runtime: tracking bug for ARM-based macOS and GOOS/GOARCH values

[bradfitz]

The ARM-based Mac rumors of the past couple years continue to heat up (e.g. https://www.theverge.com/2020/3/27/21196611/arm-macbook-desktop-apple-2021-release-date)

Has anybody given any thought to what we're going to do with runtime.GOOS and runtime.GOARCH if/when that happens, so we don't add ambiguity between darwin/arm64 (which currently means iOS only) and darwin/arm64 (which might also mean macOS in the future)?

Changing GOARCH seems out.

Adding GOOS=macos would break any code that switches on those values.

Perhaps some magic behavior like we did for GOOS=android (implies linux build tags) and GOOS=illumos (implies solaris build tags)? But what would still break code that checks runtime.GOOS.

Perhaps keep darwin/arm64 on both iOS and macOS but add some some runtime exported const DarwinOS = {"macos", "ios", ""} that people could switch on when it matters?

If there's new API, might be nice to get that in earlier. But OTOH, don't want to jump the gun if rumors don't pan out.

[rsc]

If darwin/arm64 doesn't work for macos,
then I think we should reclaim it for macos
and move ios over to ios/arm64, much as we have
android as an almost-synonym for Linux on mobile.
(Many fewer GOOS=darwin users on mobile than desktop.)

I've thought about whether we should have GOOS=macos
independently of this issue, but it seems like too much churn
for too little benefit.

Interesting to note that way back when, we could have done
GOOS=osx and we'd be in the same boat of having the wrong
name. Moving to GOOS=macos will only match Apple terminology
until the next OS rename.

[ianlancetaylor]

I think the suggestion here is:

1. add ios as a valid GOOS value
2. let ios imply darwin much as android implies linux

This will potentially break any existing mobile programs that test runtime.GOOS and expect to see darwin. After this change they will see ios.

This suggests that for 1.15 we should

1. add ios as a valid build tag that implies darwin
2. announce in the release notes that we plan to change to GOOS=ios in a future release

[ianlancetaylor]

CC @hyangah

[cherrymui]

I think (but not sure) gomobile sets ios tag, to distinguish iOS emulator on x86 vs. macOS.

[hyangah]

gomobile uses ios tag and also we use the ios tag in crypto/x509 package. gomobile sets GOOS/GOARCH for crosscompile so it needs to use the right value depending on the go version. I don't think that's too difficult. In addition to gomobile, cc/ @eliasnaur <elias.naur@gmail.com> for gio, @hajimehoshi for ebiten users

…

On Fri, May 1, 2020 at 2:38 PM cherrymui ***@***.***> wrote: I think (but not sure) gomobile sets ios tag, to distinguish iOS emulator on x86 vs. macOS. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#38485 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABGESL63JC4FILQFUNGUQH3RPMJJPANCNFSM4MJZNOPQ> .

-- __

[networkimprov]

cc @eliasnaur @hajimehoshi

[dmitshur]

Interesting to note that way back when, we could have done
GOOS=osx and we'd be in the same boat of having the wrong
name. Moving to GOOS=macos will only match Apple terminology
until the next OS rename.

Also interesting is that Apple currently has macOS, iOS, iPadOS, tvOS, and watchOS.

[hajimehoshi]

As far as I know about mobile application developing, there should be no problem to add ios to GOOS :-)