[Bug]: Also handle directory passed to fish

[thunder-coding]

Steps to reproduce

cd $TMPDIR
fish .

Passing any folder/directory to fish results in a infinite loop where fish keeps saying error: Unable to read input file: Is a directory

fish-shell/src/reader.cpp

Line 4227 in 498e5fa

FLOGF(error, _(L"Unable to read input file: %s"), strerror(err));

This is the file where the problem needs to be solved

What should be done when a directory is passed to fish

Fish should set the current directory to the supplied directory passed through command line

Platforms I confirmed the bug on

• Android 11 Termux fish 3.3.1
• Android 7 Termux fish 3.3.1

[faho]

Running fish . means to tell fish to read . as a script file - this runs like fish foo.fish, except instead of foo.fish you've given a directory. That doesn't work, for obvious reasons.

Fish should set the current directory to the supplied directory passed through command line

I disagree. We should simply reject it when a directory is passed as a script file. Otherwise we'd have to introduce another way of running fish - with a file, read the file, with a directory, go to that directory. This is unfamiliar (e.g. bash doesn't do it) and you're, to my knowledge, the first person to try that.

So let's just fix the failure mode.