Merge pull request #38 from vinyl-linux/ensure_links

Ensure links

os.go

@@ -209,12 +209,25 @@ func decompressLoop(tr *tar.Reader, dest string) (err error) {
 			f.Close()
 
 		case tar.TypeLink:
-			err = os.Link(header.Linkname, target)
+			// remove target if it exists.
+			//
+			// ignoring the error is fine here; if there's an error
+			// we'll see it when we try to link anyway /shrug
+			os.Remove(target)
+
+			err = os.Link(filepath.Join(dest, header.Linkname), target)
 			if err != nil {
 				return
 			}
 
 		case tar.TypeSymlink:
+			// see comment for the tar.TypeLink case above;
+			os.Remove(target)
+
+			// we don't need to worry about prefixing synlinks. Infact,
+			// we probably don't want that at all. symlinks can point to
+			// files that don't exist, and probably want to be more flexible
+			// for things like relative links anyway
 			err = os.Symlink(header.Linkname, target)
 			if err != nil {
 				return

os_test.go

@@ -51,19 +51,20 @@ func TestUntar(t *testing.T) {
 }
 
 func TestUntar_WithLinks(t *testing.T) {
-	dir := "testdata"
-
-	err := untar("testdata/complex.tar.bz2", dir)
+	dir, err := ioutil.TempDir("", "")
 	if err != nil {
 		t.Fatalf("unexpected error: %+v", err)
 	}
 
-	defer os.RemoveAll("testdata/testdata")
+	err = untar("testdata/complex.tar.bz2", dir)
+	if err != nil {
+		t.Fatalf("unexpected error: %+v", err)
+	}
 
 	t.Run("checksum", func(t *testing.T) {
 		expect := "9fbefb949709fc7086ab4be43544d08406f0ededa0733f6683424e774a6cb799"
 
-		sum, err := checksum(filepath.Join(dir, "testdata", "raw"))
+		sum, err := checksum(filepath.Join(dir, "raw"))
 		if err != nil {
 			t.Fatalf("unexpected error: %+v", err)
 		}
@@ -74,14 +75,14 @@ func TestUntar_WithLinks(t *testing.T) {
 	})
 
 	t.Run("hard links", func(t *testing.T) {
-		_, err := os.Stat(filepath.Join(dir, "testdata", "hardlink"))
+		_, err := os.Stat(filepath.Join(dir, "hardlink"))
 		if err != nil {
 			t.Fatalf("unexpected error: %+v", err)
 		}
 	})
 
 	t.Run("symlinks", func(t *testing.T) {
-		_, err := os.Stat(filepath.Join(dir, "testdata", "symlink"))
+		_, err := os.Stat(filepath.Join(dir, "symlink"))
 		if err != nil {
 			t.Fatalf("unexpected error: %+v", err)
 		}