From 995e97ff69a30ccdf885b4c25f11bbb368eca936 Mon Sep 17 00:00:00 2001
From: Adnan Gulegulzar <gulegulzaradnan@gmail.com>
Date: Sat, 20 Jul 2024 19:51:52 -0400
Subject: [PATCH] fix: updating error handling for non tar files

Signed-off-by: Adnan Gulegulzar <gulegulzaradnan@gmail.com>
---
 content/oci/readonlyoci_test.go      | 13 +++++++++++++
 content/oci/testdata/dummyfile       |  0
 errdef/errors.go                     |  1 +
 internal/fs/tarfs/tarfs.go           |  7 +++++++
 internal/fs/tarfs/tarfs_test.go      | 12 ++++++++++++
 internal/fs/tarfs/testdata/emptyfile |  0
 6 files changed, 33 insertions(+)
 create mode 100644 content/oci/testdata/dummyfile
 create mode 100644 internal/fs/tarfs/testdata/emptyfile

diff --git a/content/oci/readonlyoci_test.go b/content/oci/readonlyoci_test.go
index d7b4fd0ed..eaa030903 100644
--- a/content/oci/readonlyoci_test.go
+++ b/content/oci/readonlyoci_test.go
@@ -36,6 +36,7 @@ import (
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/content"
 	"oras.land/oras-go/v2/content/memory"
+	"oras.land/oras-go/v2/errdef"
 	"oras.land/oras-go/v2/internal/docker"
 	"oras.land/oras-go/v2/internal/spec"
 	"oras.land/oras-go/v2/registry"
@@ -836,3 +837,15 @@ func Test_deleteAnnotationRefName(t *testing.T) {
 		})
 	}
 }
+
+func TestNewFromTar_NonTarFile(t *testing.T) {
+
+	emptyfile := "testdata/emptyfile"
+
+	_, err := NewFromTar(context.Background(), emptyfile)
+
+	if want := errdef.ErrNotTarFile; !errors.Is(err, want) {
+		t.Errorf("OCI.NewFromTar(%s) error = %v, wantErr %v", emptyfile, err, want)
+	}
+
+}
diff --git a/content/oci/testdata/dummyfile b/content/oci/testdata/dummyfile
new file mode 100644
index 000000000..e69de29bb
diff --git a/errdef/errors.go b/errdef/errors.go
index 7adb44b17..78e7f8299 100644
--- a/errdef/errors.go
+++ b/errdef/errors.go
@@ -28,4 +28,5 @@ var (
 	ErrSizeExceedsLimit   = errors.New("size exceeds limit")
 	ErrUnsupported        = errors.New("unsupported")
 	ErrUnsupportedVersion = errors.New("unsupported version")
+	ErrNotTarFile         = errors.New("tar file type expected")
 )
diff --git a/internal/fs/tarfs/tarfs.go b/internal/fs/tarfs/tarfs.go
index a7a0a6c14..6d2fc6862 100644
--- a/internal/fs/tarfs/tarfs.go
+++ b/internal/fs/tarfs/tarfs.go
@@ -48,6 +48,13 @@ func New(path string) (*TarFS, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to resolve absolute path for %s: %w", path, err)
 	}
+
+	extension := filepath.Ext(pathAbs)
+
+	if extension != ".tar" {
+		return nil, errdef.ErrNotTarFile
+	}
+
 	tarfs := &TarFS{
 		path:    pathAbs,
 		entries: make(map[string]*entry),
diff --git a/internal/fs/tarfs/tarfs_test.go b/internal/fs/tarfs/tarfs_test.go
index 3a67b88c8..1cab2eb1d 100644
--- a/internal/fs/tarfs/tarfs_test.go
+++ b/internal/fs/tarfs/tarfs_test.go
@@ -268,3 +268,15 @@ func TestTarFS_Stat_Unsupported(t *testing.T) {
 		}
 	}
 }
+
+func TestTarFS_New_NonTarFile(t *testing.T) {
+
+	emptyfile := "testdata/emptyfile"
+
+	_, err := New(emptyfile)
+
+	if want := errdef.ErrNotTarFile; !errors.Is(err, want) {
+		t.Errorf("TarFS.New(%s) error = %v, wantErr %v", emptyfile, err, want)
+	}
+
+}
diff --git a/internal/fs/tarfs/testdata/emptyfile b/internal/fs/tarfs/testdata/emptyfile
new file mode 100644
index 000000000..e69de29bb