imports: try importing pkg path from vendor when looking for pkg name

Since CL 17728 goimports was using the file path to try finding packages
inside its /vendor directory. This CL builds upon this previous work to
also consider packages inside /vendor when converting an import path to
a package name.

Change-Id: I173472ac51e3f681d758ec52add60ffc04c62c1a
Reviewed-on: https://go-review.googlesource.com/22020
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

imports/fix.go

@@ -54,6 +54,12 @@ func fixImports(fset *token.FileSet, f *ast.File, filename string) (added []stri
 	// decls are the current package imports. key is base package or renamed package.
 	decls := make(map[string]*ast.ImportSpec)
 
+	abs, err := filepath.Abs(filename)
+	if err != nil {
+		return nil, err
+	}
+	srcDir := path.Dir(abs)
+
 	// collect potential uses of packages.
 	var visitor visitFn
 	visitor = visitFn(func(node ast.Node) ast.Visitor {
@@ -65,7 +71,7 @@ func fixImports(fset *token.FileSet, f *ast.File, filename string) (added []stri
 			if v.Name != nil {
 				decls[v.Name.Name] = v
 			} else {
-				local := importPathToName(strings.Trim(v.Path.Value, `\"`))
+				local := importPathToName(strings.Trim(v.Path.Value, `\"`), srcDir)
 				decls[local] = v
 			}
 		case *ast.SelectorExpr:
@@ -152,17 +158,17 @@ func fixImports(fset *token.FileSet, f *ast.File, filename string) (added []stri
 var importPathToName = importPathToNameGoPath
 
 // importPathToNameBasic assumes the package name is the base of import path.
-func importPathToNameBasic(importPath string) (packageName string) {
+func importPathToNameBasic(importPath, srcDir string) (packageName string) {
 	return path.Base(importPath)
 }
 
 // importPathToNameGoPath finds out the actual package name, as declared in its .go files.
 // If there's a problem, it falls back to using importPathToNameBasic.
-func importPathToNameGoPath(importPath string) (packageName string) {
-	if buildPkg, err := build.Import(importPath, "", 0); err == nil {
+func importPathToNameGoPath(importPath, srcDir string) (packageName string) {
+	if buildPkg, err := build.Import(importPath, srcDir, 0); err == nil {
 		return buildPkg.Name
 	} else {
-		return importPathToNameBasic(importPath)
+		return importPathToNameBasic(importPath, srcDir)
 	}
 }
 
@@ -260,7 +266,7 @@ func loadPkg(wg *sync.WaitGroup, root, pkgrelpath string) {
 		}
 	}
 	if hasGo {
-		shortName := importPathToName(importpath)
+		shortName := importPathToName(importpath, "")
 		pkgIndex.Lock()
 		pkgIndex.m[shortName] = append(pkgIndex.m[shortName], pkg{
 			importpath: importpath,

imports/fix_test.go

@@ -823,6 +823,60 @@ func TestFixImports(t *testing.T) {
 	}
 }
 
+// Test for correctly identifying the name of a vendored package when it
+// differs from its directory name. In this test, the import line
+// "mypkg.com/mypkg.v1" would be removed if goimports wasn't able to detect
+// that the package name is "mypkg".
+func TestFixImportsVendorPackage(t *testing.T) {
+	// Skip this test on go versions with no vendor support.
+	if _, err := os.Stat(filepath.Join(runtime.GOROOT(), "src/vendor")); err != nil {
+		t.Skip(err)
+	}
+
+	newGoPath, err := ioutil.TempDir("", "vendortest")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(newGoPath)
+
+	vendoredPath := newGoPath + "/src/mypkg.com/outpkg/vendor/mypkg.com/mypkg.v1"
+	if err := os.MkdirAll(vendoredPath, 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	pkgIndexOnce = &sync.Once{}
+	oldGOPATH := build.Default.GOPATH
+	build.Default.GOPATH = newGoPath
+	defer func() {
+		build.Default.GOPATH = oldGOPATH
+	}()
+
+	if err := ioutil.WriteFile(vendoredPath+"/f.go", []byte("package mypkg\nvar Foo = 123\n"), 0666); err != nil {
+		t.Fatal(err)
+	}
+
+	input := `package p
+
+import (
+	"fmt"
+
+	"mypkg.com/mypkg.v1"
+)
+
+var (
+	_ = fmt.Print
+	_ = mypkg.Foo
+)
+`
+	buf, err := Process(newGoPath+"/src/mypkg.com/outpkg/toformat.go", []byte(input), &Options{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := string(buf); got != input {
+		t.Fatalf("results differ\nGOT:\n%s\nWANT:\n%s\n", got, input)
+	}
+}
+
 func TestFindImportGoPath(t *testing.T) {
 	goroot, err := ioutil.TempDir("", "goimports-")
 	if err != nil {