proposal: doc: document that Go 1.14 is last to support darwin/arm (32bit version)?

[dmitshur]

iOS 13 (and iPadOS 13) does not support running 32-bit apps. iOS 10 was the last version that supported 32-bit apps (with very visible warnings), and it's 3 years old.

Is it time to remove darwin/arm (leaving just darwin/arm64)? If so, the first step would be to document that Go 1.14 will be the final release with darwin/arm support.

Related to #34749. /cc @bradfitz @hyangah @eliasnaur

[eliasnaur]

Other than the builder, darwin/arm support isn't too much extra hassle than just darwin/arm64.

Go runs on watchOS and tvOS now, and the first darwin/arm64 watch (Watch Series 4) was released just a year ago. Earlier models are 32-bit.

@steeve might care; he had reservations last time I asked. Steeve also runs the hardware darwin/arm builder which has been offline for quite a while.

[bradfitz]

Not having a builder is another good reason to delete it.

That's actually our official policy: https://github.com/golang/go/wiki/PortingPolicy#removing-a-port

[dmitshur]

Thanks for providing that information Elias. I was thinking about watchOS and tvOS but wasn't sure what the state of their 32->64-bit migration was.

From looking over https://en.wikipedia.org/wiki/Apple_TV, I understand the current Apple TV devices (4th and 5th generations) support 64-bit (only?), but 3rd generation (released in 2013, discontinued in 2016) did not.

It sounds like watchOS devices aren't as far along, but iOS/iPadOS and tvOS are.

[steeve]

We are planning on removing arm support in a few weeks/months (most likely when we migrate to xcode 11). Although not just yet.

Supporting older WatchOS hardware looks like a pretty good reason to keep it though since it can now run Go (and I mean, how cool is that), which is fairly new with 1.13.

The builder being off-line is on me though, I'll fix that tomorrow morning.

[eliasnaur]

@dmitshur, I briefly considered AppleTV. Only the 4th generation support the App Store, so we don't need 32-bit support for AppleTV.

[eliasnaur]

Perhaps we should move the discussion to https://golang.org/issue/34847.

[bcmills]

Let's move the builder discussion to #31497, assuming those are still the builders we intend to use.

[bradfitz]

@steeve, you wrote:

We are planning on removing arm support in a few weeks/months (most likely when we migrate to xcode 11). Although not just yet.

Supporting older WatchOS hardware looks like a pretty good reason to keep it though since it can now run Go (and I mean, how cool is that), which is fairly new with 1.13.

Is that a yes or no no removing darwin/arm after Go 1.14?

This is all dependent on builders staying up, so is it worth it to you, given that you're the one running the builders nowadays?

[bradfitz]

(ping @steeve; auto-completed messed up your handle earlier)

[steeve]

@bradfitz I'm sort of glad to announce that we no longer ship darwin/arm. That said, I'm happy to keep the builders up if that helps (ie "old" WatchOS support).

Not that I'll able to dig into why the tests fail (as they are now), but if I'm pinged when they go down (because they are fragile), I can have them up in a few days max.

[bradfitz]

How about we hedge a bit and announce that "Go 1.14 is likely the last release to support 32-bit darwin/arm but 64-bit darwin/arm64 support is unaffected" and see if anybody peeps up with concerns?

Then if our builders prove too difficult to keep up we can remove it, but if they're not causing us problems, we could keep it around a bit longer.

Any objections?

[bcmills]

That seems OK to me, with the proviso that I would want to set the bar for “too difficult to keep up” very low.

If we need to make any significant changes for darwin/arm that aren't necessary for — or at least easily derivable from — darwin/arm64 or some other supported arm platform, we should bias toward removing support rather than spending time on maintenance.

[steeve]

I think this is a good idea.

[gopherbot]

Change https://golang.org/cl/203879 mentions this issue: doc/go1.14: document that Go 1.14 is likely last to support darwin/arm