find module of dependent package

[Dan Kortschak]

Say I have a package path, "host.org/user/depmodule/pkgdep", which is
the path to a dependency of "host.org/user/repomain/pkgmain". The
go.mod file in host.org/user/repomain will have a line
"host.org/user/depmodule" in the require block. If I want to
programmatically find what the module path is from the package path
"host.org/user/depmodule/pkgdep", how can I do this?

go list -m only works with module paths, so doing `go list -m
host.org/user/depmodule/pkgdep' when I'm in
host.org/user/repomain/pkgmain gives me:

go list -m: module host.org/user/depmodule/pkgdep: not a known dependency

Is there a way I can use go list to get this information, or a helper
function somewhere that does this? (The go tool must have this capacity
since go get depends on it when grabbing dependencies).

thanks
Dan

[Dan Kortschak]

Solved thanks to Daniel Martí; use `go list -json` and grab the Module
struct out of that.