stmt.QueryRowContext doesn't respect canceled context

[michaelshobbs]

Working on a project using https://github.com/jmoiron/sqlx, I ran into this issue when using PrepareContext()/QueryRowContext with a context with timeout.

The following test case exercises the problem

func TestIssue1046(t *testing.T) {
	ctxTimeout := time.Second * 2
	sleepSQL := `SELECT pg_sleep(10) AS id`

	db := openTestConn(t)
	defer db.Close()

	ctx, cancel := context.WithTimeout(context.Background(), ctxTimeout)
	defer cancel()

	stmt, err := db.PrepareContext(ctx, sleepSQL)
	if err != nil {
		t.Fatal(err)
	}

	var d []uint8
	err = stmt.QueryRowContext(ctx).Scan(&d)
	dl, _ := ctx.Deadline()
	since := time.Since(dl)
	if since > ctxTimeout {
		t.Logf("FAIL %s: query returned after context deadline: %v\n", t.Name(), since)
		t.Fail()
	}
	expectedErr := &Error{Message: "canceling statement due to user request"}
	if err == nil || err.Error() != expectedErr.Error() {
		t.Logf("ctx.Err(): [%T]%+v\n", ctx.Err(), ctx.Err())
		t.Logf("got err: [%T] %+v expected err: [%T] %+v", err, err, expectedErr, expectedErr)
		t.Fail()
	}
}

[michaelshobbs]

I found #921 and pulling that into master locally seems to resolve the issue. I'll open up a new PR and add test cases