Changes announced February 5, 2024

Changes announced for Protocol Buffers on February 5, 2024.

This topic covers breaking changes in Java, C++, and Python in the 26.x line.

JSON Formatter Option Changes

Starting in the 26.x line, the JSON formatter option to print default-valued fields is replaced with a fixed way to handle proto2 and proto3 optional fields consistently.

Java: includingDefaultValueFields() is replaced with alwaysPrintFieldsWithNoPresence().
C++: always_print_default_values is replaced with always_print_fields_with_no_presence=True.
Py: including_default_value_fields=True is replaced with always_print_fields_with_no_presence=True.

The new flag behaves identically to the old flag on proto3 messages, but no longer applies to proto2 optional fields. The old flags applied to proto2 optional fields but not proto3 optional fields.