types: fix wrong truncated val for bit type (#25198)

pingcap · Jun 7, 2021 · 2017d2f · 2017d2f
1 parent 3947c5c
commit 2017d2f
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/expression/integration_test.go b/expression/integration_test.go
@@ -397,6 +397,15 @@ func (s *testIntegrationSuite) TestConvertToBit(c *C) {
 		"Warning 1690 constant 599999999 overflows tinyint",
 		"Warning 1406 Data Too Long, field len 63"))
 	tk.MustQuery("select * from t;").Check(testkit.Rows("127 \u007f\xff\xff\xff\xff\xff\xff\xff"))
+
+	// For issue 24900
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("create table t(b bit(16));")
+	tk.MustExec("insert ignore into t values(0x3635313836),(0x333830);")
+	tk.MustQuery("show warnings;").Check(testkit.Rows(
+		"Warning 1406 Data Too Long, field len 16",
+		"Warning 1406 Data Too Long, field len 16"))
+	tk.MustQuery("select * from t;").Check(testkit.Rows("\xff\xff", "\xff\xff"))
 }
 
 func (s *testIntegrationSuite2) TestMathBuiltin(c *C) {

diff --git a/types/datum.go b/types/datum.go
@@ -1478,7 +1478,7 @@ func (d *Datum) convertToMysqlBit(sc *stmtctx.StatementContext, target *FieldTyp
 		return Datum{}, errors.Trace(ErrDataTooLong.GenWithStack("Data Too Long, field len %d", target.Flen))
 	}
 	if target.Flen < 64 && uintValue >= 1<<(uint64(target.Flen)) {
-		uintValue &= (1 << (uint64(target.Flen))) - 1
+		uintValue = (1 << (uint64(target.Flen))) - 1
 		err = ErrDataTooLong.GenWithStack("Data Too Long, field len %d", target.Flen)
 	}
 	byteSize := (target.Flen + 7) >> 3