From 865cb3feb9dee7df19083b22592b5cbfe6b2f245 Mon Sep 17 00:00:00 2001
From: Osama Sayegh <asooomaasoooma90@gmail.com>
Date: Fri, 10 Aug 2018 14:12:02 +0300
Subject: [PATCH] FIX: allow selecting site's default theme from preference

---
 app/services/user_updater.rb       |  1 +
 lib/guardian.rb                    |  2 ++
 spec/services/user_updater_spec.rb | 23 +++++++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/app/services/user_updater.rb b/app/services/user_updater.rb
index a580e968da6..de238e50ec0 100644
--- a/app/services/user_updater.rb
+++ b/app/services/user_updater.rb
@@ -88,6 +88,7 @@ class UserUpdater
     # special handling for theme_id cause we need to bump a sequence number
     if attributes.key?(:theme_ids)
       user_guardian = Guardian.new(user)
+      attributes[:theme_ids].reject!(&:blank?)
       attributes[:theme_ids].map!(&:to_i)
       if user_guardian.allow_themes?(attributes[:theme_ids])
         user.user_option.theme_key_seq += 1 if user.user_option.theme_ids != attributes[:theme_ids]
diff --git a/lib/guardian.rb b/lib/guardian.rb
index db7d168428a..30bf87acd4d 100644
--- a/lib/guardian.rb
+++ b/lib/guardian.rb
@@ -359,6 +359,8 @@ class Guardian
   end
 
   def allow_themes?(theme_ids)
+    return true if theme_ids.blank?
+
     if is_staff? && (theme_ids - Theme.theme_ids).blank?
       return true
     end
diff --git a/spec/services/user_updater_spec.rb b/spec/services/user_updater_spec.rb
index 47e37edc0d0..34daad1b64b 100644
--- a/spec/services/user_updater_spec.rb
+++ b/spec/services/user_updater_spec.rb
@@ -129,6 +129,29 @@ describe UserUpdater do
       expect(user.user_option.mailing_list_mode).to eq true
     end
 
+    it "filters theme_ids blank values before updating perferences" do
+      user = Fabricate(:user)
+      user.user_option.update!(theme_ids: [1])
+      updater = UserUpdater.new(acting_user, user)
+
+      updater.update(theme_ids: [""])
+      user.reload
+      expect(user.user_option.theme_ids).to eq([])
+
+      updater.update(theme_ids: [nil])
+      user.reload
+      expect(user.user_option.theme_ids).to eq([])
+
+      theme = Fabricate(:theme)
+      child = Fabricate(:theme)
+      theme.add_child_theme!(child)
+      theme.set_default!
+
+      updater.update(theme_ids: [theme.id.to_s, child.id.to_s, "", nil])
+      user.reload
+      expect(user.user_option.theme_ids).to eq([theme.id, child.id])
+    end
+
     context 'when sso overrides bio' do
       it 'does not change bio' do
         SiteSetting.sso_url = "https://www.example.com/sso"