cmd/doc: properly set GOPROXY to avoid deprecation checks

This change fixes a bug that was introduced in CL 675155. Instead of
doing the two step download and run with GOPROXY=off, do the run with
GOPROXY=<download cache>:$GOPROXY, so that we use the previously
downloaded version of pkgsite as the latest.

Fixes #73833

Change-Id: I8803426498ab026602805d6448a130eb11458c99
Reviewed-on: https://go-review.googlesource.com/c/go/+/675576
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Michael Matloob <matloob@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

diff --git a/src/cmd/doc/main.go b/src/cmd/doc/main.go
index ccd851200671691a18089bb6b280a491dbc27a59..490337a0b492d6e115114627bc87fdcada4d2dce 100644 (file)
--- a/src/cmd/doc/main.go
+++ b/src/cmd/doc/main.go
@@ -258,11 +258,22 @@ func doPkgsite(urlPath string) error {
        // exit before exiting ourselves.
        signal.Ignore(signalsToIgnore...)
 
+       // Prepend the local download cache to GOPROXY to get around deprecation checks.
+       env := os.Environ()
+       vars, err := runCmd(nil, "go", "env", "GOPROXY", "GOMODCACHE")
+       fields := strings.Fields(vars)
+       if err == nil && len(fields) == 2 {
+               goproxy, gomodcache := fields[0], fields[1]
+               goproxy = "file://" + filepath.Join(gomodcache, "cache", "download") + "," + goproxy
+               env = append(env, "GOPROXY="+goproxy)
+       }
+
        const version = "v0.0.0-20250520201116-40659211760d"
        cmd := exec.Command("go", "run", "golang.org/x/pkgsite/cmd/internal/doc@"+version,
                "-gorepo", buildCtx.GOROOT,
                "-http", addr,
                "-open", path)
+       cmd.Env = env
        cmd.Stdout = os.Stderr
        cmd.Stderr = os.Stderr