check-ignore: exit --stdin silently on empty string [qa]

[jorgeorpinel]

Extracted from #4323 (comment)

When you use check-ignore in interactive mode, empty strings produce an error and exit. However empty strings are accepted (never match) without --stdin:

λ cat .dvcignore
*

λ dvc check-ignore --stdin
 anything
anything
 # <- just hit Enter
Empty string is not a valid pathspec. Please use . instead if you meant to match all paths.

λ dvc check-ignore -dn ''
::

So I propose that a) empty strings in --stdin interactive mode simply cause the tool to exit back to the shell prompt and/or b) empty strings sent as targets should just be ignored? (exit tool silently)

[jorgeorpinel]

Cc @karajan1001 WDYT?

[jorgeorpinel]

And as an extra (from #4323 (review)), the cannot use both `--details` and `--quiet` error could also be avoided by just having --quiet win i.e. --details could imply have no effect if combined with --quiet.

[karajan1001]

@jorgeorpinel
For empty string error. I just followed what the Git do,

And they didn't mention this in there documents.

So the question is do we need another exiting method besides Ctrl+C. If so, a) plan and mention it in our doc, if not just b) plan.

---

"cannot use both --details and --quiet" I agree.

[jorgeorpinel]

I see. Well, Git has notoriously poor interface and docs, so not a role model on every single detail 🙂

BTW, git check-ignore --stdin doesn't throw an error on Ctrl+C.

do we need another exiting method besides Ctrl+C

I think my suggestion to use Enter makes for an intuitive UI (except if you're used to git check-ignore but I doubt it's a well known command). And yes either way we'll have a small mention of how to exit --stdin interactive mode in docs.

Thanks!

[karajan1001]

I'm sorry, I'm not quite understanding here. Only Enter without other things gives an empty string to the program if we use input() this is what we are doing here.

[jorgeorpinel]

Only Enter without other things gives an empty string to the program

Ohhh good point sorry, I was confused about that. My idea was to end the interactive mode on empty string then. I see you've already done that in #4368, thanks @karajan1001 !