code review 5539060: exp/sql: copy when scanning into []byte by default

exp/sql: copy when scanning into []byte by default

Fixes issue 2698

[bradfitz, 2012-01-14 00:17:29]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[rsc, 2012-01-17 00:16:05]

LGTM

http://codereview.appspot.com/5539060/diff/4003/src/pkg/exp/sql/sql.go
File src/pkg/exp/sql/sql.go (right):

http://codereview.appspot.com/5539060/diff/4003/src/pkg/exp/sql/sql.go#newcode33
src/pkg/exp/sql/sql.go:33: // RawBytes is a byte slice that signals to Rows.Scan
that you don't want a copy
// RawBytes is a byte slice that holds a reference to memory owned by
// the database itself.  After a Scan into a RawBytes, the slice is only
// valid until the next call to Next, Scan, or Close.

http://codereview.appspot.com/5539060/diff/4003/src/pkg/exp/sql/sql.go#newcod...
src/pkg/exp/sql/sql.go:770: // If dest contains pointers to []byte, a copy is
performed and the
// If an argument has type *[]byte, Scan saves in that argument a copy
// of the corresponding data.  The copy is owned by the caller and can
// be modified and held indefinitely.  The copy can be avoided by using 
// an argument of type *RawBytes instead; see the documentation for
// RawBytes for restrictions on its use.

[bradfitz, 2012-01-17 18:44:38]

*** Submitted as http://code.google.com/p/go/source/detail?r=62ffb469677e ***

exp/sql: copy when scanning into []byte by default

Fixes issue 2698

R=rsc
CC=golang-dev
http://codereview.appspot.com/5539060