ui_init: Fix "Error: Unknown user_id in get_by_user_id: 0".

For spectators (logged view), we send user_id=0 via page_params.

The people module does not know about this user ID, and so throws the
exception. Earlier `people.get_by_user_id` was not called on page load,
but only when determining settings permissions with `settings_data.user_has_permission`.

But 231c536cad made it so that that function
is always called, so we need to handle the spectator case explicitly.

Co-authored-by: Gaurav Pandey <gauravguitarrocks@gmail.com>

frontend_tests/node_tests/settings_data.js

@@ -147,6 +147,13 @@ function test_policy(label, policy, validation_func) {
         page_params.is_guest = false;
         assert.equal(validation_func(), true);
 
+        page_params.is_spectator = true;
+        page_params[policy] = settings_config.common_policy_values.by_members.code;
+        assert.equal(validation_func(), false);
+
+        page_params.is_spectator = false;
+        assert.equal(validation_func(), true);
+
         page_params[policy] = settings_config.common_policy_values.by_full_members.code;
         page_params.user_id = 30;
         isaac.date_joined = new Date(Date.now());

static/js/settings_data.js

@@ -3,6 +3,7 @@ import * as settings_config from "./settings_config";
 
 let user_join_date;
 export function initialize(current_user_join_date) {
+    // We keep the `user_join_date` as the present day's date if the user is a spectator
     user_join_date = current_user_join_date;
 }
 
@@ -105,6 +106,10 @@ function user_has_permission(policy_value) {
         return true;
     }
 
+    if (page_params.is_spectator) {
+        return false;
+    }
+
     if (page_params.is_guest) {
         return false;
     }

static/js/ui_init.js

@@ -499,7 +499,18 @@ export function initialize_everything() {
     popover_menus.initialize();
 
     people.initialize(page_params.user_id, people_params);
-    settings_data.initialize(people.get_by_user_id(page_params.user_id).date_joined);
+
+    let date_joined;
+    if (!page_params.is_spectator) {
+        const user = people.get_by_user_id(page_params.user_id);
+        date_joined = user.date_joined;
+    } else {
+        // Spectators don't have an account, so we just prevent their
+        // date_joined is now.
+        date_joined = new Date();
+    }
+
+    settings_data.initialize(date_joined);
 
     // These components must be initialized early, because other
     // modules' initialization has not been audited for whether they