When generating with a target language of “scala” (the default), scrooge will first look for and use a “scala” namespace declaration. If no scala namespace is specified, scrooge will then fall back to any “java” namespace declaration, and lastly to the catch-all “*” namespace.

Apache’s thrift generator, prior to version 0.9, will actually abort with a parse error if it encounters a “scala” namespace declaration (or for any language but a few known languages that it supports). This means that adding a “scala” namespace declaration to your thrift file, while optimal for scrooge users, will render your thrift file unparseable by many versions of apache’s thrift generator.

To allow for backwards-compatibility with Apache’s thrift generator, scrooge supports a special comment-based namespace declaration that Apache’s thrift generator will ignore. To use this syntax, use the line comment character ‘#’, immediately followed by ‘@’. Apache’s thrift generator will treat the remaining text as a line comment, but scrooge will interpret any following namespace declaration as if not commented-out. For example:

namespace java com.twitter.tweetservice.thriftjava
#@namespace scala com.twitter.tweetservice.thriftscala