Failure when compiling with file_descriptor_set

[gwik]

Hi,

I have a failure compiling some protos with buf:

version: v1
plugins:
  - plugin: prost
    out: gen
    opt:
      - bytes=.
      - compile_well_known_types
      - extern_path=.google.protobuf=::pbjson_types
      - file_descriptor_set

Failure: plugin prost: envoy.service.auth.v2alpha.rs: does not exist

I'm using prost plugin compiled from main (44d3fc3).

The failure happens because the prost code generation might omit empty files but the file_descriptor_set option makes it needed. Removing file_descriptor_set makes it work.

The problem starts with commit 038cd34 when prost-build crate was upgraded.

I have a draft PR that fixes the issue, but I don't think it should be merged as is:

34c2ac3

[gwik]

Wondering if this is related.

#56

[neoeinstein]

Thanks for the report and the bisect to find the introducing commit. I'll take a further look here over the weekend. Is there a public set of protos that I can use to reproduce this? (perhaps the Envoy Service protobuf you mentioned works as a repro?)

[gwik]

Yes envoy service proto work as a repro.

See https://github.com/gwik/envoy-prost-tonic

git clone [email protected]:gwik/envoy-prost-tonic
make buf_gen

Failure: plugin prost: envoy.service.auth.v2alpha.rs: does not exist
make: *** [Makefile:6: buf_gen] Error 1