Warn on use of Windows DOS devices in paths

[ChrisDenton]

What it does

If the user uses a bare dos device name such as aux, windows will convert it to \\.\aux (the aux device). This may be surprising. Clippy could warn the user and suggest they explicitly use \\.\aux if that was intended. Using .\aux could also suppress this lint.

The DOS device names are (case insensitive):

• AUX
• CON
• CONIN$
• CONOUT$
• COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, COM², COM³, COM¹
• LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9, LPT², LPT³, LPT¹
• NUL
• PRN

Lint Name

bare_dos_device_name

Category

suspicious

Advantage

Avoids unexpected and surprising path transformations.

Drawbacks

This is platform specific behaviour.

Example

File::open("aux");

Could be written as:

File::open(r"\\.\aux");

Or

File::open("./aux");