Pass javac options to Kapt javacArguments so the javac_options warn='off' option works for annotation processors that print warnings

Author: cheister

src/main/kotlin/io/bazel/kotlin/builder/tasks/KotlinBuilder.kt

@@ -52,6 +52,7 @@ class KotlinBuilder @Inject internal constructor(
     enum class KotlinBuilderFlags(override val flag: String) : Flag {
       TARGET_LABEL("--target_label"),
       CLASSPATH("--classpath"),
+      JAVAC_OPTS("--javacopts"),
       DIRECT_DEPENDENCIES("--direct_dependencies"),
       DEPS_ARTIFACTS("--deps_artifacts"),
       SOURCES("--sources"),
@@ -306,6 +307,8 @@ class KotlinBuilder @Inject internal constructor(
           ?.also {
             addAllSourceJars(it)
           }
+
+        addAllJavacFlags(argMap.optional(KotlinBuilderFlags.JAVAC_OPTS) ?: emptyList())
       }
 
       with(root.infoBuilder) {

src/main/kotlin/io/bazel/kotlin/builder/tasks/jvm/CompilationTask.kt

@@ -111,6 +111,35 @@ internal fun JvmCompilationTask.preProcessingSteps(
   return context.execute("expand sources") { expandWithSourceJarSources() }
 }
 
+internal fun parseJavacArgsToMap(args: List<String>): Map<String, String> {
+  val optionsMap = mutableMapOf<String, String>()
+  var i = 0
+
+  while (i < args.size) {
+    val arg = args[i]
+
+    // map option arguments as key value pairs e.g. --source 8 => ("--source", "8")
+    // map flag arguments as key with value = "true" e.g. map -nowarn => ("-nowarn", "true")
+    if (arg.startsWith("-")) {
+      val hasNext = i + 1 < args.size
+      val nextArg = if (hasNext) args[i + 1] else null
+
+      if (hasNext && !nextArg!!.startsWith("-")) {
+        optionsMap[arg] = nextArg
+        i += 2
+      } else {
+        optionsMap[arg] = "true"
+        i++
+      }
+    } else {
+      // Ignore non-option arguments
+      i++
+    }
+  }
+
+  return optionsMap
+}
+
 internal fun encodeMap(options: Map<String, String>): String {
   val os = ByteArrayOutputStream()
   val oos = ObjectOutputStream(os)
@@ -131,10 +160,11 @@ internal fun JvmCompilationTask.kaptArgs(
   plugins: InternalCompilerPlugins,
   aptMode: String,
 ): CompilationArgs {
-  val javacArgs = mapOf<String, String>(
-    "-target" to info.toolchainInfo.jvm.jvmTarget,
-    "-source" to info.toolchainInfo.jvm.jvmTarget,
-  )
+  val javacArgs = parseJavacArgsToMap(listOf(
+    "-target", info.toolchainInfo.jvm.jvmTarget,
+    "-source", info.toolchainInfo.jvm.jvmTarget,
+  ).plus(inputs.javacFlagsList))
+
   return CompilationArgs().apply {
     xFlag("plugin", plugins.kapt.jarPath)
 

src/main/starlark/core/options/opts.javac.bzl

@@ -24,7 +24,7 @@ _JOPTS = {
         ),
         type = attr.string,
         value_to_flag = {
-            "off": ["-nowarn"],
+            "off": ["-nowarn", "-Xlint:none"],
             "error": ["-Werror"],
             "report": None,
         },