Be more resilient in the case of missing omniauth settings

Should no longer freak out when omniauth settings aren't present in
gitlab.yml. People who aren't using it shouldn't even have to put a
'false' entry in their config for it (and probably wouldn't, after an
upgrade).

config/initializers/1_settings.rb

@@ -121,19 +121,19 @@ class Settings < Settingslogic
     end
     def ldap_enabled?
-      ldap['enabled']
-    rescue
+      ldap && ldap['enabled']
+    rescue Settingslogic::MissingSetting
       false
     end
     def omniauth_enabled?
       omniauth && omniauth['enabled']
-    rescue
+    rescue Settingslogic::MissingSetting
       false
     end
     def omniauth_providers
-      omniauth['providers'] || []
+      (omniauth_enabled? && omniauth['providers']) || []
     end
     def disable_gravatar?

lib/gitlab/auth.rb

@@ -17,7 +17,7 @@ module Gitlab
       end
     end
-    def create_from_omniauth auth, ldap = false
+    def create_from_omniauth(auth, ldap = false)
       provider = auth.provider
       uid = auth.info.uid || auth.uid
       name = auth.info.name.force_encoding("utf-8")
@@ -39,7 +39,7 @@ module Gitlab
         password_confirmation: password,
         projects_limit: Gitlab.config.default_projects_limit,
       )
-      if Gitlab.config.omniauth.block_auto_created_users && !ldap
+      if Gitlab.config.omniauth['block_auto_created_users'] && !ldap
         @user.blocked = true
       end
       @user.save!
@@ -52,7 +52,7 @@ module Gitlab
       if @user = User.find_by_provider_and_extern_uid(provider, uid)
         @user
       else
-        if Gitlab.config.omniauth.allow_single_sign_on
+        if Gitlab.config.omniauth['allow_single_sign_on']
           @user = create_from_omniauth(auth)
           @user
         end

spec/lib/auth_spec.rb

@@ -4,6 +4,8 @@ describe Gitlab::Auth do
   let(:gl_auth) { Gitlab::Auth.new }
   before do
+    Gitlab.config.stub(omniauth: {})
+
     @info = mock(
       uid: '12djsak321',
       name: 'John',
@@ -64,7 +66,7 @@ describe Gitlab::Auth do
     end
     it "should create user if single_sing_on"do
-      Gitlab.config.omniauth.stub allow_single_sign_on: true
+      Gitlab.config.omniauth['allow_single_sign_on'] = true
       User.stub find_by_provider_and_extern_uid: nil
       gl_auth.should_receive :create_from_omniauth
       gl_auth.find_or_new_for_omniauth(@auth)