Handle LDAP missing credentials error with a flash message.

If a user fails to provide a username or password to the LDAP login
form then a 500 error is returned due to an exception being raised
in omniauth-ldap. This gem has been amended to use the omniauth
error propagation function (fail!) to pass this exception message to
the registered omniauth failure handler so that the Rails application
can handle it approriately.

The failure function now knows about standard exceptions and no longer
requires a specific check for the OmniAuth::Error exception added by
commit f322975c.

This resolves issue #1077.
Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>

Gemfile

@@ -13,7 +13,7 @@ gem "devise", "~> 2.1.0"
 gem "grit",          :git => "https://github.com/gitlabhq/grit.git",            :ref => "7f35cb98ff17d534a07e3ce6ec3d580f67402837"
 gem "gitolite",      :git => "https://github.com/gitlabhq/gitolite-client.git", :ref => "9b715ca8bab6529f6c92204a25f84d12f25a6eb0"
 gem "pygments.rb",   :git => "https://github.com/gitlabhq/pygments.rb.git",     :ref => "2cada028da5054616634a1d9ca6941b65b3ce188"
-gem "omniauth-ldap", :git => "https://github.com/gitlabhq/omniauth-ldap.git",   :ref => "7edf27d0281e09561838122982c16b7e62181f44"
+gem "omniauth-ldap", :git => "https://github.com/gitlabhq/omniauth-ldap.git",   :ref => "f038dd852d7bd473a557e385d5d7c2fd5dc1dc2e"
 gem 'yaml_db',       :git => "https://github.com/gitlabhq/yaml_db.git"
 gem 'grack',         :git => "https://github.com/gitlabhq/grack.git"
 gem "linguist", "~> 1.0.0", :git => "https://github.com/gitlabhq/linguist.git"

Gemfile.lock

@@ -42,8 +42,8 @@ GIT
 
 GIT
   remote: https://github.com/gitlabhq/omniauth-ldap.git
-  revision: 7edf27d0281e09561838122982c16b7e62181f44
-  ref: 7edf27d0281e09561838122982c16b7e62181f44
+  revision: f038dd852d7bd473a557e385d5d7c2fd5dc1dc2e
+  ref: f038dd852d7bd473a557e385d5d7c2fd5dc1dc2e
   specs:
     omniauth-ldap (1.0.2)
       net-ldap (~> 0.2.2)

app/controllers/omniauth_callbacks_controller.rb

@@ -3,13 +3,10 @@ class OmniauthCallbacksController < Devise::OmniauthCallbacksController
   # Extend the standard message generation to accept our custom exception
   def failure_message
     exception = env["omniauth.error"]
-    if exception.class == OmniAuth::Error
-      error = exception.message
-    else
     error   = exception.error_reason if exception.respond_to?(:error_reason)
     error ||= exception.error        if exception.respond_to?(:error)
+    error ||= exception.message      if exception.respond_to?(:message)
     error ||= env["omniauth.error.type"].to_s
-    end
     error.to_s.humanize if error
   end