[luatex] Why LuaTeX forces extension on reading and writing files?

[Igor Liferenko]

Hi all,

LuaTeX requires extension in file name to work correctly. Consider these tests:

Test for reading (does not work without extension):

    $ echo a > in

    \newread\infile
    \openin\infile=in
    \ifeof\infile
      \message{I am not able to open the file for reading}
    \fi
    \closein\infile
    \bye

Test for writing (adds .tex extension):

    \nopagenumbers
    \newwrite\outfile
    \immediate\openout\outfile=out
    \immediate\write\outfile{a}
    \immediate\closeout\outfile
    \bye

How LuaTeX justifies this odd behavior? Is this just a bug which has
not been fixed or it is intentional?

Extensionless filename is perfectly legitimate - why force an extension?

Best regards,
Igor