amend overflow fix

Author: elianddb

enginetest/queries/script_queries.go

@@ -120,6 +120,24 @@ 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 regression test dolt#9641",
+		SetUpScript: []string{
+			"CREATE TABLE bit_union_test_9641 (id INT PRIMARY KEY, flag BIT(1))",
+			"INSERT INTO bit_union_test_9641 VALUES (1, 0), (2, 1)",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query:    "SELECT flag FROM bit_union_test_9641 WHERE id = 1 UNION SELECT NULL as flag",
+				Expected: []sql.Row{{int64(0)}, {nil}},
+			},
+			{
+				Query:    "SELECT flag FROM bit_union_test_9641 WHERE id = 1 UNION SELECT 48 as flag",
+				Expected: []sql.Row{{int64(0)}, {int64(48)}},
+			},
+		},
+	},
 	{
 		Name: "outer join finish unmatched right side",
 		SetUpScript: []string{

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/dolthub/go-icu-regex v0.0.0-20250327004329-6799764f2dad
 	github.com/dolthub/jsonpath v0.0.2-0.20240227200619-19675ab05c71
 	github.com/dolthub/sqllogictest/go v0.0.0-20201107003712-816f3ae12d81
-	github.com/dolthub/vitess v0.0.0-20250813175212-45844169a751
+	github.com/dolthub/vitess v0.0.0-20250730174048-497aebb8cea7
 	github.com/go-sql-driver/mysql v1.7.2-0.20231213112541-0004702b931d
 	github.com/gocraft/dbr/v2 v2.7.2
 	github.com/google/uuid v1.3.0

go.sum

@@ -20,8 +20,6 @@ github.com/dolthub/sqllogictest/go v0.0.0-20201107003712-816f3ae12d81 h1:7/v8q9X
 github.com/dolthub/sqllogictest/go v0.0.0-20201107003712-816f3ae12d81/go.mod h1:siLfyv2c92W1eN/R4QqG/+RjjX5W2+gCTRjZxBjI3TY=
 github.com/dolthub/vitess v0.0.0-20250730174048-497aebb8cea7 h1:l+mWO0xoh4eG1J9gMS87opL6N6WGAQitF36R/Lg4bWs=
 github.com/dolthub/vitess v0.0.0-20250730174048-497aebb8cea7/go.mod h1:1gQZs/byeHLMSul3Lvl3MzioMtOW1je79QYGyi2fd70=
-github.com/dolthub/vitess v0.0.0-20250813175212-45844169a751 h1:BBQKyvyODewdQxS+ICklMn1d/fFj2pVlkmMN1QFY4ms=
-github.com/dolthub/vitess v0.0.0-20250813175212-45844169a751/go.mod h1:1gQZs/byeHLMSul3Lvl3MzioMtOW1je79QYGyi2fd70=
 github.com/go-sql-driver/mysql v1.4.1/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=

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 operations can return multiple rows, so Max1Row optimization is invalid
+		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
 	}
@@ -693,18 +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)