julia . does not fail

[jakobnissen]

If a directory is passed as the script to julia, no error is raised, but nothing happens. Possibly a consequence of #36605.
Ideally, this should throw an error.

Example:

$ julia .
$

More insidious example

$ julia --startup=no --project . my_script arg1 arg2 arg3
$

[fredrikekre]

The program (.) is empty

julia> read(pwd())
UInt8[]

See e.g. #36605.

[KristofferC]

I think this can be closed as a dup since this is just a "downstream" effect of #36605

[jakobnissen]

I disagree - currently, #36605 is not yet solved because checking whether a file is a directory is an expensive operation. So, that issue may be closed because it's deemed that the check is not worth it.
If it does, then this issue should still be addressed with a isdir check, since the overhead of checking whether a file is a directory is insignificant compared to starting Julia.
At least let's keep this open until we are 100% sure that the other issue will be fixed, even if a fix comes at the expense of opening files being slower.

[vtjnash]

We could either make this an explicit check when loading source code, or we could try measuring performance of using faccessat to check for the ENOTDIR error as a quick isdir check when opening any file

#36605 (comment)