From daf2efa3137769714e3347a1d95ac00f6ed7a6e9 Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Tue, 23 Dec 2014 21:58:48 -0600
Subject: [PATCH] Tweak handling of reading null as raw bytes.

* NULL maps to nil not empty slice
* Handle NULL in Scan not ReadBytes
---
 query.go        | 6 +++++-
 query_test.go   | 8 ++++----
 value_reader.go | 3 ++-
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/query.go b/query.go
index 8f7e672a..591303ce 100644
--- a/query.go
+++ b/query.go
@@ -227,7 +227,11 @@ func (rows *Rows) Scan(dest ...interface{}) (err error) {
 			if vr.Type().DataType == ByteaOid {
 				*d = decodeBytea(vr)
 			} else {
-				*d = vr.ReadBytes(vr.Len())
+				if vr.Len() != -1 {
+					*d = vr.ReadBytes(vr.Len())
+				} else {
+					*d = nil
+				}
 			}
 		case *int64:
 			*d = decodeInt8(vr)
diff --git a/query_test.go b/query_test.go
index 6cb384df..f5688b11 100644
--- a/query_test.go
+++ b/query_test.go
@@ -817,8 +817,8 @@ func TestReadingNullByteArray(t *testing.T) {
 		t.Fatalf("conn.QueryRow failed: ", err)
 	}
 
-	if len(a) != 0 {
-		t.Errorf("Expected 'a' to have length 0, but it was: ", len(a))
+	if a != nil {
+		t.Errorf("Expected 'a' to be nil, but it was: %v", a)
 	}
 }
 
@@ -838,8 +838,8 @@ func TestReadingNullByteArrays(t *testing.T) {
 		if err := rows.Scan(&a); err != nil {
 			t.Fatalf("failed to scan row", err)
 		}
-		if len(a) != 0 {
-			t.Errorf("Expected 'a' to have length 0, but it was: ", len(a))
+		if a != nil {
+			t.Errorf("Expected 'a' to be nil, but it was: %v", a)
 		}
 	}
 	if count != 2 {
diff --git a/value_reader.go b/value_reader.go
index 3b388825..359f2f7e 100644
--- a/value_reader.go
+++ b/value_reader.go
@@ -113,7 +113,8 @@ func (r *ValueReader) ReadBytes(count int32) []byte {
 		return nil
 	}
 
-	if count == -1 {
+	if count < 0 {
+		r.Fatal(errors.New("count must not be negative"))
 		return nil
 	}