converse.bare_jid)
-                .then((identity) => resolve(!_.isNil(identity)));
-        });
-    }
 
     converse.plugins.add('converse-omemo', {
 
@@ -65,7 +59,6 @@
         dependencies: ["converse-chatview"],
 
         overrides: {
-
             ChatBoxView:  {
                 events: {
                     'click .toggle-omemo': 'toggleOMEMO'
@@ -74,23 +67,6 @@
                 toggleOMEMO (ev) {
                     // TODO:
                     ev.preventDefault();
-                },
-
-                addOMEMOToolbarButton () {
-                    const { _converse } = this.__super__,
-                          { __ } = _converse;
-                    Promise.all([
-                        contactHasOMEMOSupport(_converse, this.model.get('jid')),
-                        serverHasOMEMOSupport(_converse)
-                    ]).then((support) => {
-                        const client_supports = support[0],
-                              server_supports = support[1];
-                        if (client_supports && server_supports) {
-                            this.el.querySelector('.chat-toolbar').insertAdjacentHTML(
-                                'beforeend',
-                                tpl_toolbar_omemo({'__': __}));
-                        }
-                    }).catch(_.partial(_converse.log, _, Strophe.LogLevel.ERROR));
                 }
             }
         },
@@ -268,6 +244,8 @@
             }
 
             function updateDevicesFromStanza (stanza) {
+                // TODO: check whether our own device_id is still on the list,
+                // otherwise we need to update it.
                 const device_ids = _.map(
                     sizzle(`items[node="${Strophe.NS.OMEMO_DEVICELIST}"] item[xmlns="${Strophe.NS.OMEMO}"] device`, stanza),
                     (device) => device.getAttribute('id'));
@@ -289,7 +267,7 @@
                 // Add a handler for devices pushed from other connected clients
                 _converse.connection.addHandler((message) => {
                     if (message.querySelector('event[xmlns="'+Strophe.NS.PUBSUB+'#event"]')) {
-                        _converse.bookmarks.updateDevicesFromStanza(message);
+                        updateDevicesFromStanza(message);
                     }
                 }, null, 'message', 'headline', null, _converse.bare_jid);
             }
@@ -302,31 +280,33 @@
                 return _converse.omemo_store.fetchSession()
             }
 
-            function initOMEMO () {
-                /* Publish our bundle and then fetch our own device list.
-                 * If our device list does not contain this device's id, publish the
-                 * device list with the id added. Also deduplicate device ids in the list.
-                 */
-                restoreOMEMOSession()
-                    .then(() => publishBundle())
-                    .then(() => updateOwnDeviceList())
-                    .then(() => _converse.emit('OMEMOInitialized'))
-                    .catch(_.partial(_converse.log, _, Strophe.LogLevel.ERROR));
+            function addOMEMOToolbarButton (view) {
+                const { __ } = _converse;
+                contactHasOMEMOSupport(_converse, view.model.get('jid')).then((support) => {
+                    if (support) {
+                        view.el.querySelector('.chat-toolbar').insertAdjacentHTML(
+                            'beforeend',
+                            tpl_toolbar_omemo({'__': __}));
+                    }
+                }).catch(_.partial(_converse.log, _, Strophe.LogLevel.ERROR));
             }
 
-            function onStatusInitialized () {
+            function initOMEMO() {
                 _converse.devicelists = new _converse.DeviceLists();
                 _converse.devicelists.browserStorage = new Backbone.BrowserStorage.session(
                     b64_sha1(`converse.devicelists-${_converse.bare_jid}`)
                 );
-
-                initOMEMO();
+                restoreOMEMOSession()
+                    .then(() => publishBundle())
+                    .then(() => updateOwnDeviceList())
+                    .then(() => _converse.emit('OMEMOInitialized'))
+                    .catch(_.partial(_converse.log, _, Strophe.LogLevel.ERROR));
             }
 
-            _converse.api.listen.on('renderToolbar', (view) => view.addOMEMOToolbarButton());
-            _converse.api.listen.on('statusInitialized', onStatusInitialized);
-            _converse.api.listen.on('connected', registerPEPPushHandler);
             _converse.api.listen.on('afterTearDown', () => _converse.devices.reset());
+            _converse.api.listen.on('connected', registerPEPPushHandler);
+            _converse.api.listen.on('renderToolbar', addOMEMOToolbarButton);
+            _converse.api.listen.on('statusInitialized', initOMEMO);
             _converse.api.listen.on('addClientFeatures',
                 () => _converse.api.disco.own.features.add(Strophe.NS.OMEMO_DEVICELIST+"notify"));
         }