Remove support for Scala 2 (#150)

* Remove support for Scala 2

* Update nav config

build.sbt

@@ -1,16 +1,8 @@
-// We have two builds of Jelly – both compiled using the Scala 3 compiler, but one with
-// Scala 2.13 dependencies and the other with Scala 3 dependencies. This is because we
-// want to at least somewhat support both Scala 2.13 and Scala 3 projects that use Jelly.
-// The "fake" Scala 2.13 build is published with the _2.13 suffix.
-lazy val scala2Version = "3.3.2" // This is the fake Scala 2 version
-lazy val scala3Version = "3.3.3" // This is the real Scala 3 version
-
 // Scala 2 version used for meta-programming – transforming the generated proto classes.
 // Not used to compile any of the Jelly projects.
 lazy val scala2MetaVersion = "2.13.14"
 
-ThisBuild / scalaVersion := scala3Version
-ThisBuild / crossScalaVersions := Seq(scala2Version, scala3Version)
+ThisBuild / scalaVersion := "3.3.3"
 ThisBuild / organization := "eu.ostrzyciel.jelly"
 ThisBuild / homepage := Some(url("https://w3id.org/jelly/jelly-jvm"))
 ThisBuild / licenses := List("Apache-2.0" -> url("https://www.apache.org/licenses/LICENSE-2.0"))
@@ -38,31 +30,8 @@ lazy val rdf4jV = "5.0.2"
 // When updating also change the version in plugins.sbt
 lazy val scalapbV = "0.11.13"
 
-// Helper function to transform Scala 3 dependencies into Scala 2 ones
-def crossDependencies(binVersion: String, modules: ModuleID*): Seq[ModuleID] = {
-  if (binVersion == scala2Version) {
-    modules.map(_.cross(CrossVersion.for3Use2_13))
-  }
-  else modules
-}
-
-// List of exclusions for the grpc module and its dependencies (when building for Scala 2)
-lazy val grpcExclusions2 = Seq(
-  ExclusionRule(organization = "org.parboiled", name = "parboiled_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-protobuf-v3_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-actor_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-stream_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-http_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-discovery_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-parsing_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-http-cors_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-http-core_3"),
-  ExclusionRule(organization = "org.apache.pekko", name = "pekko-grpc-runtime_3"),
-  ExclusionRule(organization = "com.typesafe", name = "ssl-config-core_3"),
-)
-
-// List of exclusions for the grpc module and its dependencies (when building for Scala 3)
-lazy val grpcExclusions3 = Seq(
+// List of exclusions for the grpc module and its dependencies
+lazy val grpcExclusions = Seq(
   ExclusionRule(organization = "org.scala-lang.modules", name = "scala-collection-compat_2.13"),
   ExclusionRule(organization = "com.thesamet.scalapb", name = "lenses_2.13"),
   ExclusionRule(organization = "com.thesamet.scalapb", name = "scalapb-runtime_2.13"),
@@ -84,31 +53,17 @@ lazy val commonSettings = Seq(
     case x if x.endsWith("io.netty.versions.properties") => MergeStrategy.first
     case x => assemblyMergeStrategy.value(x)
   },
-  excludeDependencies ++= {
-    if (scalaVersion.value == scala2Version) Seq(
-      ExclusionRule(organization = "org.scala-lang.modules", name = "scala-collection-compat_3"),
-      ExclusionRule(organization = "com.thesamet.scalapb", name = "lenses_3"),
-      ExclusionRule(organization = "com.thesamet.scalapb", name = "scalapb-runtime_3"),
-    )
-    else Seq()
-  },
-  crossVersion := {
-    // Publish our fake Scala 2 project with _2.13 suffix
-    if (scalaVersion.value == scala2Version) CrossVersion.Constant("2.13")
-    else CrossVersion.binary
-  },
+  crossVersion := CrossVersion.binary,
 )
 
 // Intermediate project that generates the Scala code from the protobuf files
 lazy val rdfProtos = (project in file("rdf-protos"))
   .settings(
     name := "jelly-scalameta-test",
-    libraryDependencies ++= crossDependencies(scalaVersion.value,
+    libraryDependencies ++= Seq(
       "com.thesamet.scalapb" %% "compilerplugin" % scalapbV,
       "com.thesamet.scalapb" %% "scalapb-runtime" % scalapbV % "protobuf",
       "com.thesamet.scalapb" %% "scalapb-runtime-grpc" % scalapbV,
-    ),
-    libraryDependencies ++= Seq(
       "io.grpc" % "grpc-netty" % scalapb.compiler.Version.grpcJavaVersion,
     ),
     Compile / PB.targets := Seq(
@@ -125,7 +80,7 @@ lazy val core = (project in file("core"))
   .settings(
     name := "jelly-core",
     description := "Core code for serializing and deserializing RDF data in the Jelly format.",
-    libraryDependencies ++= crossDependencies(scalaVersion.value,
+    libraryDependencies ++= Seq(
       "com.thesamet.scalapb" %% "scalapb-runtime" % scalapbV,
     ),
     // Add the generated proto classes after transforming them with Scalameta
@@ -198,7 +153,7 @@ lazy val stream = (project in file("stream"))
   .settings(
     name := "jelly-stream",
     description := "Utilities for using the Jelly RDF serialization format with Reactive Streams (via Apache Pekko).",
-    libraryDependencies ++= crossDependencies(scalaVersion.value,
+    libraryDependencies ++= Seq(
       "org.apache.pekko" %% "pekko-actor-typed" % pekkoV,
       "org.apache.pekko" %% "pekko-stream-typed" % pekkoV,
     ),
@@ -211,7 +166,7 @@ lazy val grpc = (project in file("grpc"))
   .settings(
     name := "jelly-grpc",
     description := "Implementation of a gRPC client and server for the Jelly gRPC streaming protocol.",
-    libraryDependencies ++= crossDependencies(scalaVersion.value,
+    libraryDependencies ++= Seq(
       "com.typesafe.scala-logging" %% "scala-logging" % "3.9.5",
       "org.apache.pekko" %% "pekko-actor-typed" % pekkoV,
       "org.apache.pekko" %% "pekko-discovery" % pekkoV,
@@ -225,10 +180,7 @@ lazy val grpc = (project in file("grpc"))
       (rdfProtos / baseDirectory).value / "src" / "main" / "protobuf",
     ),
     Compile / PB.generate / excludeFilter := "rdf.proto",
-    excludeDependencies ++= {
-      if (scalaVersion.value == scala2Version) grpcExclusions2
-      else grpcExclusions3
-    },
+    excludeDependencies ++= grpcExclusions,
     commonSettings,
   )
   .dependsOn(stream % "test->compile")
@@ -255,10 +207,7 @@ lazy val examples = (project in file("examples"))
       "org.eclipse.rdf4j" % "rdf4j-rio-turtle" % rdf4jV,
       "org.eclipse.rdf4j" % "rdf4j-rio-nquads" % rdf4jV,
     ),
-    excludeDependencies ++= {
-      if (scalaVersion.value == scala2Version) grpcExclusions2
-      else grpcExclusions3
-    },
+    excludeDependencies ++= grpcExclusions,
     commonSettings,
   )
   .dependsOn(grpc, stream, jena, rdf4j)

docs/docs/getting-started-devs.md

@@ -2,11 +2,11 @@
 
 *If you don't want to code anything and only use Jelly with your Apache Jena/RDF4J application, see [the dedicated guide](getting-started-plugins.md) about using Jelly-JVM as a plugin.*
 
-This guide explains a few of the basic functionalities of Jelly-JVM and how to use them in your code. Jelly-JVM is written in Scala, but it can be used from Java as well. However, in this guide, we will focus on **Scala 3**[^1].
+This guide explains a few of the basic functionalities of Jelly-JVM and how to use them in your code. Jelly-JVM is written in Scala, but it can be used from Java as well. However, in this guide, we will focus on **Scala 3**.
 
 ## Quick start – plain old files
 
-Depending on your RDF library of choice (Apache Jena or RDF4J), you should import one of two dependencies: `jelly-jena` or `jelly-rdf4j`[^2]. In our examples we will use Jena, so let's add this to your `build.sbt` file (this would be the same for other build tools like Maven or Gradle):
+Depending on your RDF library of choice (Apache Jena or RDF4J), you should import one of two dependencies: `jelly-jena` or `jelly-rdf4j`[^1]. In our examples we will use Jena, so let's add this to your `build.sbt` file (this would be the same for other build tools like Maven or Gradle):
 
 ```scala title="build.sbt"
 lazy val jellyVersion = "{{ jvm_package_version() }}"
@@ -140,8 +140,7 @@ Jelly is a bit more than just a serialization format – it also defines a [gRPC
 - [RiverBench ci-worker](https://github.com/RiverBench/ci-worker) – a real-world application that is used for processing large RDF datasets in a CI/CD pipeline. It uses Jelly-JVM for serialization and deserialization with Apache Jena. It also uses extensively Apache Pekko Streams.
 
 
-[^1]: Jelly-JVM is written in Scala 3, but we do have Scala 2.13-compatible builds available on Maven Central. [Read more about the details and caveats](user/scala2.md).
-[^2]: There is nothing stopping you from using both at the same time. You can also pretty easily add support for any other Java-based RDF library by implementing a few interfaces. [More details here](dev/implementing.md).
+[^1]: There is nothing stopping you from using both at the same time. You can also pretty easily add support for any other Java-based RDF library by implementing a few interfaces. [More details here](dev/implementing.md).
 
 ## Questions?
 

docs/docs/index.md

@@ -67,7 +67,6 @@ Below is a list of all documentation pages about Jelly-JVM. You can also browse
     - [gRPC](user/grpc.md)
     - [Useful utilities](user/utilities.md)
     - [Compatibility policy](user/compatibility.md)
-    - [Scala 2.13 builds](user/scala2.md)
 - Developer guide
     - [Releases](dev/releases.md)
     - [Implementing Jelly for other libraries](dev/implementing.md)
@@ -78,4 +77,4 @@ Below is a list of all documentation pages about Jelly-JVM. You can also browse
 
 
 
-[^1]: Scala 2.13-compatible builds of Jelly-JVM are available as well. [See more details](user/scala2.md).
+[^1]: Scala 2.13-compatible builds of Jelly-JVM are available for Jelly-JVM 1.0.x. Scala 2 support was removed in subsequent versions. [See more details](https://w3id.org/jelly/jelly-jvm/1.0.x/user/scala2).

docs/docs/user/compatibility.md

@@ -6,7 +6,7 @@ Jelly-JVM follows [Semantic Versioning 2.0.0](https://semver.org/), with MAJOR.M
 
 The current version of Jelly-JVM is compatible with Java 17 and newer. Java 17, 21, and 22 are tested in CI and are guaranteed to work. We recommend using a recent release of [GraalVM](https://www.graalvm.org/) to get the best performance. If you need Java 11 support, you should use [Jelly-JVM 1.0.x](https://w3id.org/jelly/jelly-jvm/1.0.x).
 
-Jelly is built with [Scala 3 LTS releases](https://www.scala-lang.org/blog/2022/08/17/long-term-compatibility-plans.html), however, [Scala 2.13-compatible builds are available as well](scala2.md).
+Jelly is built with [Scala 3 LTS releases](https://www.scala-lang.org/blog/2022/08/17/long-term-compatibility-plans.html) and supports only Scala 3. If you need Scala 2 support, you should use [Jelly-JVM 1.0.x](https://w3id.org/jelly/jelly-jvm/1.0.x).
 
 ## RDF libraries
 
@@ -22,7 +22,6 @@ Auto-generated classes in the `jelly-core` module, `eu.ostrzyciel.jelly.core.pro
 
 ## See also
 
-- [Scala 2.13 builds](scala2.md)
 - [Release notes on GitHub](https://github.com/Jelly-RDF/jelly-jvm/releases)
 - [Making Jelly-JVM releases](../dev/releases.md)
 - [Contributing to Jelly-JVM](../contributing.md)

docs/mkdocs.yml

@@ -96,7 +96,6 @@ nav:
     - Useful utilities: 'user/utilities.md'
     - Low-level usage: 'user/low-level.md'
     - Compatibility policy: 'user/compatibility.md'
-    - Scala 2 builds: 'user/scala2.md'
   - Developer guide:
     - Releases: 'dev/releases.md'
     - Implementing Jelly for other libraries: 'dev/implementing.md'