Fix build with older installed golang versions

[lkolbly]

I tried building cog on my Linux machine (with make cog), and it failed unless I did these things.

Because of https://stackoverflow.com/questions/78519711/toolchain-not-available-error-prevents-me-from-using-any-go-commands and also because it seems like part of the build step needs some wheels built?

[markphelps]

undo this please

[lkolbly]

Ah, no can do mi amigo:

(base) lkolbly@B0K3C14:~/cog$ make cog
... lots of stuff ...
go: downloading go1.25 (linux/amd64)
go: download go1.25 for linux/amd64: toolchain not available
make: *** [Makefile:77: generate] Error 1
(base) lkolbly@B0K3C14:~/cog$ 

[michaeldwan]

@lkolbly how is go installed? what version? this should "just work" since we perform builds and tests in CI on linux

[lkolbly]

@michaeldwan I have 1.22.3:

(base) lkolbly@B0K3C14:~$ go version
go version go1.22.3 linux/amd64

Installed presumably by following the instructions at go.dev (which is to... manually unpack a tarball? Hmm someone should invent a tool to do that for us :D)

Okay so I'm reading https://go.dev/doc/toolchain#config, and it says that:

If the toolchain line is omitted, the module or workspace is considered to have an implicit toolchain goV line, where V is the Go version from the go line. ... For example, a go.mod that says go 1.21.0 with no toolchain line is interpreted as if it had a toolchain go1.21.0 line.

This is a go.mod with no toolchain line, so I guess presumably the toolchain would default to go1.25?

...but, go1.25 is not a valid toolchain, which is the error I'm seeing:

For example, go1.21rc1 and go1.21.0 are toolchain names; go1.21 and go1.22 are not (the initial releases are go1.21.0 and go1.22.0)

So my reading is that, if you don't have a toolchain file, it's invalid to not specify the full patch version for the language? It's weird that go wouldn't lint that though.

(of course, if you have a higher toolchain installed, then go will just use that - in CI presumably you have at least 1.25 installed, so it doesn't try to install 1.25)

But, I think also, this means that I should set the patch version to 1.25.0 (because otherwise it changes the toolchain (and language?) for people with versions 1.25.0 through 1.25.5), I've updated the PR with this change.

(specifying 1.25.0 does exclude all the RCs, I think, where 1.25 maybe does not. Don't quote me on that)

[michaeldwan]

@lkolbly you're right. the directive should include the release: go 1.25.3. There was a time between go 1.21 and 1.23 where the language version and toolchain versions changed, and we've been blind to the issue by using much newer go versions. Your fix it good and we should add it!

Not sure about the makefile change. @tempusfrangit is streamlining the wheel build and removing all the old sdks and runtimes. This might not be needed anymore if you rebase on main.

[lkolbly]

@michaeldwan It's possible that maybe this line is good as-is, but we need a toolchain directive.

But for now, I just updated the PR to 1.25.3 and removed the Makefile change.