Is it a breaking change if I move a Thrift data structure from one file to another?

Question

If I have a service-specific file with Thrift definitions named serviceA.thrift:

struct ServiceError {
  1: required i16 code,
  2: required string message
}

struct Service Response {
  1: optional ServiceError error;
  ...
}

and want to move the definition of ServiceError to a separate file named common.thrift so it can be used in different services:

struct ServiceError {
  1: required i16 code,
  2: required string message
}

would it be a breaking change to update serviceA.thrift to use the new shared data structure:

include "common.thrift"

struct Service Response {
  1: optional common.ServiceError error;
  ...
}

?

Answer 1

Since the wire format only knows numeric IDs¹⁾ which you don't change that should work seamlessly.

---

^{1) only exception to that rule are service method names}