From 075a47e17652ffcc976f032fece82322bee0ead8 Mon Sep 17 00:00:00 2001
From: jiyfhust <jiyfhust@163.com>
Date: Fri, 28 Jul 2023 18:43:34 +0800
Subject: [PATCH] types: fix convert float to uint (#42063)

close pingcap/tidb#41733
---
 .../integration_serial_test.go                |  2 +-
 .../integration_test/integration_test.go      | 33 +++++++++++++++++++
 types/convert.go                              | 16 +++------
 3 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/expression/integration_serial_test/integration_serial_test.go b/expression/integration_serial_test/integration_serial_test.go
index 4ef1c68606..8ffa5c1255 100644
--- a/expression/integration_serial_test/integration_serial_test.go
+++ b/expression/integration_serial_test/integration_serial_test.go
@@ -3060,7 +3060,7 @@ func TestBuiltin(t *testing.T) {
 	_ = tk.MustQuery(`select * from tb5 where cast(a as unsigned int)=b;`)
 	// TODO `obtained string = "[18446744073709552000 18446744073709551615]`
 	// result.Check(testkit.Rows("18446744073709551616 18446744073709551615"))
-	tk.MustQuery("show warnings;").Check(testkit.Rows())
+	tk.MustQuery("show warnings;").Check(testkit.Rows("Warning 1690 constant 1.8446744073709552e+19 overflows bigint"))
 	tk.MustExec(`drop table tb5;`)
 
 	// test builtinCastJSONAsIntSig
diff --git a/expression/integration_test/integration_test.go b/expression/integration_test/integration_test.go
index 652c4a75cb..b42aa4e360 100644
--- a/expression/integration_test/integration_test.go
+++ b/expression/integration_test/integration_test.go
@@ -7954,3 +7954,36 @@ func TestIfFunctionWithNull(t *testing.T) {
 	tk.MustQuery("select min(if(apply_to_now_days <= 30,loan,null)) as min, max(if(apply_to_now_days <= 720,loan,null)) as max from (select loan, datediff(from_unixtime(unix_timestamp('2023-05-18 18:43:43') + 18000), from_unixtime(apply_time/1000 + 18000)) as apply_to_now_days from orders) t1;").Sort().Check(
 		testkit.Rows("20000 35100"))
 }
+
+func TestIssue41733(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("create database testIssue41733")
+	defer tk.MustExec("drop database testIssue41733")
+	tk.MustExec("use testIssue41733")
+
+	tk.MustExec("create table t_tiny (c0 TINYINT UNSIGNED)")
+	tk.MustExec("INSERT IGNORE INTO t_tiny(c0) VALUES (1E9)")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1264 Out of range value for column 'c0' at row 1"))
+	tk.MustQuery("select * from t_tiny;").Check(testkit.Rows("255"))
+
+	tk.MustExec("create table t_small (c0 SMALLINT UNSIGNED)")
+	tk.MustExec("INSERT IGNORE INTO t_small(c0) VALUES (1E9)")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1264 Out of range value for column 'c0' at row 1"))
+	tk.MustQuery("select * from t_small;").Check(testkit.Rows("65535"))
+
+	tk.MustExec("create table t_medium (c0 MEDIUMINT UNSIGNED)")
+	tk.MustExec("INSERT IGNORE INTO t_medium(c0) VALUES (1E9)")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1264 Out of range value for column 'c0' at row 1"))
+	tk.MustQuery("select * from t_medium;").Check(testkit.Rows("16777215"))
+
+	tk.MustExec("create table t_int (c0 INT UNSIGNED)")
+	tk.MustExec("INSERT IGNORE INTO t_int(c0) VALUES (1E20)")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1264 Out of range value for column 'c0' at row 1"))
+	tk.MustQuery("select * from t_int;").Check(testkit.Rows("4294967295"))
+
+	tk.MustExec("create table t_big (c0 BIGINT UNSIGNED)")
+	tk.MustExec("INSERT IGNORE INTO t_big(c0) VALUES (1E20)")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1264 Out of range value for column 'c0' at row 1"))
+	tk.MustQuery("select * from t_big;").Check(testkit.Rows("18446744073709551615"))
+}
diff --git a/types/convert.go b/types/convert.go
index 862997c231..572333433b 100644
--- a/types/convert.go
+++ b/types/convert.go
@@ -20,6 +20,7 @@ package types
 
 import (
 	"math"
+	"math/big"
 	"strconv"
 	"strings"
 
@@ -175,18 +176,11 @@ func ConvertFloatToUint(sc *stmtctx.StatementContext, fval float64, upperBound u
 		return uint64(int64(val)), overflow(val, tp)
 	}
 
-	ubf := float64(upperBound)
-	// Because math.MaxUint64 can not be represented precisely in iee754(64bit),
-	// so `float64(math.MaxUint64)` will make a num bigger than math.MaxUint64,
-	// which can not be represented by 64bit integer.
-	// So `uint64(float64(math.MaxUint64))` is undefined behavior.
-	if val == ubf {
-		return math.MaxUint64, nil
+	ret, acc := new(big.Float).SetFloat64(val).Uint64()
+	if acc == big.Below || ret > upperBound {
+		return upperBound, overflow(val, tp)
 	}
-	if val > ubf {
-		return math.MaxUint64, overflow(val, tp)
-	}
-	return uint64(val), nil
+	return ret, nil
 }
 
 // convertScientificNotation converts a decimal string with scientific notation to a normal decimal string.