Merge pull request #481 from bjaglin/scala3-local-rules

test/document how local rules can be written against Scala 3

Author: bjaglin

src/sbt-test/sbt-scalafix/local-rules/build.sbt

@@ -0,0 +1,52 @@
+import _root_.scalafix.sbt.{BuildInfo => Versions}
+
+inThisBuild(
+  List(
+    scalafixDependencies := List(
+      // CollectHead
+      "com.github.xuwei-k" %% "scalafix-rules" % "0.6.5"
+    ),
+    resolvers += Resolver.sonatypeRepo("snapshots"),
+    // out of sync with scalafix.sbt.BuildInfo.scala213 on purpose
+    scalaVersion := "2.13.11",
+    Compat.allowUnsafeScalaLibUpgrade := true
+  )
+)
+
+// LocalSyntacticRule
+val rules = project
+  .disablePlugins(ScalafixPlugin)
+  .settings(
+    libraryDependencies +=
+      ("ch.epfl.scala" %% "scalafix-core" % Versions.scalafixVersion)
+        .cross(CrossVersion.for3Use2_13),
+    libraryDependencies += "joda-time" % "joda-time" % "2.10.6"
+  )
+
+val service = project
+  .dependsOn(rules % ScalafixConfig)
+  .settings(
+    // SyntacticRule
+    libraryDependencies +=
+      ("ch.epfl.scala" %% "example-scalafix-rule" % "3.0.0")
+        .cross(CrossVersion.for3Use2_13) % ScalafixConfig
+  )
+
+// SameProjectSyntacticRule
+val sameproject = project
+  .settings(
+    libraryDependencies +=
+      ("ch.epfl.scala" %% "scalafix-core" % Versions.scalafixVersion)
+        .cross(CrossVersion.for3Use2_13) % ScalafixConfig,
+    // Since sbt 1.10.x (https://github.com/sbt/sbt/pull/7480), scala3-library is not automatically added
+    // to non-standard configurations, but is needed by the Scala 3 compiler, so it must be added explicitly
+    // if no dependency brings it implicitly, which is the case here because the only dependency is for3Use2_13.
+    libraryDependencies ++= {
+      if (scalaBinaryVersion.value == "3")
+        Seq(
+          "org.scala-lang" %% "scala3-library" % scalaVersion.value % ScalafixConfig
+        )
+      else
+        Nil
+    }
+  )