database/sql: convert SQL null values to []byte as nil.
Also allow string values to scan into []byte.
Fixes #2788.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5577054
diff --git a/src/pkg/database/sql/convert.go b/src/pkg/database/sql/convert.go
index 9835e38..e80420e 100644
--- a/src/pkg/database/sql/convert.go
+++ b/src/pkg/database/sql/convert.go
@@ -40,6 +40,9 @@
case *string:
*d = s
return nil
+ case *[]byte:
+ *d = []byte(s)
+ return nil
}
case []byte:
switch d := dest.(type) {
@@ -50,6 +53,12 @@
*d = s
return nil
}
+ case nil:
+ switch d := dest.(type) {
+ case *[]byte:
+ *d = nil
+ return nil
+ }
}
var sv reflect.Value
diff --git a/src/pkg/database/sql/sql.go b/src/pkg/database/sql/sql.go
index 7e226b1..34a7652 100644
--- a/src/pkg/database/sql/sql.go
+++ b/src/pkg/database/sql/sql.go
@@ -904,6 +904,12 @@
if !ok {
continue
}
+ if *b == nil {
+ // If the []byte is now nil (for a NULL value),
+ // don't fall through to below which would
+ // turn it into a non-nil 0-length byte slice
+ continue
+ }
if _, ok = dp.(*RawBytes); ok {
continue
}
@@ -945,17 +951,10 @@
if r.err != nil {
return r.err
}
- defer r.rows.Close()
- if !r.rows.Next() {
- return ErrNoRows
- }
- err := r.rows.Scan(dest...)
- if err != nil {
- return err
- }
// TODO(bradfitz): for now we need to defensively clone all
- // []byte that the driver returned, since we're about to close
+ // []byte that the driver returned (not permitting
+ // *RawBytes in Rows.Scan), since we're about to close
// the Rows in our defer, when we return from this function.
// the contract with the driver.Next(...) interface is that it
// can return slices into read-only temporary memory that's
@@ -970,14 +969,17 @@
if _, ok := dp.(*RawBytes); ok {
return errors.New("sql: RawBytes isn't allowed on Row.Scan")
}
- b, ok := dp.(*[]byte)
- if !ok {
- continue
- }
- clone := make([]byte, len(*b))
- copy(clone, *b)
- *b = clone
}
+
+ defer r.rows.Close()
+ if !r.rows.Next() {
+ return ErrNoRows
+ }
+ err := r.rows.Scan(dest...)
+ if err != nil {
+ return err
+ }
+
return nil
}
diff --git a/src/pkg/database/sql/sql_test.go b/src/pkg/database/sql/sql_test.go
index 08db6d3..c5cadad 100644
--- a/src/pkg/database/sql/sql_test.go
+++ b/src/pkg/database/sql/sql_test.go
@@ -358,6 +358,34 @@
}
}
+// Tests fix for issue 2788, that we bind nil to a []byte if the
+// value in the column is sql null
+func TestNullByteSlice(t *testing.T) {
+ db := newTestDB(t, "")
+ defer closeDB(t, db)
+ exec(t, db, "CREATE|t|id=int32,name=nullstring")
+ exec(t, db, "INSERT|t|id=10,name=?", nil)
+
+ var name []byte
+
+ err := db.QueryRow("SELECT|t|name|id=?", 10).Scan(&name)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if name != nil {
+ t.Fatalf("name []byte should be nil for null column value, got: %#v", name)
+ }
+
+ exec(t, db, "INSERT|t|id=11,name=?", "bob")
+ err = db.QueryRow("SELECT|t|name|id=?", 11).Scan(&name)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if string(name) != "bob" {
+ t.Fatalf("name []byte should be bob, got: %q", string(name))
+ }
+}
+
func TestQueryRowClosingStmt(t *testing.T) {
db := newTestDB(t, "people")
defer closeDB(t, db)
