test-float-parse: test staging

[jieyouxu]

No objection to the change here to unblock things, but it seems a bit unusual that this tool tests the beta std at all. Is there any way to change it to run on in-tree std with the beta and in-tree compilers?

Originally posted by @tgross35 in #141904 (comment)

[tgross35]

Why is this test always such an edge case for everything 😆

In theory we could probably move it to a harness-less integration test in the std crate. IIRC dev dependencies can’t be made optional though so that’s kind of suboptimal for everyone who would want to run other tests without building test-float-parse’s large-ish dependency tree.

[onur-ozkan]

We are not testing test-float-parse on beta std.

[jieyouxu]

In theory we could probably move it to a harness-less integration test in the std crate. IIRC dev dependencies can’t be made optional though so that’s kind of suboptimal for everyone who would want to run other tests without building test-float-parse’s large-ish dependency tree.

Is the intention that test-float-parse does not wish to support being run against beta std (to save the necessary cfg(not(bootstrap)) or cfg(bootstrap) if beta/in-tree std has differences)? I.e. ./x check src/etc/test-float-parse --stage=0 should error or sth, and ./x check --stage=0 should skip src/etc/test-float-parse?

[tgross35]

I don't think there is ever any purpose on running it against the beta std, since if it finds a problem that's not really actionable (hopefully this never happens), it's mostly for validating changes to the algorithms in-tree.

The default should probably be to run it against the fully current source (in-tree library + in-tree compiler). It would be nice to be able to run it against the in-tree library with a downloaded compiler. I'm not really sure how that translates to the new stages 🙂