CLI design

[aanand]

High-level thoughts, based on a quick skim over gofmt, pep8/flake8/autopep8, eslint and a few language interpreters:

• gofmt fixes by default and prints to stdout. It has a -w option to fix in place, and a -d option to print a diff instead of the fixed output.
• eslintcomplains by default and fixes with --fix.
• pep8 and flake8 have no fixing functionality; autopep8 seems to be the canonical fixer. Not much help.

I'm leaning towards fixing as the default behaviour and checking as a flag (ruby and node have -c|--check).

Additionally, I think checking should by default print nothing to stdout.

Should we accept directories as arguments and recursively scan them for *.{yml,yaml} files? Every linter mentioned above does, so I think the answer is yes.

[marksutherland]

yapf may also be worth a look, it's a python autoformatter in the vein of gofmt.

[marksutherland]

+1 on recursively scanning directories btw, while you can do this with find it seems like it would be a common use case.

[aanand]

yapf looks cool - we should run it on our own code.

[tef]

I'm leaning towards fixing as the default behaviour and checking as a flag (ruby and node have -c|--check).

I think it should be called fixyaml then, not safeyaml :-)

The problem with 'fix by default' is that we're not doing something unambiguous, and it could easily screw up your files

Additionally, I think checking should by default print nothing to stdout.

OTOH: this seems good, and we can add a --foo option or something to echo it

[aanand]

The problem with 'fix by default' is that we're not doing something unambiguous, and it could easily screw up your files

This is fair - gofmt can guarantee that, if you've written valid Go, it'll output valid Go that conforms to its style rules. We can't make the same guarantee, because too much stuff is too difficult to repair.

Still: I believe there's enough low-hanging fruit to make repairing worth the effort, especially when it comes to text editor/pre-commit integration.

[indirect]

I believe there's enough low-hanging fruit to make repairing worth the effort, especially when it comes to text editor/pre-commit integration.

I also very much want this, especially if there’s (eventually) an option that lets my editor highlight my broken lines right away.

[tef]

I believe there's enough low-hanging fruit to make repairing worth the effort

The fixes we've done so far are semantically meaningful though. The easiest changes to make safely automatically are ones of whitespace and formatting, removing comments, etc.

There are some things we could fix automatically that are semantic, quoting barewords. However, unless we work on the full yaml spec as input, we can't guarantee that these barewords would parse the same as strings.

The only safe option is --force-commas so far. Even --force-strings means that on: off becomes "on": "off".

--fix-nodent could be turned on b default, but that's the same as changing the safe yaml spec to allow lists to be indented to same level as containing map.

Which is my other problem with 'fix by default', it effectively changes safeyaml to mean 'safeyaml +whatever we can correct' and that latter part needs to be interactive, or user driven.