presence: Avoid checking activity when reloading.

We sometimes get blueslip errors from browsers that are clearly still
attempting to reload long after they should have.  These browsers can
produce a lot of unnecessary presence update exceptions.

To solve that, we start checking reload_in_progress in the presence
code path.

While we're at it, we also add some blueslip logging for the reload
code path, in case it becomes useful when debugging future issues.

frontend_tests/node_tests/activity.js

@@ -39,6 +39,13 @@ zrequire('presence');
 zrequire('people');
 zrequire('activity');
 
+set_global('blueslip', {
+    log: function () {},
+});
+
+set_global('reload', {
+    is_in_progress: function () {return false;},
+});
 set_global('resize', {
     resize_page_components: function () {},
 });
@@ -706,4 +713,11 @@ $('.user-list-filter').is = function (sel) {
   assert($('#zephyr-mirror-error').hasClass('show'));
   assert(!activity.new_user_input);
   assert(!activity.has_focus);
+
+  // Now execute the reload-in-progress code path
+  reload.is_in_progress = function () {
+      return true;
+  };
+  activity.initialize();
+
 }());

static/js/activity.js

@@ -399,8 +399,11 @@ exports.update_huddles = function () {
     exports.update_scrollbar.group_pms();
 };
 
-
 function focus_ping(want_redraw) {
+    if (reload.is_in_progress()) {
+        blueslip.log("Skipping querying presence because reload in progress");
+        return;
+    }
     channel.post({
         url: '/json/users/me/presence',
         data: {status: (exports.has_focus) ? exports.ACTIVE : exports.IDLE,

static/js/reload.js

@@ -175,7 +175,10 @@ exports.initialize = function reload__initialize() {
 };
 
 function do_reload_app(send_after_reload, save_pointer, save_narrow, save_compose, message) {
-    if (reload_in_progress) { return; }
+    if (reload_in_progress) {
+        blueslip.log("do_reload_app: Doing nothing since reload_in_progress");
+        return;
+    }
 
     // TODO: we should completely disable the UI here
     if (save_pointer || save_narrow || save_compose) {
@@ -305,6 +308,7 @@ window.addEventListener('beforeunload', function () {
     // When that happens we reload the page to correct the problem. If this
     // happens before the navigation is complete the user is kept captive at
     // zulip.
+    blueslip.log("Setting reload_in_progress in beforeunload handler");
     reload_in_progress = true;
 });
 

static/js/server_events.js

@@ -270,6 +270,7 @@ exports.cleanup_event_queue = function cleanup_event_queue() {
     if (page_params.event_queue_expired === true) {
         return;
     }
+    blueslip.log("Cleaning up our event queue");
     // Set expired because in a reload we may be called twice.
     page_params.event_queue_expired = true;
     channel.del({