Fatal Warning discarded non-unit value

[rbscgh]

Hey folks my projects run with fatal warnings with Wvalue-discard and parseFrom uses builders which produce warning/errors under scala 3 like

[error] 226 |          _unknownFields__.parseField(tag, _input__)
[error]     |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]     |discarded non-Unit value of type scala.collection.mutable.ReusableBuilder[
[error]     |  Long & (com.google.protobuf.ByteString & Int), Vector[Long] | (
[error]     |  Vector[com.google.protobuf.ByteString] | Vector[Int])]

on lines like

        case tag =>
          if (_unknownFields__ == null) {
            _unknownFields__ = new _root_.scalapb.UnknownFieldSet.Builder()
          }
          _unknownFields__.parseField(tag, _input__)

i can silence the error like
scalacOptions ++= Seq("-Wconf:id=175:i,any:v")

but id rather not - anyone else faced this before ?

most likely adding something like

_unknownFields__.parseField(tag, _input__)
() // explicit unit

to the end of these generated builder calls would be the correct fix

[rbscgh]

for example here

ScalaPB/scalapb-runtime/src/main/scalajvm/com/google/protobuf/wrappers/Int64Value.scala

Line 96 in 79df51c

_unknownFields__.parseField(tag, _input__)

would need to be updated for all XValue types.. wdyt @thesamet ?

[steinybot]

Another workaround:

            Compile / PB.generate ~= { files =>
                files.filter(_.isFile).foreach { file =>
                    val fileContent = IO.read(file)
                    val updatedContent = fileContent.replace(
                        "_unknownFields__.parseField(tag, _input__)",
                        "_unknownFields__.parseField(tag, _input__): Unit"
                    )
                    IO.write(file, updatedContent)
                }
                files
            },