[Vm-dev] FilePlugin argument checking - primitiveFailed vs PrimErrBadArgument

[Alistair Grant]

Hi Everyone,

I'm currently extending FilePlugin to allow files to be opened using
either a file descriptor or FILE*.  If you're interested more details
at:

Original PR: https://github.com/pharo-project/pharo-vm/pull/108
Updated PR: https://github.com/pharo-project/pharo-vm/pull/142


While tidying up the argument checking I noticed that FilePlugin has as
part of #primitiveFileOpen:


    namePointer := interpreterProxy stackValue: 1.
    (interpreterProxy isBytes: namePointer)
       ifFalse: [^ interpreterProxy primitiveFail].


My understanding is that this is bad practice as #primitiveFail won't
correctly retry if the argument is a forwarder.  So it should be:


    namePointer := interpreterProxy stackValue: 1.
    (interpreterProxy isBytes: namePointer)
       ifFalse: [^ interpreterProxy primitiveFailFor: PrimErrBadArgument].


Can someone confirm that I'm not misunderstanding, and I'll go through
and check FilePlugin further.


Thanks,
Alistair