Discontinue the deprecated screaming snake case constants from dart:io

[natebosch]

Forking the conversation from #31813

We have added new lowercase constants and migrated all internal code, and external code authored by the Dart team to use it. We need to determine whether we want to remove the deprecated constants for Dart 3.0 (then figure out how to keep track of these things so we don't miss them for that release)

My vote would be to remove them. They'll be deprecated for a long time by that point and the migration is really easy to do.

[srawlins]

Dart three-point-ohhhhhhh

[natebosch]

@mit-mit - Have we decided on how we will collect and track these decisions? In this case we've discussed even removing them before Dart 3.0

[lrhn]

Proof-of-concept: https://dart-review.googlesource.com/c/sdk/+/219791
(Proving that it's not that simple).

[mit-mit]

Does dart fix already support updating code away from these to their non-screaming equivalents?

[natebosch]

Does dart fix already support updating code away from these to their non-screaming equivalents?

Most of them.

There are a couple that are not covered because dart fix does not have a way to express them yet.
#45393 (comment)

[mit-mit]

@natebosch the issue you linked to looks resolved, so does dart fix support them all now?

[natebosch]

so does dart fix support them all now?

No. https://dart-review.googlesource.com/c/sdk/+/214068 attempts to use these fixes and the test failures show that there is still a problem. I forwarded you an internal thread with some more detail.

[mit-mit]

Updating title: Analysis of both internal and external code shows very little use of these long discontinued SCREAMING CASE APIs, so we're going ahead with the removal.