How can I migrate from avro4s 3.0.4 to 4.0.0-RC2?

Question

How can I migrate from avro4s 3.0.4 to 4.0.0-RC2? I have the following compiling errors:

[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/AvroFormatImplicits.scala:8:15: value const is not a member of object com.sksamuel.avro4s.SchemaFor
[error]     SchemaFor.const(new Schema.Parser().parse(getClass.getResourceAsStream(hasSchema.resourcePath)))
[error]               ^
[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/AvroFormatImplicits.scala:11:26: not enough arguments for method apply: (implicit evidence$1: com.sksamuel.avro4s.Encoder[T], implicit evidence$2: com.sksamuel.avro4s.Decoder[T])com.sksamuel.avro4s.RecordFormat[T] in object RecordFormat.
[error] Unspecified value parameter evidence$2.
[error]     RecordFormat.apply[T](AvroSchema[T](readSchema))
[error]                          ^
[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/SerdeProvider.scala:29:37: org.apache.avro.Schema does not take parameters
[error]     val schema = SchemaFor[T].schema(DefaultFieldMapper)
[error]                                     ^
[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/SerdeProvider.scala:37:70: no arguments allowed for nullary method build: ()com.sksamuel.avro4s.AvroOutputStream[T]
[error]             val os     = AvroOutputStream.binary[T].to(output).build(schema)
[error]                                                                      ^
[error] four errors found
[error] (Compile / compileIncremental) Compilation failed
[error] Total time: 17 s, completed 28-Jul-2020 19:42:21
[IJ]sbt:global-topic-conveyor> 

Answer 1

First of all, you can always follow the changes at avro4s github repository. Furthermore, you can see the specific changes made between the versions you specified.

You did not attach any source code, so I'll try to address your failures as I can understand them from your failures.

1. SchemaFor.const was removed at version 3.0.5 . You can see that in the diff between the versions. Assuming you had Schema s, and you initiated so far the SchemaFor.const(s), Now you'll need to initiate it: SchemaFor(s). The default fieldMapper will be used. You can see it here.
2. RecordFormat does not take arguments anymore. Therefore assuming you had a type T, that was applied at RecordFormat.apply[T](AvroSchema[T](readSchema)), you need to change it into: RecordFormat[T].
3. Very similar to number 1. SchemaFor.schema was removed. Instead, you can just do: SchemaFor[T].schema. Schema does not take parameters anymore, so you cannot call it with parentheses.
4. AvroOutputStream.build used to take a schema as a parameter. It doesn't take it anymore. You need to change AvroOutputStream.binary[T].to(output).build(schema) into: AvroOutputStream.binary[T].to(output).build()