RHINO USAGE WARNING: Missed Context.javaToJS() - new reason

[Pippoflash]

Hi,
after long fighting with thousands of:

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Rhino runtime detected object it.gotoandplay.smartfoxserver.data.User of class it.gotoandplay.smartfoxserver.data.User where it expected String, Number, Boolean or Scriptable instance. Please check your code for missing Context.javaToJS() call.

I have noticed another reason:

if (user) - triggers it

if (Boolean(user)) - triggers it

trace("User: " + Boolean(user)) - triggers it

if (user != null) - doesn't trigger it

trace("User: " + (user != null)) - doesn't trigger it

Been looking for this for a long time. Hope it can help.

[rjgtav]

Hi, Thanks for noticing it.
Does this happen every time you run that code or only under some considerable server load?

[Pippoflash]

Every time,
on local machine with just 2 users connected.
It is consistent here (sfs 1.6.9)
It still happens probably somewhere elsein production, can't reproduce locally. I'll add more info when I get them.

[Lapo]

Yes, that's an elusive error from the Rhino JS engine.
In essence you will find that error every time the Rhino engine expects a native JS type but for some reason it is given a Java object.

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if (user) - triggers it

yes, because this should return true/false only for JS native types

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if (Boolean(user)) - triggers it

Again, it expects a native true/false, while you are passing a java Object

trace("User: " + Boolean(user)) - triggers it

As above, can't convert a Java object to a native Bool

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if (user != null) - doesn't trigger it

This one is the correct form to check if any object (JS and Java) is null

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trace("User: " + (user != null)) - doesn't trigger it

Same as above.

Other examples that would trigger it could be

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myNumber = myNumber + User

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myString = myString + User

Another very common example is when a certain variable is holding a roomID (number) instead of a Room (Java Object), that's a common cause of confusion.