cmd/go/internal/vgo: fix handling of vendor dir in package patterns

A directory x/vendor containing code is just a package called vendor.
A directory x/vendor/y is vendored code.
When a package pattern scans the current module's file tree
it should include a package called vendor but should not
include the directories containing vendored code.

Maybe related to a comment on golang/go#25624.

Change-Id: I083a98a9c70c2121cff7a2f394ff985a54bed37a
Reviewed-on: https://go-review.googlesource.com/116759
Run-TryBot: Russ Cox <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Bryan C. Mills <[email protected]>

Author: rsc

vendor/cmd/go/internal/vgo/search.go

@@ -131,22 +131,18 @@ func matchPackages(pattern string, buildList []module.Version) []string {
 				return filepath.SkipDir
 			}
 
-			if have[name] {
-				return nil
-			}
-			have[name] = true
-			if !match(name) {
-				return nil
-			}
-			if _, _, err := imports.ScanDir(path, imports.Tags()); err == imports.ErrNoGo {
-				return nil
+			if !have[name] {
+				have[name] = true
+				if match(name) {
+					if _, _, err := imports.ScanDir(path, imports.Tags()); err != imports.ErrNoGo {
+						pkgs = append(pkgs, name)
+					}
+				}
 			}
 
 			if elem == "vendor" {
-				return filepath.SkipDir // ignore children
+				return filepath.SkipDir
 			}
-
-			pkgs = append(pkgs, name)
 			return nil
 		})
 	}

vendor/cmd/go/vgo_test.go

@@ -137,6 +137,27 @@ func TestTags(t *testing.T) {
 	tg.grepStdout(`\[x.go y.go\]`, "Go source files for tag1 and tag2")
 }
 
+func TestAllVsVendor(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.makeTempdir()
+
+	tg.must(os.MkdirAll(tg.path("x/vendor/v"), 0777))
+	tg.must(ioutil.WriteFile(tg.path("x/go.mod"), []byte(`
+		module m
+	`), 0666))
+
+	tg.must(ioutil.WriteFile(tg.path("x/x.go"), []byte(`package x`), 0666))
+	tg.must(ioutil.WriteFile(tg.path("x/vendor/v/v.go"), []byte(`package v; import "golang.org/x/crypto"`), 0666))
+	tg.must(ioutil.WriteFile(tg.path("x/vendor/v.go"), []byte(`package main`), 0666))
+
+	tg.cd(tg.path("x"))
+	tg.run("-vgo", "list", "all")
+	tg.grepStdout(`^m$`, "expected m")
+	tg.grepStdout(`^m/vendor$`, "must see package named vendor")
+	tg.grepStdoutNot(`vendor/`, "must not see vendored packages")
+}
+
 func TestFillGoMod(t *testing.T) {
 	testenv.MustHaveExternalNetwork(t)
 	tg := testgo(t)