Unability to open generalised "file descriptor" files eg: /proc/self/fd/xxx

Description

Many unices and unix-like OS-es support special directory in /proc (or elsewhere) to open inherited parent's proces file descriptors as files.

This is often used by advanced shell sub process redirection (bash, zsh and other more advanced shells).

Example:

$ nano <(ls) 
# "opens" directory listing as editable buffer (incoming as "descriptor" file from shell, containing actual output of `ls`)

Unfortunately with micro this fails:

: micro <(ls)                 
Error: /proc/self/fd/11 is not a regular file and cannot be opened

Press enter to continue

micro is probably doing regular file check on it's input file argument and raw file descriptor fails this.
This might be some kind of protection.

However this should be at least specialcased for file prefixes like /proc/self/fd/* on linux, to allow for shell sub-process redirection to work.

Environment

• Version:
• OS:
• Terminal:

Start by reproducing the reported command, micro <(ls), and trace the input-file argument handling that rejects /proc/self/fd/11 as not a regular file. Review the existing file-opening checks and make the behavior work for the reported descriptor paths without breaking ordinary path validation; done means process-substitution input opens in micro.