Revert "improve untar when using files instead of directories. Specifies behavior on non-existant targets."

This reverts commit 1c8d3106df.

Conflicts:
	archive/archive_test.go

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)

archive/archive.go

@@ -378,12 +378,10 @@ func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error)
 }
 
 // Untar reads a stream of bytes from `archive`, parses it as a tar archive,
-// and unpacks it into the directory at `dest`.
+// and unpacks it into the directory at `path`.
 // The archive may be compressed with one of the following algorithms:
 //  identity (uncompressed), gzip, bzip2, xz.
-// If `dest` does not exist, it is created unless there are multiple entries in `archive`.
+// FIXME: specify behavior when target path exists vs. doesn't exist.
-// In the latter case, an error is returned.
-// An other error is returned if `dest` exists but is not a directory, to prevent overwriting.
 func Untar(archive io.Reader, dest string, options *TarOptions) error {
 	if archive == nil {
 		return fmt.Errorf("Empty archive")
@@ -397,21 +395,7 @@ func Untar(archive io.Reader, dest string, options *TarOptions) error {
 
 	tr := tar.NewReader(decompressedArchive)
 
-	var (
+	var dirs []*tar.Header
-		dirs            []*tar.Header
-		destNotExist    bool
-		multipleEntries bool
-	)
-
-	if fi, err := os.Lstat(dest); err != nil {
-		if !os.IsNotExist(err) {
-			return err
-		}
-		// destination does not exist, so it is assumed it has to be created.
-		destNotExist = true
-	} else if !fi.IsDir() {
-		return fmt.Errorf("Trying to untar to `%s`: exists but not a directory", dest)
-	}
 
 	// Iterate through the files in the archive.
 	for {
@@ -424,11 +408,6 @@ func Untar(archive io.Reader, dest string, options *TarOptions) error {
 			return err
 		}
 
-		// Return an error if destination needs to be created and there is more than 1 entry in the tar stream.
-		if destNotExist && multipleEntries {
-			return fmt.Errorf("Trying to untar an archive with multiple entries to an inexistant target `%s`: did you mean `%s` instead?", dest, filepath.Dir(dest))
-		}
-
 		// Normalize name, for safety and for a simple is-root check
 		hdr.Name = filepath.Clean(hdr.Name)
 
@@ -444,12 +423,7 @@ func Untar(archive io.Reader, dest string, options *TarOptions) error {
 			}
 		}
 
-		var path string
+		path := filepath.Join(dest, hdr.Name)
-		if destNotExist {
-			path = dest // we are renaming hdr.Name to dest
-		} else {
-			path = filepath.Join(dest, hdr.Name)
-		}
 
 		// If path exits we almost always just want to remove and replace it
 		// The only exception is when it is a directory *and* the file from
@@ -469,9 +443,6 @@ func Untar(archive io.Reader, dest string, options *TarOptions) error {
 			return err
 		}
 
-		// Successfully added an entry. Predicting multiple entries for next iteration (not current one).
-		multipleEntries = true
-
 		// Directory mtimes must be handled at the end to avoid further
 		// file creation in them to modify the directory mtime
 		if hdr.Typeflag == tar.TypeDir {

archive/archive_test.go

@@ -160,44 +160,6 @@ func TestTarWithOptions(t *testing.T) {
 	}
 }
 
-func TestTarUntarFile(t *testing.T) {
-	origin, err := ioutil.TempDir("", "docker-test-untar-origin-file")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(origin)
-
-	if err := os.MkdirAll(path.Join(origin, "before"), 0700); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.MkdirAll(path.Join(origin, "after"), 0700); err != nil {
-		t.Fatal(err)
-	}
-	if err := ioutil.WriteFile(path.Join(origin, "before", "file"), []byte("hello world"), 0700); err != nil {
-		t.Fatal(err)
-	}
-
-	tar, err := TarWithOptions(path.Join(origin, "before"), &TarOptions{Compression: Uncompressed, Includes: []string{"file"}})
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if err := Untar(tar, path.Join(origin, "after", "file2"), nil); err != nil {
-		t.Fatal(err)
-	}
-
-	catCmd := exec.Command("cat", path.Join(origin, "after", "file2"))
-	out, err := CmdStream(catCmd, nil)
-	if err != nil {
-		t.Fatalf("Failed to start command: %s", err)
-	}
-	if output, err := ioutil.ReadAll(out); err != nil {
-		t.Error(err)
-	} else if string(output) != "hello world" {
-		t.Fatalf("Expected 'hello world', got '%s'", output)
-	}
-}
-
 // Some tar archives such as http://haproxy.1wt.eu/download/1.5/src/devel/haproxy-1.5-dev21.tar.gz
 // use PAX Global Extended Headers.
 // Failing prevents the archives from being uncompressed during ADD