Replace Gradle init scripts with a proper Gradle plugin

.github/workflows/ci.yml

@@ -14,15 +14,16 @@ jobs:
         # NOTE(olafurpg) Windows is not enabled because it times out due to reasons I don't understand.
         # os: [windows-latest, ubuntu-latest]
         os: [ubuntu-latest]
-        java: [8, 17]
+        java: [8, 11, 17]
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-java@v3
         with:
           distribution: "temurin"
           cache: "sbt"
           java-version: ${{ matrix.java }}
-      - run: sbt test
+      - name: Main project tests
+        run: sbt test
 
   docker_test:
     runs-on: ${{ matrix.os }}
@@ -49,7 +50,6 @@ jobs:
           docker run -v $PWD:/sources -w /sources sourcegraph/scip-java:latest scip-java index --cwd circe
           file circe/index.scip || (echo "circe SCIP index doesn't exist!"; exit 1) 
 
-
   bazel:
     runs-on: ubuntu-latest
     steps:

.gitignore

@@ -63,3 +63,5 @@ bazel-testlogs
 bazel-lsif-java
 
 VERSION
+
+semanticdb-gradle-plugin/gradle

build.sbt

@@ -14,17 +14,19 @@ lazy val V =
     val coursier = "2.0.8"
     val bsp = "2.0.0-M13"
     val moped = "0.1.11"
-    def scala213 = "2.13.10"
-    def scala212 = "2.12.17"
-    def scala211 = "2.11.12"
-    def scala3 = "3.2.2"
-    def metals = "0.11.11"
-    def scalameta = "4.7.6"
-    def semanticdbKotlinc = "0.3.0"
-    def testcontainers = "0.39.3"
-    def requests = "0.6.5"
-    def minimalMillVersion = "0.10.0"
-    def millScipVersion = "0.3.2"
+    val gradle = "7.0"
+    val scala213 = "2.13.10"
+    val scala212 = "2.12.17"
+    val scala211 = "2.11.12"
+    val scala3 = "3.2.2"
+    val metals = "0.11.11"
+    val scalameta = "4.7.6"
+    val semanticdbKotlinc = "0.3.0"
+    val testcontainers = "0.39.3"
+    val requests = "0.6.5"
+    val minimalMillVersion = "0.10.0"
+    val millScipVersion = "0.3.2"
+    val kotlinGradlePlugin = "1.5.31"
   }
 
 inThisBuild(
@@ -90,6 +92,7 @@ lazy val agent = project
   .settings(
     fatjarPackageSettings,
     javaOnlySettings,
+    javaToolchainVersion := "8",
     moduleName := "semanticdb-agent",
     libraryDependencies ++=
       List(
@@ -104,8 +107,51 @@ lazy val agent = project
         "Premain-Class" -> "com.sourcegraph.semanticdb_javac.SemanticdbAgent"
       )
   )
+lazy val gradlePlugin = project
+  .in(file("semanticdb-gradle-plugin"))
+  .settings(
+    name := "semanticdb-gradle",
+    scalaVersion := V.scala213,
+    buildInfoPackage := "com.sourcegraph.scip_java",
+    publish / skip := true,
+    javaToolchainVersion := "8",
+    scalacOptions ++= Seq("-target:8", "-release", "8"),
+    libraryDependencies ++=
+      List(
+        "dev.gradleplugins" % "gradle-api" % V.gradle % Provided,
+        "dev.gradleplugins" % "gradle-test-kit" % V.gradle % Provided,
+        "org.jetbrains.kotlin" % "kotlin-gradle-plugin" % V.kotlinGradlePlugin %
+          Provided
+      ),
+    buildInfoKeys :=
+      Seq[BuildInfoKey](
+        version,
+        sbtVersion,
+        scalaVersion,
+        "javacModuleOptions" -> javacModuleOptions,
+        "semanticdbScalacVersions" ->
+          com
+            .sourcegraph
+            .sbtsourcegraph
+            .Versions
+            .cachedSemanticdbVersionsByScalaVersion,
+        "sbtSourcegraphVersion" ->
+          com.sourcegraph.sbtsourcegraph.BuildInfo.version,
+        "semanticdbVersion" -> V.scalameta,
+        "semanticdbKotlincVersion" -> V.semanticdbKotlinc,
+        "mtagsVersion" -> V.metals,
+        "scala211" -> V.scala211,
+        "scala212" -> V.scala212,
+        "scala213" -> V.scala213,
+        "scala3" -> V.scala3,
+        "bspVersion" -> V.bsp,
+        "minimalMillVersion" -> V.minimalMillVersion,
+        "millScipVersion" -> V.millScipVersion
+      )
+  )
+  .enablePlugins(BuildInfoPlugin)
 
-lazy val plugin = project
+lazy val javacPlugin = project
   .in(file("semanticdb-javac"))
   .settings(
     fatjarPackageSettings,
@@ -204,13 +250,14 @@ lazy val cli = project
           }
 
           addJar(
-            (plugin / Compile / Keys.`package`).value,
+            (javacPlugin / Compile / Keys.`package`).value,
             "semanticdb-plugin.jar"
           )
           addJar(
             (agent / Compile / Keys.`package`).value,
             "semanticdb-agent.jar"
           )
+          addJar((gradlePlugin / Compile / assembly).value, "gradle-plugin.jar")
 
           IO.copy(outs)
           val props = new Properties()
@@ -333,13 +380,13 @@ lazy val minimizedSettings = List[Def.Setting[_]](
 lazy val minimized = project
   .in(file("tests/minimized/.j11"))
   .settings(minimizedSettings, javaOnlySettings)
-  .dependsOn(agent, plugin)
+  .dependsOn(agent, javacPlugin)
   .disablePlugins(JavaFormatterPlugin)
 
 lazy val minimized8 = project
   .in(file("tests/minimized/.j8"))
   .settings(minimizedSettings, javaToolchainVersion := "8", javaOnlySettings)
-  .dependsOn(agent, plugin)
+  .dependsOn(agent, javacPlugin)
   .disablePlugins(JavaFormatterPlugin)
 
 def javacModuleOptions =
@@ -364,7 +411,7 @@ lazy val minimized17 = project
     javaToolchainVersion := "17",
     javacOptions ++= javacModuleOptions
   )
-  .dependsOn(agent, plugin)
+  .dependsOn(agent, javacPlugin)
   .disablePlugins(JavaFormatterPlugin)
 
 lazy val minimizedScala = project
@@ -397,7 +444,7 @@ lazy val unit = project
       ),
     buildInfoPackage := "tests"
   )
-  .dependsOn(plugin, cli)
+  .dependsOn(javacPlugin, cli)
   .enablePlugins(BuildInfoPlugin)
 
 lazy val buildTools = project
@@ -407,7 +454,7 @@ lazy val buildTools = project
     (Test / javaOptions) ++=
       List(
         s"-javaagent:${(agent / Compile / Keys.`package`).value}",
-        s"-Dsemanticdb.pluginpath=${(plugin / Compile / Keys.`package`).value}",
+        s"-Dsemanticdb.pluginpath=${(javacPlugin / Compile / Keys.`package`).value}",
         s"-Dsemanticdb.sourceroot=${(ThisBuild / baseDirectory).value}",
         s"-Dsemanticdb.targetroot=${(agent / Compile / target).value / "semanticdb-targetroot"}"
       )
@@ -541,3 +588,5 @@ dumpScipJavaVersion := {
 
   IO.write((ThisBuild / baseDirectory).value / "VERSION", versionValue)
 }
+
+ThisBuild / version := sys.env.get("CI").fold("dev")(_ => version.value)

scip-java/src/main/scala/com/sourcegraph/scip_java/Embedded.scala

@@ -14,6 +14,9 @@ object Embedded {
   def semanticdbJar(tmpDir: Path): Path =
     copyFile(tmpDir, "semanticdb-plugin.jar")
 
+  def gradlePluginJar(tmpDir: Path): Path =
+    copyFile(tmpDir, "gradle-plugin.jar")
+
   def agentJar(tmpDir: Path): Path = copyFile(tmpDir, "semanticdb-agent.jar")
   def coursier(tmpDir: Path): Path = {
     val result = copyFile(tmpDir, "scip-java/coursier")