Deal with bad executor early

Author: pitr-ch

lib/concurrent/actor.rb

@@ -65,10 +65,14 @@ def self.root
     # @param args see {.to_spawn_options}
     # @return [Reference] never the actual actor
     def self.spawn(*args, &block)
+      options = to_spawn_options(*args)
+      if options[:executor] && options[:executor].is_a?(ImmediateExecutor)
+        raise ArgumentError, 'ImmediateExecutor is not supported'
+      end
       if Actor.current
-        Core.new(to_spawn_options(*args).merge(parent: Actor.current), &block).reference
+        Core.new(options.merge(parent: Actor.current), &block).reference
       else
-        root.ask([:spawn, to_spawn_options(*args), block]).value!
+        root.ask([:spawn, options, block]).value!
       end
     end
 

lib/concurrent/actor/core.rb

@@ -172,7 +172,6 @@ def ns_initialize(opts, &block)
         allocate_context
 
         @executor = Type! opts.fetch(:executor, @context.default_executor), Concurrent::AbstractExecutorService
-        raise ArgumentError, 'ImmediateExecutor is not supported' if @executor.is_a? ImmediateExecutor
 
         @reference = (Child! opts[:reference_class] || @context.default_reference_class, Reference).new self
         @name      = (Type! opts.fetch(:name), String, Symbol).to_s