dolthub/dolt#9641 - Fix BIT Overflow

enginetest/queries/script_queries.go

@@ -120,6 +120,74 @@ type ScriptTestAssertion struct {
 // Unlike other engine tests, ScriptTests must be self-contained. No other tables are created outside the definition of
 // the tests.
 var ScriptTests = []ScriptTest{
+	{
+		// Regression test for https://github.com/dolthub/dolt/issues/9641
+		Name: "bit union max1err dolt#9641",
+		SetUpScript: []string{
+			"CREATE TABLE report_card (id INT PRIMARY KEY, archived BIT(1))",
+			"INSERT INTO report_card VALUES (1, 0)",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				// max1err
+				Query: `SELECT archived FROM report_card WHERE id = 1
+					UNION ALL  
+					SELECT 48 FROM report_card WHERE id = 1`,
+				Expected: []sql.Row{{int64(0)}, {int64(48)}},
+			},
+		},
+	},
+	{
+		// Regression test for https://github.com/dolthub/dolt/issues/9641
+		Name:    "bit union comprehensive regression test dolt#9641",
+		Dialect: "mysql",
+		SetUpScript: []string{
+			`CREATE TABLE t1 (
+				id int PRIMARY KEY,
+				name varchar(254),
+				archived bit(1) NOT NULL DEFAULT b'0',
+				archived_directly bit(1) NOT NULL DEFAULT b'0'
+			)`,
+			`CREATE TABLE t2 (
+				id int PRIMARY KEY,
+				name varchar(254),
+				archived bit(1) NOT NULL DEFAULT b'0'
+			)`,
+			"INSERT INTO t1 VALUES (1, 'Card1', b'0', b'0')",
+			"INSERT INTO t2 VALUES (2, 'Collection1', b'0')",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query: `SELECT *,
+					COUNT(*) OVER () AS total_count
+				FROM (
+					SELECT
+						5 AS model_ranking,
+						id,
+						name,
+						archived,
+						archived_directly
+					FROM t1
+					WHERE archived_directly = FALSE
+
+					UNION ALL
+
+					SELECT
+						7 AS model_ranking,
+						id,
+						name,
+						archived,
+						NULL AS archived_directly
+					FROM t2
+					WHERE archived = FALSE AND id <> 1
+				) AS dummy_alias`,
+				Expected: []sql.Row{
+					{int64(5), int64(1), "Card1", int64(0), int64(0), int64(2)},
+					{int64(7), int64(2), "Collection1", int64(0), nil, int64(2)},
+				},
+			},
+		},
+	},
 	{
 		Name: "outer join finish unmatched right side",
 		SetUpScript: []string{

sql/analyzer/resolve_unions.go

@@ -99,6 +99,10 @@ func finalizeUnions(ctx *sql.Context, a *Analyzer, n sql.Node, scope *plan.Scope
 		if err != nil {
 			return nil, transform.SameTree, err
 		}
+
+		// UNION can return multiple rows even when child queries use LIMIT 1, so disable Max1Row optimization
+		qFlags.Unset(sql.QFlagMax1Row)
+
 		return newN, transform.NewTree, nil
 	})
 }

sql/expression/convert.go

@@ -123,6 +123,9 @@ func GetConvertToType(l, r sql.Type) string {
 	if types.IsDecimal(l) || types.IsDecimal(r) {
 		return ConvertToDecimal
 	}
+	if types.IsBit(l) || types.IsBit(r) {
+		return ConvertToSigned
+	}
 	if types.IsUnsigned(l) && types.IsUnsigned(r) {
 		return ConvertToUnsigned
 	}

sql/iters/rel_iters.go

@@ -601,8 +601,9 @@ func (di *distinctIter) Dispose() {
 }
 
 type UnionIter struct {
-	Cur      sql.RowIter
-	NextIter func(ctx *sql.Context) (sql.RowIter, error)
+	Cur          sql.RowIter
+	NextIter     func(ctx *sql.Context) (sql.RowIter, error)
+	ResultSchema sql.Schema
 }
 
 func (ui *UnionIter) Next(ctx *sql.Context) (sql.Row, error) {
@@ -620,8 +621,23 @@ func (ui *UnionIter) Next(ctx *sql.Context) (sql.Row, error) {
 		if err != nil {
 			return nil, err
 		}
-		return ui.Cur.Next(ctx)
+		res, err = ui.Cur.Next(ctx)
+		if err != nil {
+			return nil, err
+		}
 	}
+
+	// Convert BIT values to Int64 when schema generalization changed types for server engine compatibility
+	if ui.ResultSchema != nil {
+		for i, val := range res {
+			if i < len(ui.ResultSchema) && val != nil {
+				if converted, _, err := ui.ResultSchema[i].Type.Convert(ctx, val); err == nil {
+					res[i] = converted
+				}
+			}
+		}
+	}
+
 	return res, err
 }
 

sql/plan/set_op.go

@@ -19,6 +19,7 @@ import (
 	"strings"
 
 	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/types"
 )
 
 const (
@@ -100,6 +101,7 @@ func (s *SetOp) Schema() sql.Schema {
 	for i := range ls {
 		c := *ls[i]
 		if i < len(rs) {
+			c.Type = types.GeneralizeTypes(ls[i].Type, rs[i].Type)
 			c.Nullable = ls[i].Nullable || rs[i].Nullable
 		}
 		ret[i] = &c

sql/rowexec/rel.go

@@ -813,6 +813,7 @@ func (b *BaseBuilder) buildSetOp(ctx *sql.Context, s *plan.SetOp, row sql.Row) (
 			NextIter: func(ctx *sql.Context) (sql.RowIter, error) {
 				return b.buildNodeExec(ctx, s.Right(), row)
 			},
+			ResultSchema: s.Schema(),
 		}
 	case plan.IntersectType:
 		var iter2 sql.RowIter

sql/types/bit.go

@@ -193,6 +193,11 @@ func (t BitType_) SQL(ctx *sql.Context, dest []byte, v interface{}) (sqltypes.Va
 	if v == nil {
 		return sqltypes.NULL, nil
 	}
+
+	// Delegate int64 values to Int64.SQL to prevent server engine []uint8 serialization errors
+	if int64Val, ok := v.(int64); ok {
+		return Int64.SQL(ctx, dest, int64Val)
+	}
 	value, _, err := t.Convert(ctx, v)
 	if err != nil {
 		return sqltypes.Value{}, err

sql/types/conversion.go

@@ -637,6 +637,11 @@ func generalizeNumberTypes(a, b sql.Type) sql.Type {
 // TODO: Create and handle "Illegal mix of collations" error
 // TODO: Handle extended types, like DoltgresType
 func GeneralizeTypes(a, b sql.Type) sql.Type {
+	// BIT types must convert to Int64 in UNION to avoid server engine serialization errors with []uint8
+	if (IsBit(a) || IsBit(b)) && (IsBit(a) && IsBit(b) || IsNullType(a) || IsNullType(b)) {
+		return Int64
+	}
+
 	if reflect.DeepEqual(a, b) {
 		return a
 	}
@@ -693,19 +698,6 @@ func GeneralizeTypes(a, b sql.Type) sql.Type {
 		return LongBlob
 	}
 
-	aIsBit := IsBit(a)
-	bIsBit := IsBit(b)
-	if aIsBit && bIsBit {
-		// TODO: match max bits to max of max bits between a and b
-		return a.Promote()
-	}
-	if aIsBit {
-		a = Int64
-	}
-	if bIsBit {
-		b = Int64
-	}
-
 	aIsYear := IsYear(a)
 	bIsYear := IsYear(b)
 	if aIsYear && bIsYear {