cmd/go: go get of nested module picks version from outer module

[twmb]

This is a continuation of #56974, which was closed due to being stale and I cannot reopen.

What is the URL of the page with the issue?

https://pkg.go.dev/github.com/twmb/franz-go/pkg/[email protected]

Screenshot

What did you do?

I have a repo, github.com/twmb/franz-go with a module at the top-level repo root and other modules at subdirectories. Whenever I release the repo root (push a tag), I can go get -u the new version of the project within seconds. When I release a sub-module, it takes more time -- and if I release the main module quickly followed by a submodule, it takes tens of minutes (I'm not sure when / if the cache will purge).

Repo structure:

github.com/twmb/franz-go/go.mod
github.com/twmb/franz-go/pkg/kadm/go.mod
...

I've managed tags like this for over a year now, and the wait for submodules has never been this long.

What did you expect to see?

go get github.com/twmb/franz-go/pkg/[email protected] to not fail for 30 minutes.

What did you see instead?

$ go get -u github.com/twmb/franz-go/pkg/[email protected]
go: module github.com/twmb/[email protected] found, but does not contain package github.com/twmb/franz-go/pkg/kadm

for 30 minutes

---

Now, this is happening again -- a separate submodule is also now at 1.6.0 (coincidentally the same as this original issue).

This is happening on v1.20.5.

I released a new module, github.com/twmb/franz-go/pkg/[email protected].

$ go get -x github.com/twmb/franz-go/pkg/[email protected]
go: module github.com/twmb/[email protected] found, but does not contain package github.com/twmb/franz-go/pkg/kmsg

The Go command does not issue any http requests. I suspect it's because I have old franz-go versions in my mod cache:

@m4x3r:~/go/pkg/mod/github.com/twmb
$ ll | grep franz
drwxr-xr-x travisbischel staff 128B Fri Mar 24 11:57:20 2023 franz-go/
dr-xr-xr-x travisbischel staff 480B Fri Mar 24 11:57:20 2023 [email protected]/
dr-xr-xr-x travisbischel staff 480B Sat Mar 25 10:23:19 2023 [email protected]/
dr-xr-xr-x travisbischel staff 480B Thu Apr 13 15:06:39 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Fri Mar 24 12:27:20 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Fri Mar 24 12:27:05 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Fri Apr 14 13:21:41 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Tue May  9 12:35:53 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Tue May 30 11:32:44 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Fri Jun  2 11:47:55 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Wed Jul  5 23:57:52 2023 [email protected]/
dr-xr-xr-x travisbischel staff 480B Mon Apr 10 11:26:22 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Mon Apr  3 21:59:03 2023 [email protected]/
dr-xr-xr-x travisbischel staff 512B Wed Apr  5 10:58:13 2023 [email protected]/

So go sees [email protected] exists, but because kmsg is a separate module, the pkg is not in that top-level module:

@m4x3r:~/go/pkg/mod/github.com/twmb/[email protected]/pkg
$ ll
dr-xr-xr-x travisbischel staff 128B Mon Apr  3 21:59:03 2023 kbin/
dr-xr-xr-x travisbischel staff  96B Mon Apr  3 21:59:03 2023 kerr/
dr-xr-xr-x travisbischel staff 1.1K Mon Apr  3 21:59:03 2023 kgo/
dr-xr-xr-x travisbischel staff 128B Mon Apr  3 21:59:03 2023 kversion/
dr-xr-xr-x travisbischel staff 224B Mon Apr  3 21:59:03 2023 sasl/

I suspect this is causing the failure we see.

[bcmills]

@twmb, does this resolve on its own after some amount of time, or does it remain reproducible until some other change to your module cache occurs?

If it is purely time-based, then I suspect it is related to #38065.

[twmb]

@bcmills it resolved after time -- it took >20 minutes. I'm not sure when exactly things started working. I eventually noticed a problem with v1.6.0 and tagged v1.6.1 -- that also took >20 minutes to pick up, but the output from -x showed that the mod database was 404ing trying to get the tag (so it seemed like the 404 was cached for a long time as well). I eventually went to sleep and the next day, everything was resolved.

[seankhliao]

Sounds like this is probably #38065