pants-proto-test

Test of pants protobuf code generation with Python and Java

Overview: We are trying to build a schema registry (collection of .proto files) and build packages of the compiled objects in both Python and Java. We need these packages to be available outside the repo, so we are using python_distribution and deploy_jar.

The problem: We can make either of the packages work independnently. If we exclude pants.backend.codegen.protobuf.python from the backends (and remove the Python package), then the Java package compiles correctly and includes everything expected - compiled protobuf as well as the com.google.protobuf library.

However, when we include both Python and Java codegen, we become unable to build the Java package, with this error:

❯ ./pants package schemas/com/example/schemas/v1:schemas_java
09:37:26.00 [INFO] Initializing scheduler...
09:37:27.26 [INFO] Scheduler initialized.
09:37:27.32 [WARN] Please either set `enabled = true` in the [anonymous-telemetry] section of pants.toml to enable sending anonymous stats to the Pants project to aid development, or set `enabled = false` to disable it. No telemetry sent for this run. An explicit setting will get rid of this message. See https://www.pantsbuild.org/v2.15/docs/anonymous-telemetry for details.
09:37:29.14 [ERROR] 1 Exception encountered:

Engine traceback:
  in `package` goal
  in Compile with javac
  in Compile with javac
  in Compile with javac
  in Compile with javac

ClasspathSourceMissing: No JVM classpath providers (from: CompileJavaSourceRequest, CoursierFetchRequest, DeployJarClasspathEntryRequest, JvmResourcesRequest) were compatible with the combination of inputs:
  * 3rdparty/python:reqs#protobuf       (python_requirement)

Separately, in both cases, we cannot import the package in /schemas from another root, but I assume this is me doing something wrong.

Another oddity is that with both codegen backends, when we do ./pants export-codegen ::, only the Java is exported:

❯ tree dist/codegen
dist/codegen
└── schemas
    └── com
        └── example
            └── schemas
                └── v1
                    └── PersonOuterClass.java

5 directories, 1 file