From 3dbef65bf37f1b7ccd1f884761341a5a15456ffa Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Sat, 31 May 2025 15:27:15 +0000
Subject: database/sql: allow drivers to override Scan behavior

Implementing RowsColumnScanner allows the driver
to completely control how values are scanned.

Fixes #67546

Change-Id: Id8e7c3a973479c9665e4476fe2d29e1255aee687
GitHub-Last-Rev: ed0cacaec4a4feead56b09c0d6eee86ed58fe1ee
GitHub-Pull-Request: golang/go#67648
Reviewed-on: https://go-review.googlesource.com/c/go/+/588435
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Sean Liao <sean@liao.dev>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---
 src/database/sql/sql.go | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'src/database/sql/sql.go')

diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go
index 4be450ca87..85b9ffc37d 100644
--- a/src/database/sql/sql.go
+++ b/src/database/sql/sql.go
@@ -3396,7 +3396,16 @@ func (rs *Rows) scanLocked(dest ...any) error {
 	}
 
 	for i, sv := range rs.lastcols {
-		err := convertAssignRows(dest[i], sv, rs)
+		err := driver.ErrSkip
+
+		if rcs, ok := rs.rowsi.(driver.RowsColumnScanner); ok {
+			err = rcs.ScanColumn(dest[i], i)
+		}
+
+		if err == driver.ErrSkip {
+			err = convertAssignRows(dest[i], sv, rs)
+		}
+
 		if err != nil {
 			return fmt.Errorf(`sql: Scan error on column index %d, name %q: %w`, i, rs.rowsi.Columns()[i], err)
 		}
-- 
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