chore: import upstream snapshot with attribution

server/hook/table_add_column.go

@@ -0,0 +1,179 @@
+// Copyright 2026 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hook
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/cockroachdb/errors"
+	"github.com/dolthub/dolt/go/libraries/doltcore/doltdb"
+	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/plan"
+
+	"github.com/dolthub/doltgresql/core"
+	"github.com/dolthub/doltgresql/core/id"
+	pgtypes "github.com/dolthub/doltgresql/server/types"
+)
+
+// BeforeTableAddColumn handles validation that's unique to Doltgres.
+func BeforeTableAddColumn(ctx *sql.Context, runner sql.StatementRunner, nodeInterface sql.Node) (sql.Node, error) {
+	n, ok := nodeInterface.(*plan.AddColumn)
+	if !ok {
+		return nil, errors.Errorf("ADD COLUMN pre-hook expected `*plan.AddColumn` but received `%T`", nodeInterface)
+	}
+	// If the column being added doesn't have a default value, then we don't have anything to check (for now)
+	if n.Column().Default == nil {
+		return n, nil
+	}
+
+	// Grab the table being altered
+	doltTable := core.SQLNodeToDoltTable(n.Table)
+	if doltTable == nil {
+		// If this table isn't a Dolt table then we don't have anything to do
+		return n, nil
+	}
+	_, root, err := core.GetRootFromContext(ctx)
+	if err != nil {
+		return n, nil
+	}
+	tableName := doltTable.TableName()
+	tableAsType := id.NewType(tableName.Schema, tableName.Name)
+	allTableNames, err := root.GetAllTableNames(ctx, false)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, otherTableName := range allTableNames {
+		if doltdb.IsSystemTable(otherTableName) {
+			// System tables don't use any table types
+			continue
+		}
+		otherTable, ok, err := root.GetTable(ctx, otherTableName)
+		if err != nil {
+			return nil, err
+		}
+		if !ok {
+			return nil, errors.Errorf("root returned table name `%s` but it could not be found?", otherTableName.String())
+		}
+		otherTableSch, err := otherTable.GetSchema(ctx)
+		if err != nil {
+			return nil, err
+		}
+		for _, otherCol := range otherTableSch.GetAllCols().GetColumns() {
+			colType := otherCol.TypeInfo.ToSqlType()
+			dgtype, ok := colType.(*pgtypes.DoltgresType)
+			if !ok {
+				// If this isn't a Doltgres type, then it can't be a table type so we can ignore it
+				continue
+			}
+			if dgtype.ID != tableAsType {
+				// This column isn't our table type, so we can ignore it
+				continue
+			}
+			return nil, errors.Errorf(`cannot alter table "%s" because column "%s.%s" uses its row type`,
+				tableName.Name, otherTableName.Name, otherCol.Name)
+		}
+	}
+	return n, nil
+}
+
+// AfterTableAddColumn handles updating various table columns, alongside other validation that's unique to Doltgres.
+func AfterTableAddColumn(ctx *sql.Context, runner sql.StatementRunner, nodeInterface sql.Node) error {
+	n, ok := nodeInterface.(*plan.AddColumn)
+	if !ok {
+		return errors.Errorf("ADD COLUMN post-hook expected `*plan.AddColumn` but received `%T`", nodeInterface)
+	}
+
+	// Grab the table being altered
+	doltTable := core.SQLNodeToDoltTable(n.Table)
+	if doltTable == nil {
+		// If this table isn't a Dolt table then we don't have anything to do
+		return nil
+	}
+	_, root, err := core.GetRootFromContext(ctx)
+	if err != nil {
+		return err
+	}
+	tableName := doltTable.TableName()
+	tableAsType := id.NewType(tableName.Schema, tableName.Name)
+	allTableNames, err := root.GetAllTableNames(ctx, false)
+	if err != nil {
+		return err
+	}
+	sch := doltTable.Schema(ctx)
+
+	for _, otherTableName := range allTableNames {
+		if doltdb.IsSystemTable(otherTableName) {
+			// System tables don't use any table types
+			continue
+		}
+		otherTable, ok, err := root.GetTable(ctx, otherTableName)
+		if err != nil {
+			return err
+		}
+		if !ok {
+			return errors.Errorf("root returned table name `%s` but it could not be found?", otherTableName.String())
+		}
+		otherTableSch, err := otherTable.GetSchema(ctx)
+		if err != nil {
+			return err
+		}
+		for _, otherCol := range otherTableSch.GetAllCols().GetColumns() {
+			colType := otherCol.TypeInfo.ToSqlType()
+			dgtype, ok := colType.(*pgtypes.DoltgresType)
+			if !ok {
+				// If this isn't a Doltgres type, then it can't be a table type so we can ignore it
+				continue
+			}
+			if dgtype.ID != tableAsType {
+				// This column isn't our table type, so we can ignore it
+				continue
+			}
+			// Build the UPDATE statement that we'll run for this table
+			rowValues := make([]string, len(sch)+1)
+			for i, col := range sch {
+				rowValues[i] = fmt.Sprintf(`("%s")."%s"`, otherCol.Name, col.Name)
+			}
+			rowValues[len(rowValues)-1] = "NULL"
+			// The UPDATE changes the values in the table
+			updateStr := fmt.Sprintf(`UPDATE "%s"."%s" SET "%s" = ROW(%s)::"%s"."%s" WHERE length("%s"::text) > 0;`,
+				otherTableName.Schema, otherTableName.Name, otherCol.Name, strings.Join(rowValues, ","), tableName.Schema, tableName.Name, otherCol.Name)
+			// The ALTER updates the type on the schema since it still has the old one
+			alterStr := fmt.Sprintf(`ALTER TABLE "%s"."%s" ALTER COLUMN "%s" TYPE "%s"."%s";`,
+				otherTableName.Schema, otherTableName.Name, otherCol.Name, tableName.Schema, tableName.Name)
+			// We run the statements as though they were interpreted since we're running new statements inside the original
+			_, err = sql.RunInterpreted(ctx, func(subCtx *sql.Context) ([]sql.Row, error) {
+				_, rowIter, _, err := runner.QueryWithBindings(subCtx, updateStr, nil, nil, nil)
+				if err != nil {
+					return nil, err
+				}
+				_, err = sql.RowIterToRows(subCtx, rowIter)
+				if err != nil {
+					return nil, err
+				}
+				_, rowIter, _, err = runner.QueryWithBindings(subCtx, alterStr, nil, nil, nil)
+				if err != nil {
+					return nil, err
+				}
+				return sql.RowIterToRows(subCtx, rowIter)
+			})
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}