Correctly handle data-loss scenarios when encrypting columns

If the EncryptColumns background migration runs in a sidekiq with a
stale view of the database schema, or when the purported destination
columns don't actually exist, data loss can result. Attempt to work
around these issues by reloading schema information before running
the migration, and raising errors if the model reports that any of its
source or destination columns are missing.

1 files changed, 30 insertions, 0 deletions

diff --git a/spec/initializers/attr_encrypted_no_db_connection_spec.rb b/spec/initializers/attr_encrypted_no_db_connection_spec.rb
new file mode 100644
index 00000000000..2da9f1cbd96
--- /dev/null
+++ b/spec/initializers/attr_encrypted_no_db_connection_spec.rb
@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+describe 'GitLab monkey-patches to AttrEncrypted' do
+  describe '#attribute_instance_methods_as_symbols_available?' do
+    it 'returns false' do
+      expect(ActiveRecord::Base.__send__(:attribute_instance_methods_as_symbols_available?)).to be_falsy
+    end
+
+    it 'does not define virtual attributes' do
+      klass = Class.new(ActiveRecord::Base) do
+        # We need some sort of table to work on
+        self.table_name = 'projects'
+
+        attr_encrypted :foo
+      end
+
+      instance = klass.new
+
+      aggregate_failures do
+        %w[
+          encrypted_foo encrypted_foo=
+          encrypted_foo_iv encrypted_foo_iv=
+          encrypted_foo_salt encrypted_foo_salt=
+        ].each do |method_name|
+          expect(instance).not_to respond_to(method_name)
+        end
+      end
+    end
+  end
+end