Fix LDAP config lookup for provider 'ldap'

CHANGELOG

 v 7.4.1
   - Fix LDAP authentication for Git HTTP access
+  - Fix LDAP config lookup for provider 'ldap'
 v 7.4.0
   - Refactored membership logic

lib/gitlab/ldap/config.rb

@@ -16,10 +16,23 @@ module Gitlab
         servers.map {|server| server['provider_name'] }
       end
+      def self.valid_provider?(provider)
+        providers.include?(provider)
+      end
+
+      def self.invalid_provider(provider)
+        raise "Unknown provider (#{provider}). Available providers: #{providers}"
+      end
+
       def initialize(provider)
-        @provider = provider
-        invalid_provider unless valid_provider?
-        @options = config_for(provider)
+        if self.class.valid_provider?(provider)
+          @provider = provider
+        elsif provider == 'ldap'
+          @provider = self.class.providers.first
+        else
+          self.class.invalid_provider(provider)
+        end
+        @options = config_for(@provider) # Use @provider, not provider
       end
       def enabled?
@@ -89,14 +102,6 @@ module Gitlab
         end
       end
-      def valid_provider?
-        self.class.providers.include?(provider)
-      end
-
-      def invalid_provider
-        raise "Unknown provider (#{provider}). Available providers: #{self.class.providers}"
-      end
-
       def auth_options
         {
           auth: {

spec/lib/gitlab/ldap/config_spec.rb

@@ -16,5 +16,19 @@ describe Gitlab::LDAP::Config do
     it "raises an error if a unknow provider is used" do
       expect{ Gitlab::LDAP::Config.new 'unknown' }.to raise_error
     end
+
+    context "if 'ldap' is the provider name" do
+      let(:provider) { 'ldap' }
+
+      context "and 'ldap' is not in defined as a provider" do
+        before { Gitlab::LDAP::Config.stub(providers: %w{ldapmain}) }
+
+        it "uses the first provider" do
+          # Fetch the provider_name attribute from 'options' so that we know
+          # that the 'options' Hash is not empty/nil.
+          expect(config.options['provider_name']).to eq('ldapmain')
+        end
+      end
+    end
   end
-end
\ No newline at end of file
+end