lint:beautysh pre-commit hook

[casperdcl]

• whitespace formatting (fixes add shfmt hooks to format shell scripts #2834 automate formatting)
• consistent use of print_error()/echo/echo -e/echo >&2
• possibly abstract common functionality into one place
• add pre-commit hook
  • ensure CI tests work
• discuss & document go>=1.13 requirement use python formatter!
• fixes tidy scripts #2969

if reviewing online, make sure to ignore whitespace to see actual changes quicker

[efiop]

consistent use of print_error()/echo/echo -e/echo >&2

possibly abstract common functionality into one place

Let's not bother with those for now, they have a very low priority.

[casperdcl]

Oh also just found https://github.com/lovesegfault/beautysh which is python (yay) but does say

in tests with large Linux system Bash scripts, its error-free score was ~99%

which sounds scary. It's ambiguous whether it means it'll break scripts, or just break formatting.

[casperdcl]

which sounds scary. It's ambiguous whether it means it'll break scripts, or just break formatting.

Got confused with one script:

[[ condition1 && \
   condition2 ]]

where it fixed indentation in such a way that it kept complaining about its own formatting.

I manually fixed this in a way that shouldn't be a problem.

[efiop]

@casperdcl That is pretty scary. Would rather not rely on something so unreliable, as it might cause big problems for an unsuspecting contributor.

[casperdcl]

well idk... it didn't break anything and also is used in https://github.com/Glavin001/atom-beautify. Seems like it'll solve a lot more problems than it may introduce. I know it hasn't broken anything so far because the diff between shfmt and beautysh is 4e87bf9. I don't like shfmt's go dependency any more than @shcheklein :)

[efiop]

@casperdcl To be honest, still quite worried about it, but I am willing to give it a try for now. If anything goes wrong - we'll just get rid of it. Thanks!