correct tests, repair snapshot in debug mode

ext/mini_racer_extension/mini_racer_extension.cc

@@ -562,7 +562,7 @@ static VALUE rb_snapshot_load(VALUE self, VALUE str) {
     return Qnil;
 }
 
-static VALUE rb_snapshot_warmup(VALUE self, VALUE str) {
+static VALUE rb_snapshot_warmup_unsafe(VALUE self, VALUE str) {
     SnapshotInfo* snapshot_info;
     Data_Get_Struct(self, SnapshotInfo, snapshot_info);
 
@@ -1275,6 +1275,8 @@ rb_context_call_unsafe(int argc, VALUE *argv, VALUE self) {
         call_argv = argv + 1;
     }
 
+    bool missingFunction = false;
+
     {
         Locker lock(isolate);
         Isolate::Scope isolate_scope(isolate);
@@ -1289,7 +1291,7 @@ rb_context_call_unsafe(int argc, VALUE *argv, VALUE self) {
 	MaybeLocal<v8::Value> val = context->Global()->Get(fname);
 
 	if (val.IsEmpty() || !val.ToLocalChecked()->IsFunction()) {
-	    return Qnil;
+	    missingFunction = true;
 	} else {
 
 	    Local<v8::Function> fun = Local<v8::Function>::Cast(val.ToLocalChecked());
@@ -1312,6 +1314,10 @@ rb_context_call_unsafe(int argc, VALUE *argv, VALUE self) {
 	}
     }
 
+    if (missingFunction) {
+	rb_raise(rb_eScriptRuntimeError, "Unknown JavaScript method invoked");
+    }
+
     return convert_result_to_ruby(self, call.result);
 }
 
@@ -1371,7 +1377,7 @@ extern "C" {
 	rb_define_alloc_func(rb_cExternalFunction, allocate_external_function);
 
 	rb_define_method(rb_cSnapshot, "size", (VALUE(*)(...))&rb_snapshot_size, 0);
-	rb_define_method(rb_cSnapshot, "warmup!", (VALUE(*)(...))&rb_snapshot_warmup, 1);
+	rb_define_method(rb_cSnapshot, "warmup_unsafe!", (VALUE(*)(...))&rb_snapshot_warmup_unsafe, 1);
 	rb_define_private_method(rb_cSnapshot, "load", (VALUE(*)(...))&rb_snapshot_load, 1);
 
 	rb_define_method(rb_cIsolate, "idle_notification", (VALUE(*)(...))&rb_isolate_idle_notification, 1);

lib/mini_racer.rb

@@ -212,11 +212,13 @@ module MiniRacer
       wrapped = lambda do |*args|
         begin
 
+          r = nil
+
           begin
             @callback_mutex.synchronize{
               @callback_running = true
             }
-            callback.call(*args)
+            r = callback.call(*args)
           ensure
             @callback_mutex.synchronize{
               @callback_running = false
@@ -232,6 +234,8 @@ module MiniRacer
             end
           }
 
+          r
+
         ensure
           @callback_mutex.synchronize {
             @thread_raise_called = false
@@ -311,8 +315,33 @@ module MiniRacer
   # `size` and `warmup!` public methods are defined in the C class
   class Snapshot
     def initialize(str = '')
+      # ensure it first can load
+      begin
+        ctx = MiniRacer::Context.new
+        ctx.eval(str)
+      rescue MiniRacer::RuntimeError => e
+        raise MiniRacer::SnapshotError.new,  e.message
+      end
+
+      @source = str
+
       # defined in the C class
       load(str)
     end
+
+    def warmup!(src)
+      # we have to do something here
+      # we are bloating memory a bit but it is more correct
+      # than hitting an exception when attempty to compile invalid source
+      begin
+        ctx = MiniRacer::Context.new
+        ctx.eval(@source)
+        ctx.eval(src)
+      rescue MiniRacer::RuntimeError => e
+        raise MiniRacer::SnapshotError.new,  e.message
+      end
+
+      warmup_unsafe!(src)
+    end
   end
 end