AIP-203 question: Using IMMUTABLE and OUTPUT_ONLY together

[noahdietz]

Hello @noahdietz

I've been looking for an example when a field reasonably has IMMUTABLE + OUTPUT_ONLY. Unfortunately, didn't find an exhaustive answer.

I think IMMUTABLE + OUTPUT_ONLY conflict when attempting to update the field. Per AIP-203:

• IMMUTABLE requires to throw INVALID_ARGUMENT
• OUTPUT_ONLY requires to ignore the field value in the request

Also it's unclear why fields like create_time are OUTPUT_ONLY but not IMMUTABLE. I guess this timestamp isn't changed normally after the creation.

I've found the discussion #317 (comment) but it may be outdated as the behavior IDENTIFIER appeared in 2023: googleapis/googleapis@f5987af

Am I missing something?

Originally posted by @CuriousStork in #825