Remove effect covariance as it was affecting 2.12.x

Author: cfernandescaesars

build.sbt

@@ -41,8 +41,8 @@ inThisBuild {
 
 ThisBuild / scalacOptions ++= {
   CrossVersion.partialVersion(scalaVersion.value) match {
-    case Some((2, 12 | 13)) =>
-      Seq(
+    case Some((2, minor @ (12 | 13))) =>
+      val base = Seq(
         "-deprecation",
         "-encoding",
         "UTF-8",
@@ -57,6 +57,8 @@ ThisBuild / scalacOptions ++= {
         "-Ywarn-unused",
         "-Xsource:3"
       )
+      if (minor == 12) "-Ypartial-unification" +: base
+      else base
 
     case Some((3, _)) =>
       Seq.empty

src/main/scala/io/kaizensolutions/jsonschema/JsonSchemaDeserializer.scala

@@ -17,21 +17,23 @@ import scala.reflect.ClassTag
 
 // See AbstractKafkaJsonSchemaDeserializer
 object JsonSchemaDeserializer {
-  def forValue[F[+_]: Sync, A: Decoder](
+  def forValue[F[_]: Sync, A: Decoder](
     settings: JsonSchemaDeserializerSettings,
     client: SchemaRegistryClient
   )(implicit jsonSchema: json.Schema[A], tag: ClassTag[A]): F[ValueDeserializer[F, A]] =
     toJsonSchema[F, A](jsonSchema, settings.jsonSchemaId)
       .flatMap(create(settings, client, _))
+      .map(identity)
 
-  def forKey[F[+_]: Sync, A: Decoder](
+  def forKey[F[_]: Sync, A: Decoder](
     settings: JsonSchemaDeserializerSettings,
     client: SchemaRegistryClient
   )(implicit jsonSchema: json.Schema[A], tag: ClassTag[A]): F[KeyDeserializer[F, A]] =
     toJsonSchema[F, A](jsonSchema, settings.jsonSchemaId)
       .flatMap(create(settings, client, _))
+      .map(identity)
 
-  def create[F[+_]: Sync, A: Decoder](
+  def create[F[_]: Sync, A: Decoder](
     settings: JsonSchemaDeserializerSettings,
     client: SchemaRegistryClient,
     schema: JsonSchema

src/test/scala/io/kaizensolutions/jsonschema/JsonSchemaSerDesSpec.scala

@@ -1,14 +1,14 @@
 package io.kaizensolutions.jsonschema
 
-import cats.effect._
-import cats.syntax.all._
+import cats.effect.*
+import cats.syntax.all.*
 import com.dimafeng.testcontainers.DockerComposeContainer.ComposeFile
 import com.dimafeng.testcontainers.munit.TestContainersForAll
 import com.dimafeng.testcontainers.{DockerComposeContainer, ExposedService}
 import fs2.Stream
-import fs2.kafka._
+import fs2.kafka.*
 import fs2.kafka.vulcan.SchemaRegistryClientSettings
-import io.circe.generic.semiauto._
+import io.circe.generic.semiauto.*
 import io.circe.{Codec, Decoder, Encoder}
 import io.confluent.kafka.schemaregistry.client.SchemaRegistryClient
 import io.confluent.kafka.schemaregistry.client.rest.exceptions.RestClientException
@@ -232,7 +232,7 @@ class JsonSchemaSerDesSpec extends CatsEffectSuite with TestContainersForAll {
     assertion(produceElements)
   }
 
-  def consumeFromKafka[F[+_]: Async, A: Decoder: json.Schema: ClassTag](
+  def consumeFromKafka[F[_]: Async, A: Decoder: json.Schema: ClassTag](
     fClient: F[SchemaRegistryClient],
     settings: JsonSchemaDeserializerSettings,
     groupId: String,