fix: add guard to ensure CAPISTRANO::VERSION is defined (#984)

lib/rollbar/capistrano_tasks.rb

@@ -64,7 +64,11 @@ def deploy_update(capistrano, logger, dry_run, opts = {})
  end
 
  def capistrano_300_warning(logger)
- logger.warn("You need to upgrade capistrano to '>= 3.1' version in order to correctly report deploys to Rollbar. (On 3.0, the reported revision will be incorrect.)") if ::Capistrano::VERSION =~ /^3\.0/
+ return unless ::Capistrano.const_defined?('VERSION') && ::Capistrano::VERSION =~ /^3\.0/
+
+ logger.warn('You need to upgrade capistrano to >= 3.1 version in order'\
+ 'to correctly report deploys to Rollbar. (On 3.0, the reported revision'\
+ 'will be incorrect.)')
  end
 
  def report_deploy_started(capistrano, dry_run)

spec/rollbar/capistrano_tasks_spec.rb

@@ -326,4 +326,44 @@
  end
  end
  end
+
+ describe '.capistrano_300_warning' do
+ context 'when ::Capistrano::VERSION is defined' do
+ it 'does nothing' do
+ expect(logger).not_to receive(:warn)
+
+ subject.send(:capistrano_300_warning, logger)
+ end
+ end
+
+ context 'when ::Capistrano::VERSION is 3.0' do
+ it 'logs a warning' do
+ # The class is not reloaded between tests, so prepare to restore the constant.
+ original_version = ::Capistrano::VERSION
+ ::Capistrano.send(:remove_const, 'VERSION')
+ ::Capistrano.const_set('VERSION', '3.0.0')
+
+ expect(logger).to receive(:warn)
+
+ subject.send(:capistrano_300_warning, logger)
+
+ ::Capistrano.send(:remove_const, 'VERSION')
+ ::Capistrano.const_set('VERSION', original_version)
+ end
+ end
+
+ context 'when ::Capistrano::VERSION is undefined' do
+ it 'does nothing' do
+ # The class is not reloaded between tests, so prepare to restore the constant.
+ original_version = ::Capistrano::VERSION
+ ::Capistrano.send(:remove_const, 'VERSION')
+
+ expect(logger).not_to receive(:warn)
+
+ subject.send(:capistrano_300_warning, logger)
+
+ ::Capistrano.const_set('VERSION', original_version)
+ end
+ end
+ end
 end