fix-679: empty lockfiles with no dependencies

[ghost]

Summary

No lockfile is written with empty dependencies, which causes check to fail. Act the same with manifest & lockfile, so write an empty file as-well when no dependencies are going to be installed dependencies: {}.

This will solve: #679

Test plan

$ yarn init
$ yarn install
$ yarn check
$ yarn check --integrity
$ npm run test

[bestander]

How about a unit test?

[ghost]

Yes, I was going to, but it was super late already, added it now. I'm sorry, should have made that clear.

[bestander]

Hey @verth, thanks for adding a test case.
I am currently working on a fix that would refactor this inSync section and we won't need writeEmpty flag case.
However it would be great to add your test anyway, could you rebase your PR after the other one is merged?
I'll add a link here in an hour

[bestander]

#1712

[ghost]

Cool, cool! Will keep my eye on it

[bestander]

Ping #1712 is merged

[ghost]

I tried to kill the commits and merge master with the test only but it was not passing. When testing install manually without dependencies it also did not write the lockfile for me (with v.0.18.0 last commit 15d0112).

Would you know something more by any chance, intentional? (not pushed yet to keep fix alive atm)

outdated

[bestander]

@verth, I don't think we had intentional behavior around edge cases with no dependencies.
I think integrity check should pass for empty lockfile, so go ahead rebase and give it another try if you want

[bestander]

rebase needed

[ghost]

@bestander, rebased and dropped the "code fix" in PR to rely on isSync fix, seems like something small might still be a little off? Since rebase test it not passing, tested it manually as-well and it seemed the yarn.lock was not created.

[bestander]

@verth, currently yarn does not write lockfile if there are no dependencies.
A change in install.js is needed

[ghost]

@bestander Reimplemented a fix now as-well.

My bad this was dragged out so long, thought you only wanted to keep the test in this PR, I probably misinterpreted "currently working on a fix [...] However it would be great to add your test anyway".