FIX: Group can't be deleted if certain users are demoted.

app/models/group_user.rb

@@ -82,15 +82,8 @@ class GroupUser < ActiveRecord::Base
       .includes(:group)
       .maximum("groups.grant_trust_level")
 
-    if highest_level.nil?
-      # If the user no longer has a group with a trust level,
-      # unlock them, start at 0 and consider promotions.
-      user.update!(group_locked_trust_level: nil)
-      Promotion.recalculate(user)
-    else
     user.update!(group_locked_trust_level: highest_level)
-      user.change_trust_level!(highest_level)
+    Promotion.recalculate(user)
-    end
   end
 
 end

lib/promotion.rb

@@ -111,16 +111,16 @@ class Promotion
   def self.recalculate(user, performed_by = nil)
     # First, use the manual locked level
     unless user.manual_locked_trust_level.nil?
-      user.trust_level = user.manual_locked_trust_level
+      return user.update!(
-      user.save
+        trust_level: user.manual_locked_trust_level
-      return
+      )
     end
 
     # Then consider the group locked level
     if user.group_locked_trust_level
-      user.trust_level = user.group_locked_trust_level
+      return user.update!(
-      user.save
+        trust_level: user.group_locked_trust_level
-      return
+      )
     end
 
     user.update_column(:trust_level, TrustLevel[0])

spec/models/group_spec.rb

@@ -541,6 +541,7 @@ describe Group do
     end
   end
 
+  describe 'trust level management' do
     it "correctly grants a trust level to members" do
       group = Fabricate(:group, grant_trust_level: 2)
       u0 = Fabricate(:user, trust_level: 0)
@@ -553,6 +554,37 @@ describe Group do
       expect(u3.reload.trust_level).to eq(3)
     end
 
+    describe 'when a user has qualified for trust level 1' do
+      let(:user) do
+        Fabricate(:user,
+          trust_level: 1,
+          created_at: Time.zone.now - 10.years
+        )
+      end
+
+      let(:group) { Fabricate(:group, grant_trust_level: 1) }
+      let(:group2) { Fabricate(:group, grant_trust_level: 0) }
+
+      before do
+        user.user_stat.update!(
+          topics_entered: 999,
+          posts_read_count: 999,
+          time_read: 999
+        )
+      end
+
+      it "should not demote the user" do
+        group.add(user)
+        group2.add(user)
+
+        expect(user.reload.trust_level).to eq(1)
+
+        group.remove(user)
+
+        expect(user.reload.trust_level).to eq(0)
+      end
+    end
+
     it "adjusts the user trust level" do
       g0 = Fabricate(:group, grant_trust_level: 2)
       g1 = Fabricate(:group, grant_trust_level: 3)
@@ -586,6 +618,7 @@ describe Group do
       expect(user.group_locked_trust_level).to be_nil
       expect(user.trust_level).to eq(0)
     end
+  end
 
   it 'should cook the bio' do
     group = Fabricate(:group)