fix the issue that the default value for BIT is wrong

Signed-off-by: Yang Keao <yangkeao@chunibyo.icu>
pingcap · Nov 11, 2024 · 5d0e1cd · 5d0e1cd
1 parent 6528da5
commit 5d0e1cd
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Showing 6 changed files with 55 additions and 0 deletions.
diff --git a/pkg/ddl/add_column.go b/pkg/ddl/add_column.go
@@ -1225,6 +1225,21 @@ func checkColumnDefaultValue(ctx exprctx.BuildContext, col *table.Column, value
 			}
 		}
 	}
+	if value != nil && col.GetType() == mysql.TypeBit {
+		v, ok := value.(string)
+		if !ok {
+			return hasDefaultValue, value, types.ErrInvalidDefault.GenWithStackByArgs(col.Name.O)
+		}
+
+		// FIXME: the length of the original bit literal has been lost and it'll be ceiled to bytes.
+		// For example, the following DDL will be allowed, because 4 = 32 / 8.
+		// CREATE TABLE t (a bit(25) default b'111111111111111111111111111111');
+		//
+		// The `Flen` is ceiled to make sure the DDL allowed in MySQL is also allowed in TiDB.
+		if (col.GetFlen()+7)/8 < len(v) {
+			return hasDefaultValue, value, types.ErrInvalidDefault.GenWithStackByArgs(col.Name.O)
+		}
+	}
 	return hasDefaultValue, value, nil
 }
 

diff --git a/pkg/table/column.go b/pkg/table/column.go
@@ -614,6 +614,12 @@ func getColDefaultValue(ctx expression.BuildContext, col *model.ColumnInfo, defa
 
 	switch col.GetType() {
 	case mysql.TypeTimestamp, mysql.TypeDate, mysql.TypeDatetime:
+	case mysql.TypeBit:
+		defaultValBytes, ok := defaultVal.(string)
+		intest.Assert(ok, "the default value type for bit should be string")
+		if ok {
+			return types.NewBinaryLiteralDatum(types.BinaryLiteral(defaultValBytes)), nil
+		}
 	default:
 		value, err := CastColumnValue(ctx, types.NewDatum(defaultVal), col, false, false)
 		if err != nil {

diff --git a/tests/integrationtest/r/ddl/column.result b/tests/integrationtest/r/ddl/column.result
@@ -84,3 +84,13 @@ t	CREATE TABLE `t` (
   `a` decimal(10,0) DEFAULT NULL,
   `b` decimal(10,0) DEFAULT NULL
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin
+drop table if exists t;
+create table t(a bit(2) default b'1111111111111111111111111111111');
+Error 1067 (42000): Invalid default value for 'a'
+create table t(a bit(4) default b'1111111111111111111111111111111');
+Error 1067 (42000): Invalid default value for 'a'
+create table t(a bit(24) default b'111111111111111111111111111111');
+Error 1067 (42000): Invalid default value for 'a'
+create table t(a bit(25) default b'111111111111111111111111111111'); -- fix me. TiDB cannot know the accurate bit literal length after parser, so the 25 bits limitation are ceiled to 32.
+drop table t;
+create table t(a bit(32) default b'1111111111111111111111111111111');
diff --git a/tests/integrationtest/r/table/tables.result b/tests/integrationtest/r/table/tables.result
@@ -24,3 +24,9 @@ select count(distinct(_tidb_rowid>>48)) from shard_t;
 count(distinct(_tidb_rowid>>48))
 3
 set @@tidb_shard_allocate_step=default;
+drop table if exists t;
+create table t(a bit(32) default b'1100010001001110011000100100111');
+insert into t values ();
+select hex(a) from t;
+hex(a)
+62273127
diff --git a/tests/integrationtest/t/ddl/column.test b/tests/integrationtest/t/ddl/column.test
@@ -44,3 +44,15 @@ alter table t1 add column d date default '2024-10';
 drop table if exists t;
 create table t(a decimal(0,0), b decimal(0));
 show create table t;
+
+# TestTooLongDefaultValueForBit
+drop table if exists t;
+-- error 1067
+create table t(a bit(2) default b'1111111111111111111111111111111');
+-- error 1067
+create table t(a bit(4) default b'1111111111111111111111111111111');
+-- error 1067
+create table t(a bit(24) default b'111111111111111111111111111111');
+create table t(a bit(25) default b'111111111111111111111111111111'); -- fix me. TiDB cannot know the accurate bit literal length after parser, so the 25 bits limitation are ceiled to 32.
+drop table t;
+create table t(a bit(32) default b'1111111111111111111111111111111');
diff --git a/tests/integrationtest/t/table/tables.test b/tests/integrationtest/t/table/tables.test
@@ -22,3 +22,9 @@ insert into shard_t values (12);
 select count(distinct(_tidb_rowid>>48)) from shard_t;
 
 set @@tidb_shard_allocate_step=default;
+
+# TestInsertBitDefaultValue
+drop table if exists t;
+create table t(a bit(32) default b'1100010001001110011000100100111');
+insert into t values ();
+select hex(a) from t;