cmd/go: prevent packages from being cleaned more than once

If a package was listed as a dependency from multiple places, it
could have been cleaned repeatedly.

R=golang-dev, dave, rsc, seed, bradfitz
CC=golang-dev, minux.ma
https://golang.org/cl/7482043

diff --git a/src/cmd/go/clean.go b/src/cmd/go/clean.go
index ba600d3bb1b3249e2de42c1ef84b031934c8fcae..8345c9af15e9c247f90c67d68b932614277b1988 100644 (file)
--- a/src/cmd/go/clean.go
+++ b/src/cmd/go/clean.go
@@ -106,6 +106,8 @@ func clean(p *Package) {
        if cleaned[p] {
                return
        }
+       cleaned[p] = true
+
        if p.Dir == "" {
                errorf("can't load package: %v", p.Error)
                return