What would $GOPACKAGEPATH be set to in your example?

Using a go generate rule to rewrite import paths seems pretty strange. Can you provide more context?

When i fork a gopkg, like github.com/yuin/gopher-lua,
the origin gopkg's base import path is github.com/yuin/gopher-lua.

Some sub package (like gopher-lua/ast) still use github.com/yuin/gopher-lua/ast import path.
I can't build the new fork on new import path(on github.com/chai2010/lua).

I need to use go run fixpath.go -old-path=github.com/yuin/gopher-lua -new-path=github.com/chai2010/lua
to fix the import path.

When use the go generate to invoke the fixpath tool (to current import path),
i hope use $GOPACKAGEPATH instead of the github.com/chai2010/lua.

//go:generate go run cmd/fixpath/fixpath.go -old=... -new=$GOPACKAGEPATH

@robpike

I'm not convinced this is a proper use of go generate, nor that we want to keep throwing in environment variables.

I agree with Russ. Closing.