[luatex] luatex problem with file with umlauts on windows 10

[Philip Taylor]

Trying to understand why Akira-san had written :

>
>         local function is_texlive ()
>              local a = kpse.var_value ('command_line_encoding')
>              if a
>              then
>                    return true
>              else
>                    return false
>              end
>         end

rather than

>         local function is_texlive ()
>              local a = kpse.var_value ('command_line_encoding')
>              return a
>         end

and similarly later on in the code, I tried modifying the source but ended up with diagnostics that I did not understand.  So, to try to make life simpler, I factored out the Lua code into a separate file and tried running it from the command line.  But even using Akira-san's original code (with Reinhard's suggested simplification), I still get unexpected results.  Could a Lua expert possibly explain why OFILE is reporting 'nil' for "grüße.tex", please ?  Both are in the directory from which I am issuing the TeXLua command.

/Philip Taylor
--------
/
         local function is_texlive ()
              local a = kpse.var_value ('command_line_encoding')
              if a
              then
                    return true
              else
                    return false
              end
         end
         local function is_windows()
             if os.type == 'windows' then
                 return true
             end
         end
         function myfilesize (name)
             kpse.set_program_name ("luatex")
             local ofile =  kpse.find_file (name, "tex", true)
             print (" OFILE: ", ofile)
             local file = ofile
             print (" FILE: ", file)
             if is_windows () and is_texlive ()
             then
                local g = chgstrcp.utf8tosyscp (file)
                file = g
             end
             print (" FILE: ", ofile)
             if file
             then
                local size = lfs.attributes (file, "size")
                local isfile= lfs.isfile (file)
                print ("SIZE: ", size)
                print ("isfile ", isfile)
             end
         end

myfilesize ("gruesse")
myfilesize ("grüße")
--[[ myfilesize ("大豊饒諸衆善法") ]]
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