Merge pull request #905 from poy/fixes/904

when copying, skip files with the same name

pkg/util/fs_util.go

@@ -551,6 +551,12 @@ func CopyFile(src, dest, buildcontext string) (bool, error) {
 		logrus.Debugf("%s found in .dockerignore, ignoring", src)
 		return true, nil
 	}
+	if src == dest {
+		// This is a no-op. Move on, but don't list it as ignored.
+		// We have to make sure we do this so we don't overwrite our own file.
+		// See iusse #904 for an example.
+		return false, nil
+	}
 	fi, err := os.Stat(src)
 	if err != nil {
 		return false, err

pkg/util/fs_util_test.go

@@ -825,3 +825,41 @@ func Test_correctDockerignoreFileIsUsed(t *testing.T) {
 		}
 	}
 }
+
+func Test_CopyFile_skips_self(t *testing.T) {
+	t.Parallel()
+	tempDir, err := ioutil.TempDir("", "kaniko_test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tempFile := filepath.Join(tempDir, "foo")
+	expected := "bar"
+
+	if err := ioutil.WriteFile(
+		tempFile,
+		[]byte(expected),
+		0755,
+	); err != nil {
+		t.Fatal(err)
+	}
+
+	ignored, err := CopyFile(tempFile, tempFile, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if ignored {
+		t.Fatal("expected file to NOT be ignored")
+	}
+
+	// Ensure file has expected contents
+	actualData, err := ioutil.ReadFile(tempFile)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if actual := string(actualData); actual != expected {
+		t.Fatalf("expected file contents to be %q, but got %q", expected, actual)
+	}
+}