Exclude Group SAML from sign in buttons

Also excludes Group SAML from OmniauthCallbacksController methods

ee/app/helpers/ee/auth_helper.rb

@@ -2,6 +2,18 @@ module EE
   module AuthHelper
     extend ::Gitlab::Utils::Override
 
+    GROUP_LEVEL_PROVIDERS = %i(group_saml).freeze
+
+    override :button_based_providers
+    def button_based_providers
+      super - GROUP_LEVEL_PROVIDERS
+    end
+
+    override :providers_for_base_controller
+    def providers_for_base_controller
+      super - GROUP_LEVEL_PROVIDERS
+    end
+
     override :form_based_provider?
     def form_based_provider?(name)
       super || name.to_s == 'kerberos'

ee/changelogs/unreleased/jej-exclude-group-saml-buttons.yml

+---
+title: Exclude GroupSAML from sign in buttons
+merge_request: 5449
+author:
+type: fixed

spec/helpers/auth_helper_spec.rb

@@ -12,6 +12,11 @@ describe AuthHelper do
       expect(helper.button_based_providers).to include(:twitter)
     end
 
+    it 'excludes group_saml' do
+      allow(helper).to receive(:auth_providers) { [:group_saml] }
+      expect(helper.button_based_providers).to eq([])
+    end
+
     it 'returns empty array' do
       allow(helper).to receive(:auth_providers) { [] }
       expect(helper.button_based_providers).to eq([])
@@ -28,6 +33,11 @@ describe AuthHelper do
       allow(helper).to receive(:auth_providers) { [:twitter, :ldapmain] }
       expect(helper.providers_for_base_controller).not_to include(:ldapmain)
     end
+
+    it 'excludes group_saml' do
+      allow(helper).to receive(:auth_providers) { [:group_saml] }
+      expect(helper.providers_for_base_controller).to eq([])
+    end
   end
 
   describe "form_based_providers" do