cmd/godoc: don't execute go mod download when GOMOD is /dev/null
When the GOMOD value is the operating system's null device, there
isn't a main module and thus there cannot be module requirements.
Don't try to fill module cache, since running 'go mod download'
would cause a "no modules specified (see 'go help mod download')"
error to be printed, which is confusing.
Fixes golang/go#35476
Change-Id: Ia1f5ee50797a4dc3e36c3b9773e19da781bd9d39
Reviewed-on: https://go-review.googlesource.com/c/tools/+/206886
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
diff --git a/cmd/godoc/godoc_test.go b/cmd/godoc/godoc_test.go
index 3654e37..3748388 100644
--- a/cmd/godoc/godoc_test.go
+++ b/cmd/godoc/godoc_test.go
@@ -182,7 +182,7 @@
cmd.Stderr = stderr
cmd.Args[0] = "godoc"
- // Set GOPATH variable to non-existing absolute path
+ // Set GOPATH variable to a non-existing absolute path
// and GOPROXY=off to disable module fetches.
// We cannot just unset GOPATH variable because godoc would default it to ~/go.
// (We don't want the indexer looking at the local workspace during tests.)
@@ -444,6 +444,38 @@
}
}
+// Test for golang.org/issue/35476.
+func TestNoMainModule(t *testing.T) {
+ if testing.Short() {
+ t.Skip("skipping test in -short mode")
+ }
+ if runtime.GOOS == "plan9" {
+ t.Skip("skipping on plan9; for consistency with other tests that build godoc binary")
+ }
+ bin, cleanup := buildGodoc(t)
+ defer cleanup()
+ tempDir, err := ioutil.TempDir("", "godoc-test-")
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer os.RemoveAll(tempDir)
+
+ // Run godoc in an empty directory with module mode explicitly on,
+ // so that 'go env GOMOD' reports os.DevNull.
+ cmd := exec.Command(bin, "-url=/")
+ cmd.Dir = tempDir
+ cmd.Env = append(os.Environ(), "GO111MODULE=on")
+ var stderr bytes.Buffer
+ cmd.Stderr = &stderr
+ err = cmd.Run()
+ if err != nil {
+ t.Fatal(err)
+ }
+ if strings.Contains(stderr.String(), "go mod download") {
+ t.Errorf("stderr contains 'go mod download', is that intentional?\nstderr=%q", stderr.String())
+ }
+}
+
// Basic integration test for godoc -analysis=type (via HTTP interface).
func TestTypeAnalysis(t *testing.T) {
bin, cleanup := buildGodoc(t)
diff --git a/cmd/godoc/main.go b/cmd/godoc/main.go
index 082fda8..1d402ba 100644
--- a/cmd/godoc/main.go
+++ b/cmd/godoc/main.go
@@ -222,7 +222,7 @@
// This may fail if module downloading is disallowed (GOPROXY=off) or due to
// limited connectivity, in which case we print errors to stderr and show
// documentation only for packages that are available.
- fillModuleCache(os.Stderr)
+ fillModuleCache(os.Stderr, goModFile)
// Determine modules in the build list.
mods, err := buildList()
@@ -414,7 +414,12 @@
// It should only be used when operating in module mode.
//
// See https://golang.org/cmd/go/#hdr-Download_modules_to_local_cache.
-func fillModuleCache(w io.Writer) {
+func fillModuleCache(w io.Writer, goMod string) {
+ if goMod == os.DevNull {
+ // No module requirements, nothing to do.
+ return
+ }
+
cmd := exec.Command("go", "mod", "download", "-json")
var out bytes.Buffer
cmd.Stdout = &out
