Add compiler option sets to ScalaJS target

contrib/scalajs/src/python/pants/contrib/scalajs/targets/scala_js_target.py

@@ -7,7 +7,7 @@
 
 from pants.backend.jvm.subsystems.jvm_platform import JvmPlatform
 from pants.base.payload import Payload
-from pants.base.payload_field import PrimitiveField
+from pants.base.payload_field import PrimitiveField, SetOfPrimitivesField
 
 from pants.contrib.scalajs.subsystems.scala_js_platform import ScalaJSPlatform
 
@@ -24,6 +24,7 @@ def __init__(self, address=None, payload=None, **kwargs):
     payload = payload or Payload()
     payload.add_fields({
       'platform': PrimitiveField(None),
+      'compiler_option_sets': SetOfPrimitivesField(None)
     })
     super(ScalaJSTarget, self).__init__(address=address, payload=payload, **kwargs)
 
@@ -42,6 +43,15 @@ def strict_deps(self):
   def fatal_warnings(self):
     return False
 
+  @property
+  def compiler_option_sets(self):
+    """For every element in this list, enable the corresponding flags on compilation
+    of targets.
+    :return: See constructor.
+    :rtype: list
+    """
+    return self.payload.compiler_option_sets
+
   @property
   def zinc_file_manager(self):
     return False

src/python/pants/backend/jvm/subsystems/zinc_language_mixin.py

@@ -51,7 +51,7 @@ def compiler_option_sets(self):
     :rtype: list
     """
     option_sets = self.get_options().compiler_option_sets
-    if self.get_options().fatal_warnings:
+    if 'fatal_warnings' not in option_sets and self.get_options().fatal_warnings:
       option_sets.append('fatal_warnings')
     return option_sets