commit 2d79c99583c249567e670b4b9b1978320b259ef1
author Yifei Teng <yifeit@fuchsia.infra.roller.google.com> Fri Feb 12 02:04:04 2021 +0000
committer Copybara-Service <copybara-worker@google.com> Thu Feb 11 18:04:56 2021 -0800
tree 82c20ad4b15b01923b69eace1bd4f91577f2a31e
parent 65298df5eafd7b628d1e2e913196b6384da68b6a

[roll] Roll fuchsia [fidl][llcpp] Deprecate RawChannelInterface and introduce allow-list

This CL adds a `soft_migration.h` header which we could use to deprecate
various LLCPP APIs and migrate targets individually, using an
allow-list as backstop against new dependencies on the API. The
allow-list allows a certain user GN target to import a C macro that
suppresses the deprecation warning on the API. I removed the global
`-Wno-deprecated-declaration` suppression in a previous change, which
allows usage of deprecated API to produce build-time warnings.

In the case of RawChannelInterface:
- RawChannelInterface is annotated with FIDL_DEPRECATED_USE_TYPED_CHANNELS.
- FIDL_DEPRECATED_USE_TYPED_CHANNELS expands to a C++ [[deprecated]]
attribute when FIDL_LLCPP_ALLOW_DEPRECATED_RAW_CHANNELS is not defined.
- FIDL_LLCPP_ALLOW_DEPRECATED_RAW_CHANNELS is defined by the
`//build/cpp:fidl-llcpp-deprecated-raw-channels` GN config, which has
restricted visibility.

How I arrived at this CL:

- Add the deprecation warnings in RawChannelInterface.
- Run `scripts/gn/suppress_errors.py --warning RawChannelInterface --config='//build/cpp:fidl-llcpp-deprecated-raw-channels' --confirm --complete --comment "TODO(fxbug.dev/69585): Migrate to LLCPP typed channels"`
using the script from I09dcdf4da0a1d7b2208910a7f0208fb74f927d83.
- Change some of the `configs` to `public_configs`, because the
deprecation suppression macros need to be propagated to downstream
targets if the offending deprecated usage is within a header.
- Occassionally, use the script to add the
`fidl-llcpp-deprecated-raw-channels` config to a target containing the
`.cc` file instead, because some deprecated usage come from headers
that are not tracked by our build system (i.e. never appear anywhere
in GN files) :/

In the next CLs, we would be able to expand the allow-list to cover the
deprecation of various implicit conversion in ClientEnd/ServerEnd.

TEST:
- Remove a `fidl-llcpp-deprecated-raw-channels` config somewhere,
`fx build`, and then observe warnings.
- Manually inspect some targets with that config, and confirm that they
indeed use the RawChannelInterface API.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/483590
Original-Revision: 6f50ec9445af366116f506b7b06959e4ce5916b5
GitOrigin-RevId: e35b2f6312f82977d3d381dc8a291009897c5dc2
Change-Id: I997dddf149e3f26e6f31ad91e70adcac142ad13a