types: fix issue that we can insert negative value to unsinged float column sometimes (#47946) (#47983)

close #47945

Author: ti-chi-bot

pkg/executor/insert_test.go

@@ -1593,3 +1593,16 @@ func TestInsertLockUnchangedKeys(t *testing.T) {
 		}
 	}
 }
+
+// see issue: https://github.com/pingcap/tidb/issues/47945
+func TestUnsignedDecimalFloatInsertNegative(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec("create table tf(a float(1, 0) unsigned)")
+	err := tk.ExecToErr("insert into tf values('-100')")
+	require.EqualError(t, err, "[types:1264]Out of range value for column 'a' at row 1")
+	tk.MustExec("set @@sql_mode=''")
+	tk.MustExec("insert into tf values('-100')")
+	tk.MustQuery("select * from tf").Check(testkit.Rows("0"))
+}

pkg/expression/builtin_cast.go

@@ -1419,7 +1419,7 @@ func (b *builtinCastStringAsRealSig) evalReal(row chunk.Row) (res float64, isNul
 	if b.inUnion && mysql.HasUnsignedFlag(b.tp.GetFlag()) && res < 0 {
 		res = 0
 	}
-	res, err = types.ProduceFloatWithSpecifiedTp(res, b.tp, sc)
+	res, err = types.ProduceFloatWithSpecifiedTp(res, b.tp)
 	return res, false, err
 }
 

pkg/expression/builtin_cast_vec.go

@@ -1692,7 +1692,7 @@ func (b *builtinCastStringAsRealSig) vecEvalReal(input *chunk.Chunk, result *chu
 		if b.inUnion && mysql.HasUnsignedFlag(b.tp.GetFlag()) && res < 0 {
 			res = 0
 		}
-		res, err = types.ProduceFloatWithSpecifiedTp(res, b.tp, sc)
+		res, err = types.ProduceFloatWithSpecifiedTp(res, b.tp)
 		if err != nil {
 			return err
 		}

pkg/types/datum.go

@@ -980,7 +980,7 @@ func (d *Datum) convertToFloat(sc *stmtctx.StatementContext, target *FieldType)
 	default:
 		return invalidConv(d, target.GetType())
 	}
-	f, err1 := ProduceFloatWithSpecifiedTp(f, target, sc)
+	f, err1 := ProduceFloatWithSpecifiedTp(f, target)
 	if err == nil && err1 != nil {
 		err = err1
 	}
@@ -993,7 +993,7 @@ func (d *Datum) convertToFloat(sc *stmtctx.StatementContext, target *FieldType)
 }
 
 // ProduceFloatWithSpecifiedTp produces a new float64 according to `flen` and `decimal`.
-func ProduceFloatWithSpecifiedTp(f float64, target *FieldType, sc *stmtctx.StatementContext) (_ float64, err error) {
+func ProduceFloatWithSpecifiedTp(f float64, target *FieldType) (_ float64, err error) {
 	if math.IsNaN(f) {
 		return 0, overflow(f, target.GetType())
 	}
@@ -1004,13 +1004,17 @@ func ProduceFloatWithSpecifiedTp(f float64, target *FieldType, sc *stmtctx.State
 	// If no D is set, we will handle it like origin float whether M is set or not.
 	if target.GetFlen() != UnspecifiedLength && target.GetDecimal() != UnspecifiedLength {
 		f, err = TruncateFloat(f, target.GetFlen(), target.GetDecimal())
-		if err = sc.HandleOverflow(err, err); err != nil {
-			return f, errors.Trace(err)
-		}
 	}
 	if mysql.HasUnsignedFlag(target.GetFlag()) && f < 0 {
 		return 0, overflow(f, target.GetType())
 	}
+
+	if err != nil {
+		// We must return the error got from TruncateFloat after checking whether the target is unsigned to make sure
+		// the returned float is not negative when the target type is unsigned.
+		return f, errors.Trace(err)
+	}
+
 	if target.GetType() == mysql.TypeFloat && (f > math.MaxFloat32 || f < -math.MaxFloat32) {
 		if f > 0 {
 			return math.MaxFloat32, overflow(f, target.GetType())