Unable to :sh when vim argument is a process substitution

[Gary Johnson]

I think this is a bug. In a bash shell on a Linux system, execute
this:

$ vim -N -u NONE <(ls)

Then try to start a shell:

:sh

The command immediately returns.

I discovered a work-around, but I don't know if it works generally.
I mention it mainly to give more information to someone who might be
able to fix the underlying problem.

I created a wrapper for bash which I named mybash and put in my home
directory:

#!/bin/bash
exec < /dev/tty
exec /bin/bash "$@"

If I then start vim like this:

$ SHELL=$HOME/mybash vim -N -u NONE <(ls)

and execute

:sh

it _does_ work.

I don't know why vim should even be aware that its argument is the
result of a process substitution. This might even be bug in bash.

All versions of vim that I have tried exhibit the same behavior,
from 8.0.1453 through 8.1.2231. I have tried bash versions
4.1.5(1), 4.3.48(1) and 4.4.19(1).

Regards,
Gary

[Bram Moolenaar]

It looks like bash connects stdin to the file. This also fails:
:!sh
But this works:
:!sh </dev/tty

I would think this is a shell problem.

--
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