tree e3589b9b6a54c19d52b0d7428e0d392b9ca3d677
parent 192907f11d0b5b07e51d648a62ccde44304c3a96
author Tom Craig <tommycraig@gmail.com> 1674624246 +0000
committer CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com> 1674624246 +0000

pw_protobuf: Codegen kConstantCase field enums

pw_protobuf generated code includes an "enum class Fields : uint32_t"
type in in message, with values equal to the IDs for each field in the
message.

Unfortunately, the existing generated code uses SNAKE_CASE for the
names, rather than kConstantCase. In addition to be against the
style guide, this makes collisions with legacy C macros much more
likely.

Indeed, I ran into this issue due to a naming collison on OUTPUT_TYPE
between stm32cube.h and descriptor.pwpb.h. Of course, ST deserves
significant blame here for using inadequately namespaced global
identifiers... it's not just pw_protobuf's fault for not using
kConstantCase.

This commit does not yet migrate pigweed code to use the kConstantCase
values, that will be in an immediate follow-on. However, this commit
DOES add a GN variable to control generation of the legacy
names (in addition to new names):
    pw_protobuf_compiler_GENERATE_LEGACY_ENUM_SNAKE_CASE_NAMES

This currently defaults to true, but will change to default to false
after the follow-on commit which migrates upstream pigweed away from
SNAKE_CASE. That will have to be done by an upstream pigweed developer.

Bug: b/266298474
Change-Id: I460a7d203905d39d234d3bf1a7621b52b188c109
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/126804
Commit-Queue: Wyatt Hepler <hepler@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>