CSV.write somehow cannot write file with name `con.csv` in Windows?!

[mzy2240]

MWE:

using DataFrames, CSV

df = DataFrame(:a => [1,2])
CSV.write("C:/Users/zmao/Desktop/test/con.csv", df)

Julia version: 1.9.2 Windows version: Windows 10 Enterprise 22H2

[quinnj]

Can you share the error you're seeing?

[mzy2240]

No error but the generated file does not exist

[mzy2240]

Ok this is the reason: https://stackoverflow.com/questions/59345760/os-path-exists-gives-false-positive-for-files-named-con-csv-on-windows

[mzy2240]

then why there is no error?

[hhaensel]

These names behave like files, i.e. they support open, write and read, but they do different things than you expect, see e.g. https://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx.

There is simply no way to generate a file on Win-Os that with the basename "con". Renaming also doesn't work. If you want to make sure that such name is not used, check beforehand, e.g.

if lowercase(splitext(basename(filename))[1]) == "con"
  @info "Filename '$(uppercase(basename(filename)))' not supported under Windows"
end