Issue #993: Fixed login failure when extern_uid changes

CHANGELOG

@@ -75,6 +75,7 @@ v 7.14.0 (unreleased)
   - Update Flowdock integration to support new Flowdock API (Boyan Tabakov)
   - Remove author from files view (Sven Strickroth)
   - Fix infinite loop when SAML was incorrectly configured.
+  - Fixed login failure when extern_uid changes (Joel Koglin)
 
 v 7.13.5
   - Satellites reverted

app/models/user.rb

@@ -104,7 +104,7 @@ class User < ActiveRecord::Base
   # Profile
   has_many :keys, dependent: :destroy
   has_many :emails, dependent: :destroy
-  has_many :identities, dependent: :destroy
+  has_many :identities, dependent: :destroy, autosave: true
 
   # Groups
   has_many :members, dependent: :destroy

db/migrate/20150817163600_deduplicate_user_identities.rb

@@ -0,0 +1,14 @@
+class DeduplicateUserIdentities < ActiveRecord::Migration
+  def change
+    execute 'DROP TABLE IF EXISTS tt_migration_DeduplicateUserIdentities;'
+    execute 'CREATE TEMPORARY TABLE tt_migration_DeduplicateUserIdentities AS SELECT id,provider,user_id FROM identities;'
+    execute 'DELETE FROM identities WHERE id NOT IN ( SELECT MIN(id) FROM tt_migration_DeduplicateUserIdentities GROUP BY user_id, provider);'
+    execute 'DROP TABLE IF EXISTS tt_migration_DeduplicateUserIdentities;'
+  end
+
+  def down
+    # This is an irreversible migration;
+    # If someone is trying to rollback for other reasons, we should not throw an Exception.
+    # raise ActiveRecord::IrreversibleMigration
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20150812080800) do
+ActiveRecord::Schema.define(version: 20150817163600) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"

lib/gitlab/ldap/user.rb

@@ -44,9 +44,13 @@ module Gitlab
         gl_user.skip_reconfirmation!
         gl_user.email = auth_hash.email
 
-        # Build new identity only if we dont have have same one
-        gl_user.identities.find_or_initialize_by(provider: auth_hash.provider,
-                                                 extern_uid: auth_hash.uid)
+        # If we don't have an identity for this provider yet, create one
+        if gl_user.identities.find_by(provider: auth_hash.provider).nil?
+          gl_user.identities.new(extern_uid: auth_hash.uid, provider: auth_hash.provider)
+        else # Update the UID attribute for this provider in case it has changed
+          identity = gl_user.identities.select { |identity|  identity.provider == auth_hash.provider }
+          identity.first.extern_uid = auth_hash.uid
+        end
 
         gl_user
       end

spec/lib/gitlab/ldap/user_spec.rb

@@ -47,6 +47,28 @@ describe Gitlab::LDAP::User do
       expect(existing_user.ldap_identity.provider).to eql 'ldapmain'
     end
 
+    it 'connects to existing ldap user if the extern_uid changes' do
+      existing_user = create(:omniauth_user, email: 'john@example.com', extern_uid: 'old-uid', provider: 'ldapmain')
+      expect{ ldap_user.save }.not_to change{ User.count }
+
+      existing_user.reload
+      expect(existing_user.ldap_identity.extern_uid).to eql 'my-uid'
+      expect(existing_user.ldap_identity.provider).to eql 'ldapmain'
+      expect(existing_user.id).to eql ldap_user.gl_user.id
+    end
+
+    it 'maintains an identity per provider' do
+      existing_user = create(:omniauth_user, email: 'john@example.com', provider: 'twitter')
+      expect(existing_user.identities.count).to eql(1)
+
+      ldap_user.save
+      expect(ldap_user.gl_user.identities.count).to eql(2)
+
+      # Expect that find_by provider only returns a single instance of an identity and not an Enumerable
+      expect(ldap_user.gl_user.identities.find_by(provider: 'twitter')).to be_instance_of Identity
+      expect(ldap_user.gl_user.identities.find_by(provider: auth_hash.provider)).to be_instance_of Identity
+    end
+
     it "creates a new user if not found" do
       expect{ ldap_user.save }.to change{ User.count }.by(1)
     end