types: fix undefined behavior in numeric types cast (cast 1<<64 to ui…

…nt64) (#11968) (#16239)
pingcap · Apr 10, 2020 · f03ea0f · f03ea0f
1 parent d82cf4c
commit f03ea0f
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Showing 4 changed files with 18 additions and 3 deletions.
diff --git a/expression/builtin_cast.go b/expression/builtin_cast.go
@@ -755,6 +755,10 @@ func (b *builtinCastRealAsIntSig) evalInt(row chunk.Row) (res int64, isNull bool
 		uintVal, err = types.ConvertFloatToUint(sc, val, types.IntergerUnsignedUpperBound(mysql.TypeLonglong), mysql.TypeLonglong)
 		res = int64(uintVal)
 	}
+	err = b.ctx.GetSessionVars().StmtCtx.HandleOverflow(err, err)
+	if err != nil {
+		return res, false, err
+	}
 	return res, isNull, err
 }
 

diff --git a/expression/integration_test.go b/expression/integration_test.go
@@ -2213,6 +2213,13 @@ func (s *testIntegrationSuite) TestBuiltin(c *C) {
 	c.Assert(last, Equals, "bigint")
 	tk.MustExec(`drop table tb5;`)
 
+	tk.MustExec(`create table tb5(a double(64));`)
+	tk.MustExec(`insert into test.tb5 (a) values (18446744073709551616);`)
+	tk.MustExec(`insert into test.tb5 (a) values (184467440737095516160);`)
+	result = tk.MustQuery(`select cast(a as unsigned) from test.tb5;`)
+	result.Check(testkit.Rows("9223372036854775807", "9223372036854775807"))
+	tk.MustExec(`drop table tb5`)
+
 	// test builtinCastIntAsDecimalSig
 	tk.MustExec(`create table tb5(a bigint(64) unsigned, b decimal(64, 10));`)
 	tk.MustExec(`insert into tb5 (a, b) values (9223372036854775808, 9223372036854775808);`)

diff --git a/types/convert.go b/types/convert.go
@@ -168,8 +168,12 @@ func ConvertFloatToUint(sc *stmtctx.StatementContext, fval float64, upperBound u
 		return uint64(int64(val)), overflow(val, tp)
 	}
 
-	if val > float64(upperBound) {
-		return upperBound, overflow(val, tp)
+	ubf := float64(upperBound)
+	if val == ubf {
+		return uint64(math.MaxInt64), nil
+	}
+	if val > ubf {
+		return uint64(math.MaxInt64), overflow(val, tp)
 	}
 	return uint64(val), nil
 }

diff --git a/types/convert_test.go b/types/convert_test.go
@@ -612,7 +612,7 @@ func (s *testTypeConvertSuite) TestConvert(c *C) {
 	unsignedAccept(c, mysql.TypeLonglong, -1, "18446744073709551615")
 	unsignedAccept(c, mysql.TypeLonglong, 0, "0")
 	unsignedAccept(c, mysql.TypeLonglong, uint64(math.MaxUint64), strvalue(uint64(math.MaxUint64)))
-	unsignedDeny(c, mysql.TypeLonglong, math.MaxUint64*1.1, strvalue(uint64(math.MaxUint64)))
+	unsignedDeny(c, mysql.TypeLonglong, math.MaxUint64*1.1, strvalue(uint64(math.MaxInt64)))
 
 	// integer from string
 	signedAccept(c, mysql.TypeLong, "	  234  ", "234")