Do not reuse sql driver's buffer in scanner. Fixes #298.

Signed-off-by: Howard Yeh <[email protected]>

types/slices.go

@@ -653,7 +653,20 @@ type ByteArray []uint8
 func (a *ByteArray) Scan(src interface{}) error {
 	switch src := src.(type) {
 	case []byte:
-		*(*[]byte)(a) = src
+		dst := *(*[]byte)(a)
+
+		if a == nil || cap(dst) < len(src) {
+			// nil, or shorter destination than source. Create a new slice.
+			dst = make([]byte, len(src))
+		} else {
+			// Resize slice, but retain capacity
+			dst = dst[0:len(src)]
+		}
+
+		// Copy, do not retain reference to reference types.
+		copy(dst, src)
+
+		*(*[]byte)(a) = dst
 		return nil
 	case string:
 		*(*[]byte)(a) = []byte(src)

types/slices_test.go

@@ -207,6 +207,23 @@ func TestSlice_Integration(t *testing.T) {
 	}
 }
 
+func TestByteArray_ScannerNoBufferReuse(t *testing.T) {
+	require := require.New(t)
+
+	var sharedbuf [32]byte
+
+	var ba ByteArray
+
+	err := ba.Scan(sharedbuf[:])
+	require.NoError(err)
+
+	// Modify the "driver" buffer src
+	sharedbuf[0] = 1
+
+	require.Equal(uint8(0), ba[0], "ByteBuffer should not share reference with scanned src")
+
+}
+
 func envOrDefault(key string, def string) string {
 	v := os.Getenv(key)
 	if v == "" {