remove scala 2.12 support (#1986)

* remove scala 2.12 support

* move around some source because we don't need as many source dirs

* move more files

* remove annotations

* remove annotations

* Create remove-scala-2.12-support.excludes

* remove some scala-2.12 refs

* remove compat.PartialFunction

* Update remove-scala-2.12-support.excludes

Author: pjfanning

.github/workflows/dependency-graph.yml

@@ -39,4 +39,4 @@ jobs:
       - uses: scalacenter/sbt-dependency-submission@64084844d2b0a9b6c3765f33acde2fbe3f5ae7d3 # v3.1.0
         with:
           configs-ignore: provided optional test TestJdk9 compile-internal runtime-internal pr-validation multi-jvm scala-tool scala-doc-tool
-          modules-ignore: pekko-bench-jmh_2.12 pekko-docs_2.12 pekko-bench-jmh_2.13 pekko-docs_2.13 pekko-bench-jmh_3 pekko-docs_3
+          modules-ignore: pekko-bench-jmh_2.13 pekko-docs_2.13 pekko-bench-jmh_3 pekko-docs_3

.github/workflows/nightly-builds.yml

@@ -114,7 +114,7 @@ jobs:
         # No need to specify the full Scala version. Only the Scala
         # binary version is required and Pekko build will set the right
         # full version from it.
-        scalaVersion: ["2.12.x", "2.13.x", "3.3.x"]
+        scalaVersion: ["2.13.x", "3.3.x"]
         javaVersion: [17, 21]
     env:
       DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}

CONTRIBUTING.md

@@ -236,7 +236,7 @@ Pekko uses [MiMa](https://github.com/lightbend/mima) to validate the binary comp
 PR fails due to binary compatibility issues, you may see an error like this:
 
 ```
-[info] stream: found 1 potential binary incompatibilities while checking against org.apache.pekko:pekko-stream_2.12:2.4.2  (filtered 222)
+[info] stream: found 1 potential binary incompatibilities while checking against org.apache.pekko:pekko-stream_2.13:2.4.2  (filtered 222)
 [error]  * method foldAsync(java.lang.Object,scala.Function2)org.apache.pekko.stream.scaladsl.FlowOps in trait org.apache.pekko.stream.scaladsl.FlowOps is present only in current version
 [error]    filter with: ProblemFilters.exclude[ReversedMissingMethodProblem]("org.apache.pekko.stream.scaladsl.FlowOps.foldAsync")
 ```

LICENSE

@@ -212,7 +212,7 @@ Copyright (c) 2003-2011, LAMP/EPFL
 
 pekko-actor contains code from scala-collection-compat in the `org.apache.pekko.util.ccompat` package
 which has released under an Apache 2.0 license.
-- actor/src/main/scala-2.12/org/apache/pekko/util/ccompat/package.scala
+- actor/src/main/scala/org/apache/pekko/util/ccompat/package.scala
 
 Scala (https://www.scala-lang.org)
 
@@ -222,7 +222,6 @@ Copyright EPFL and Lightbend, Inc.
 
 pekko-actor contains code from scala-library in the `org.apache.pekko.util.ccompat` package
 and in `org.apache.pekko.util.Helpers.scala` which was released under an Apache 2.0 license.
-- actor/src/main/scala-2.12/org/apache/pekko/util/ccompat/package.scala
 - actor/src/main/scala/org/apache/pekko/util/Helpers.scala
 
 Scala (https://www.scala-lang.org)

actor-tests/src/test/scala/org/apache/pekko/dispatch/SameThreadExecutionContextSpec.scala

@@ -29,12 +29,8 @@ class SameThreadExecutionContextSpec extends PekkoSpec with Matchers {
 
     "return a Scala specific version" in {
       val ec = SameThreadExecutionContext()
-      if (util.Properties.versionNumberString.startsWith("2.12")) {
-        ec.getClass.getName should startWith("org.apache.pekko.dispatch.internal.SameThreadExecutionContext")
-      } else {
-        // in 2.13 and higher parasitic is available
-        ec.getClass.getName should ===("scala.concurrent.ExecutionContext$parasitic$")
-      }
+      // in Scala 2.13 and higher parasitic is available
+      ec.getClass.getName should ===("scala.concurrent.ExecutionContext$parasitic$")
     }
 
     "should run follow up future operations in the same dispatcher" in {

actor-tests/src/test/scala-2.13+/org/apache/pekko/util/ByteStringBuilderScala213PlusSpec.scala renamed to actor-tests/src/test/scala/org/apache/pekko/util/ByteStringBuilderScala213PlusSpec.scala

@@ -18,7 +18,6 @@
 package org.apache.pekko.util
 
 import org.apache.pekko
-import pekko.util.ccompat._
 import pekko.util.OptionConverters._
 
 import java.util._
@@ -32,7 +31,6 @@ import scala.annotation.nowarn
  * Remove this once Scala 2.12 support is dropped since all methods are in Scala 2.13+ stdlib
  */
 
-@ccompatUsedUntil213
 @nowarn("msg=deprecated")
 object Scala212CompatTest {
 

actor-tests/src/test/scala/org/apache/pekko/util/Scala212CompatTest.scala

@@ -0,0 +1,21 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# Remove deprecated method in Scheduler
+ProblemFilters.exclude[MissingClassProblem]("org.apache.pekko.compat.PartialFunction")
+ProblemFilters.exclude[MissingClassProblem]("org.apache.pekko.compat.PartialFunction$")
+ProblemFilters.exclude[MissingClassProblem]("org.apache.pekko.util.ccompat.ccompatUsedUntil213")