Vim adding junk to scripts

Question

Information

VIM version

VIM - Vi IMproved 8.1 (2018 May 18, compiled Feb 29 2020 00:47:39)
macOS version
Included patches: 1-503, 505-680, 682-2292

Operating System: Catalina 10.15.4

What went wrong

I'm sure this will just be a configuration thing but I've been banging my head against the desk for hours trying to figure this out.

EDIT: Below I first noticed this happening on ALEFix - however I've realised even when I do :grep, asofsdfas is logged to the console... I'm going to keep digging.

If anyone knows a way to see what is being executed by vim that would be useful (ie show commands being run? - q: doesn't reveal anything)

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When I run ALEFix on a python file it automatically inserts junk at the top:

asofsdfas
import logging

For me its always the same junk asofsdfas but if I keep saving it keeps inserting it.

Here is my ftplugin/python.vim

" Check Python files with flake8 and pylint.
let b:ale_linters = ['flake8', 'mypy']
" Fix Python files with autopep8 and yapf.
let b:ale_fixers = ['autopep8', 'yapf']

" python syntax
let g:python_highlight_all = 1

If I change to let b:ale_fixers = [] it doesn't occur

If I pip uninstall autopep8 and yapf it doesn't occur

It still occurs if I have either only let b:ale_fixers = ['autopep8'] or let b:ale_fixers = ['yapf']

Please someone help I'm losing my mind

EDIT: Turns out it's also happening on my javascript fixers so isn't specific to this python stuff (but the same behaviour is occurring re: if I change the ale_fixers value)

Answer 1

My problem here was that I had

set shellcmdflag=-ic

in my vimrc

Removing this solved the issue.

I'm still not entirely sure why

EDIT: Oh my lord I've found it and it's colossally stupid. Thanks to @filbrandon:

When you pass the shell a -i, it will read and execute your initialization file (such as .bashrc for bash.) If you're producing any output from that initialization file, that might explain it. If you run bash -ic 'echo hello' do you actually see anything other than "hello"?

Turns out I had echo asofsdfas in my .bashrc.... I'm using a mac so I only was ever checking my .bash_profile.

Thanks for taking this journey with me and apologies and thank you.