Support User: User data defaults to false instead of undefined

[jordwest]

This is a fix for support user, currently broken.

This change sets the user data to false when the session is a support user session, rather than leaving it as undefined which caused an error in the community translator jumpstart.

This change also adds a condition to exit the community translator jumpstart if no user is found, preventing the exception which could halt the boot process.

Support user starts Calypso with no user, which currently causes the communityTranslatorJumpstart function to fail with an exception Cannot read property 'localeSlug' of undefined - see #3843.

Any code that used this function (usually indirectly via translate) was breaking on the exception.

PR #6645 introduced a notices middleware which indirectly called the translator jumpstart somewhere in the Calypso boot process, before the support user was loaded. The localeSlug error thus broke the Calypso boot process.

Closes #3843

Test live: https://calypso.live/?branch=fix/support-user/localeslug-error

cc @deBhal @rralian @yoavf @dllh

[deBhal]

The change looks harmless and has a nice defensive flavour, and I'm quite happy for this to go in, but it's a weird error.

currentUser should be false until we've got a valid user. It gets set in User.initialize() here https://github.com/Automattic/wp-calypso/blob/4105161c2978c28aaac7bfe77658481ae21a7cf7/client/lib/user/user.js or on line 75 just below it.

false.localeSlug evaluates to undefined, which is also falsey, so || ! false.localeSlug should cause this to bail out until the user is loaded (wat).

The only way to get Cannot read property 'localeSlug' of undefined is if User.data is being set to undefined, which it shouldn't be - fetch() might set it to an empty object, and clear() will set it to an empty array oddly enough, but it shouldn't ever be undefined. I'd check that the support user code isn't doing something odd here.

[jordwest]

Ahh! Good catch @deBhal. While other paths were setting the user data to false, support user was exiting early and leaving the user data undefined. Fixed in e19d213.

The change in translator-jumpstart is no longer necessary - do you think it's worth keeping anyway?

[deBhal]

I think leave it in. It won't make any logical difference, but it reads a bit more naturally.

🚢