• Run examples\fan\demo.fan
• Go to "Text" tab, click "Serialize Demo"
• Set focus in right-hand text box, select all and copy to clipboard.
• Go to "Serialization" tab
• Replace text in left-hand text box with contents of clipboard.
• Click "=>"
• Error message is shown:

  sys::IOErr: Cannot set field fwt::Combo.items: sys::ArgErr: Wrong type for field fwt::Combo.items: sys::Obj[] != sys::Str[] [Line 313]
    fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:280)
    fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:224)
    fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
    fanx.serial.ObjDecoder.readComplexAdd (ObjDecoder.java:248)
    fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:236)
    fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
    fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:268)
    fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:224)
    fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
    fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:268)
    fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:224)
    fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
    fanx.serial.ObjDecoder.readComplexAdd (ObjDecoder.java:248)
    fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:236)
    fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
    fanx.serial.ObjDecoder.readComplexAdd (ObjDecoder.java:248)
    fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:236)
    fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
    fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:268)
    fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:224)
    fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
    More...
  Cause:
    sys::ArgErr: Wrong type for field fwt::Combo.items: sys::Obj[] != sys::Str[]
      fan.sys.Field.set (Field.java:103)
      fan.sys.Field.set (Field.java:79)
      fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:276)
      fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:224)
      fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
      fanx.serial.ObjDecoder.readComplexAdd (ObjDecoder.java:248)
      fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:236)
      fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
      fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:268)
      fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:224)
      fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
      fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:268)
      fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:224)
      fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
      fanx.serial.ObjDecoder.readComplexAdd (ObjDecoder.java:248)
      fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:236)
      fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
      fanx.serial.ObjDecoder.readComplexAdd (ObjDecoder.java:248)
      fanx.serial.ObjDecoder.readComplex (ObjDecoder.java:236)
      fanx.serial.ObjDecoder.readObj (ObjDecoder.java:143)
      fanx.serial.ObjDecoder.readComplexField (ObjDecoder.java:268)
      More...

I guess I am not surprised that something as complex as the entire demo doesn't serialize correct - I've never tried that. But I will take a look when I get a chance. Thanks.

I think this is a bug in Field.java:

// check generic type (the Java runtime will check non-generics)
if (of.isGenericInstance() && value != null)
{
  if (!of.is(type(value)))
    throw ArgErr.make("Wrong type for field " + qname() + ": " + of + " != " + type(value)).val;
}

The code is checking whether the destination field's type fits the new value's type, but it should be checking the other way around.

// check generic type (the Java runtime will check non-generics)
if (of.isGenericInstance() && value != null)
{
  if (!type(value).is(of))
    throw ArgErr.make("Wrong type for field " + qname() + ": " + of + " != " + type(value)).val;
}

The C# sources need to be fixed likewise.

Promoted to ticket #518 and assigned to brian

Renamed from Problem in examples\fan\demo.fan to Problem in check of reflective field set

Thanks for tracking that problem down. Seems we were missing a test for that case. I pushed the fix and added a test.

Ticket resolved in 1.0.42

Verified against tip, thanks for the fix.