database/sql: avoid closing Rows while scan is in progress
A database/sql/driver.Rows can return database-owned data
from Rows.Next. The driver.Rows documentation doesn't explicitly
document the lifetime guarantees for this data, but a reasonable
expectation is that the caller of Next should only access it
until the next call to Rows.Close or Rows.Next.
Avoid violating that constraint when a query is cancelled while
a call to database/sql.Rows.Scan (note the difference between
the two different Rows types!) is in progress. We previously
took care to avoid closing a driver.Rows while the user has
access to driver-owned memory via a RawData, but we could still
close a driver.Rows while a Scan call was in the process of
reading previously-returned driver-owned data.
Update the fake DB used in database/sql tests to invalidate
returned data to help catch other places we might be
incorrectly retaining it.
Fixes #74831.
Change-Id: Ice45b5fad51b679c38e3e1d21ef39156b56d6037
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2540 Reviewed-by: Roland Shoemaker <bracewell@google.com> Reviewed-by: Neal Patel <nealpatel@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/693735
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Roland Shoemaker <roland@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>