cmd/go: add clean -modcache

We need an easy way to remove $GOPATH/src/mod,
especially since all the directories are marked read-only.

Change-Id: Ib9e8e47e50048f55ecc4de0229b06c4a416ac114
Reviewed-on: https://go-review.googlesource.com/124382
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

diff --git a/src/cmd/go/internal/clean/clean.go b/src/cmd/go/internal/clean/clean.go
index fa5af944af6c90f36d5e0792554ca2f551de0840..40cb324ac21003d1ff00f2d10397010bcea99945 100644 (file)
--- a/src/cmd/go/internal/clean/clean.go
+++ b/src/cmd/go/internal/clean/clean.go
@@ -17,11 +17,12 @@ import (
        "cmd/go/internal/cache"
        "cmd/go/internal/cfg"
        "cmd/go/internal/load"
+       "cmd/go/internal/modfetch"
        "cmd/go/internal/work"
 )
 
 var CmdClean = &base.Command{
-       UsageLine: "clean [-i] [-r] [-n] [-x] [-cache] [-testcache] [build flags] [packages]",
+       UsageLine: "clean [clean flags] [build flags] [packages]",
        Short:     "remove object files and cached files",
        Long: `
 Clean removes object files from package source directories.
@@ -65,6 +66,10 @@ The -cache flag causes clean to remove the entire go build cache.
 The -testcache flag causes clean to expire all test results in the
 go build cache.
 
+The -modcache flag causes clean to remove the entire module
+download cache, including unpacked source code of versioned
+dependencies.
+
 For more about build flags, see 'go help build'.
 
 For more about specifying packages, see 'go help packages'.
@@ -75,6 +80,7 @@ var (
        cleanI         bool // clean -i flag
        cleanR         bool // clean -r flag
        cleanCache     bool // clean -cache flag
+       cleanModcache  bool // clean -modcache flag
        cleanTestcache bool // clean -testcache flag
 )
 
@@ -85,6 +91,7 @@ func init() {
        CmdClean.Flag.BoolVar(&cleanI, "i", false, "")
        CmdClean.Flag.BoolVar(&cleanR, "r", false, "")
        CmdClean.Flag.BoolVar(&cleanCache, "cache", false, "")
+       CmdClean.Flag.BoolVar(&cleanModcache, "modcache", false, "")
        CmdClean.Flag.BoolVar(&cleanTestcache, "testcache", false, "")
 
        // -n and -x are important enough to be
@@ -138,6 +145,29 @@ func runClean(cmd *base.Command, args []string) {
                        }
                }
        }
+
+       if cleanModcache {
+               if modfetch.SrcMod == "" {
+                       base.Fatalf("go clean -modcache: no module cache")
+               }
+               if err := removeAll(modfetch.SrcMod); err != nil {
+                       base.Errorf("go clean -modcache: %v", err)
+               }
+       }
+}
+
+func removeAll(dir string) error {
+       // Module cache has 0555 directories; make them writable in order to remove content.
+       filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+               if err != nil {
+                       return nil // ignore errors walking in file system
+               }
+               if info.IsDir() {
+                       os.Chmod(path, 0777)
+               }
+               return nil
+       })
+       return os.RemoveAll(dir)
 }
 
 var cleaned = map[*load.Package]bool{}

diff --git a/src/cmd/go/mod_test.go b/src/cmd/go/mod_test.go
index a15832faca5996f27d39d1fffd4c09e39206966c..3e8a01090ba4214f8fa22757ae96ed1004f62b62 100644 (file)
--- a/src/cmd/go/mod_test.go
+++ b/src/cmd/go/mod_test.go
@@ -1067,6 +1067,11 @@ func TestModList(t *testing.T) {
                t.Fatalf("%s should be unwritable", filepath.Join(dir, "buggy"))
        }
 
+       tg.run("clean", "-modcache")
+       if _, err = os.Stat(dir); err == nil {
+               t.Fatal("clean -modcache did not remove download dir")
+       }
+
        tg.must(ioutil.WriteFile(tg.path("x/go.mod"), []byte(`
                module x
                require rsc.io/quote v1.5.1