Catch macro expansion exceptions in ScalacWorker

src/java/io/bazel/rulesscala/scalac/ScalacWorker.java

@@ -248,6 +248,15 @@ private static String[] getPluginParamsFrom(CompileOptions ops) {
     return pluginParams.toArray(new String[pluginParams.size()]);
   }
 
+  private static boolean isMacroException(Throwable ex) {
+    for (StackTraceElement elem : ex.getStackTrace()) {
+      if (elem.getMethodName().equals("macroExpand")) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   private static void compileScalaSources(CompileOptions ops, String[] scalaSources, Path classes)
       throws IOException {
 
@@ -269,6 +278,8 @@ private static void compileScalaSources(CompileOptions ops, String[] scalaSource
     } catch (Throwable ex) {
       if (ex.toString().contains("scala.reflect.internal.Types$TypeError")) {
         throw new RuntimeException("Build failure with type error", ex);
+      } else if (isMacroException(ex)) {
+        throw new RuntimeException("Build failure during macro expansion", ex);
       } else {
         throw ex;
       }

test/shell/test_persistent_worker.sh

@@ -0,0 +1,33 @@
+# shellcheck source=./test_runner.sh
+
+dir=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+. "${dir}"/test_runner.sh
+. "${dir}"/test_helper.sh
+runner=$(get_test_runner "${1:-local}")
+
+PERSISTENT_WORKER_FLAGS="--strategy=Scalac=worker --worker_sandboxing"
+
+test_persistent_worker_success() {
+  # shellcheck disable=SC2086
+  bazel build //test:ScalaBinary $PERSISTENT_WORKER_FLAGS
+}
+
+test_persistent_worker_failure() {
+  action_should_fail "build //test_expect_failure/diagnostics_reporter:error_file $PERSISTENT_WORKER_FLAGS"
+}
+
+test_persistent_worker_handles_exception_in_macro_invocation() {
+  command="bazel build //test_expect_failure/scalac_exceptions:bad_macro_invocation $PERSISTENT_WORKER_FLAGS"
+  output=$(${command} 2>&1)
+  ! (echo "$output" | grep -q -- "---8<---8<---") && (echo "$output" | grep -q "Build failure during macro expansion")
+
+  RESPONSE_CODE=$?
+  if [ $RESPONSE_CODE -ne 0 ]; then
+    echo -e "${RED} Scalac persistent worker does not handle uncaught error in macro expansion. $NC"
+    exit 1
+  fi
+}
+
+$runner test_persistent_worker_success
+$runner test_persistent_worker_failure
+$runner test_persistent_worker_handles_exception_in_macro_invocation

test_expect_failure/scalac_exceptions/BUILD

@@ -0,0 +1,12 @@
+load("//scala:scala.bzl", "scala_library", "scala_macro_library")
+
+scala_macro_library(
+    name = "bad_macro",
+    srcs = ["BadMacro.scala"],
+)
+
+scala_library(
+    name = "bad_macro_invocation",
+    srcs = ["BadMacroInvocation.scala"],
+    deps = [":bad_macro"],
+)

test_expect_failure/scalac_exceptions/BadMacro.scala

@@ -0,0 +1,9 @@
+import scala.language.experimental.macros
+
+object BadMacro {
+  def badMacro(): Unit = macro badMacroImpl
+
+  def badMacroImpl(c: scala.reflect.macros.blackbox.Context)(): c.Tree = {
+    throw new NoSuchMethodError()
+  }
+}

test_expect_failure/scalac_exceptions/BadMacroInvocation.scala

@@ -0,0 +1,3 @@
+object BadMacroInvocation {
+  BadMacro.badMacro()
+}

test_rules_scala.sh

@@ -55,3 +55,4 @@ $runner bazel build //test_statsfile:SimpleNoStatsFile_statsfile --extra_toolcha
 . "${test_dir}"/test_compiler_dependency_tracking.sh
 . "${test_dir}"/test_twitter_scrooge.sh
 . "${test_dir}"/test_inherited_environment.sh
+. "${test_dir}"/test_persistent_worker.sh