chore: import upstream snapshot with attribution

server/hook/delete_table.go

@@ -0,0 +1,157 @@
+// Copyright 2025 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 (
+	"github.com/cockroachdb/errors"
+	"github.com/dolthub/dolt/go/libraries/doltcore/doltdb"
+	"github.com/dolthub/dolt/go/libraries/doltcore/sqle"
+	"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/functions"
+	"github.com/dolthub/doltgresql/core/id"
+	"github.com/dolthub/doltgresql/core/procedures"
+	pgtypes "github.com/dolthub/doltgresql/server/types"
+)
+
+// BeforeTableDeletion performs all validation necessary to ensure that table deletion does not leave the database in an
+// invalid state.
+func BeforeTableDeletion(ctx *sql.Context, _ sql.StatementRunner, nodeInterface sql.Node) (sql.Node, error) {
+	// TODO: handle casts using a table name
+	n, ok := nodeInterface.(*plan.DropTable)
+	if !ok {
+		return nil, errors.Newf("DROP TABLE pre-hook expected `*plan.DropTable` but received `%T`", nodeInterface)
+	}
+	var resolvedTables []*sqle.DoltTable
+	var allTableNames []doltdb.TableName
+	for _, tbl := range n.Tables {
+		doltTable := core.SQLNodeToDoltTable(tbl)
+		if doltTable == nil {
+			// If this table isn't a Dolt table then we ignore it
+			continue
+		}
+		resolvedTables = append(resolvedTables, doltTable)
+		allTableNames = append(allTableNames, doltTable.TableName())
+	}
+	// TODO: handle DROP TABLE CASCADE
+	for _, doltTable := range resolvedTables {
+		// Check if the table is in a column
+		if err := beforeTableDeletionCheckTableColumns(ctx, doltTable, allTableNames); err != nil {
+			return nil, err
+		}
+		// Check if the table is in a function/procedure parameter
+		if err := beforeTableDeletionCheckFuncsProcs(ctx, doltTable, allTableNames); err != nil {
+			return nil, err
+		}
+	}
+	return n, nil
+}
+
+// beforeTableDeletionCheckTableColumns is called from BeforeTableDeletion and handles checking for columns that use a
+// table's type.
+func beforeTableDeletionCheckTableColumns(ctx *sql.Context, doltTable *sqle.DoltTable, allDeletedTables []doltdb.TableName) error {
+	tableName := doltTable.TableName()
+	_, root, err := core.GetRootFromContext(ctx)
+	if err != nil {
+		return err
+	}
+	tableAsType := id.NewType(tableName.Schema, tableName.Name)
+	allTableNames, err := root.GetAllTableNames(ctx, false)
+	if err != nil {
+		return err
+	}
+OuterLoop:
+	for _, otherTableName := range allTableNames {
+		if doltdb.IsSystemTable(otherTableName) {
+			// System tables don't use any table types
+			continue OuterLoop
+		}
+		for _, deletedTable := range allDeletedTables {
+			if deletedTable.EqualFold(otherTableName) {
+				// If we're also deleting this table, then it doesn't matter what the columns have
+				continue OuterLoop
+			}
+		}
+		otherTable, ok, err := root.GetTable(ctx, otherTableName)
+		if err != nil {
+			return err
+		}
+		if !ok {
+			return errors.Newf("root returned table name `%s` but it could not be found?", otherTableName.String())
+		}
+		otherTableSch, err := otherTable.GetSchema(ctx)
+		if err != nil {
+			return err
+		}
+		for _, col := range otherTableSch.GetAllCols().GetColumns() {
+			colType := col.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 {
+				// TODO: portion after newline should be in DETAILS but we don't yet support that in our error messages
+				return errors.Newf("cannot drop table %s because other objects depend on it\ncolumn %s of table %s depends on type %s",
+					tableName.Name, col.Name, otherTableName.Name, tableName.Name)
+			}
+		}
+	}
+	return nil
+}
+
+// beforeTableDeletionCheckFuncsProcs is called from BeforeTableDeletion and handles checking for function and procedure
+// parameters that use a table's type.
+func beforeTableDeletionCheckFuncsProcs(ctx *sql.Context, doltTable *sqle.DoltTable, allDeletedTables []doltdb.TableName) error {
+	tableName := doltTable.TableName()
+	tableAsType := id.NewType(tableName.Schema, tableName.Name)
+	funcsColl, err := core.GetFunctionsCollectionFromContext(ctx, "")
+	if err != nil {
+		return err
+	}
+	err = funcsColl.IterateFunctions(ctx, func(f functions.Function) (stop bool, err error) {
+		for _, paramType := range f.ParameterTypes {
+			if paramType == tableAsType {
+				// TODO: portion after newline should be in DETAILS but we don't yet support that in our error messages
+				return true, errors.Newf("cannot drop table %s because other objects depend on it\nfunction %s depends on type %s",
+					tableName.Name, f.Name().Name, tableName.Name)
+			}
+		}
+		return false, nil
+	})
+	if err != nil {
+		return err
+	}
+	procsColl, err := core.GetProceduresCollectionFromContext(ctx, "")
+	if err != nil {
+		return err
+	}
+	err = procsColl.IterateProcedures(ctx, func(p procedures.Procedure) (stop bool, err error) {
+		for _, paramType := range p.ParameterTypes {
+			if paramType == tableAsType {
+				// TODO: portion after newline should be in DETAILS but we don't yet support that in our error messages
+				return true, errors.Newf("cannot drop table %s because other objects depend on it\nfunction %s depends on type %s",
+					tableName.Name, p.Name().Name, tableName.Name)
+			}
+		}
+		return false, nil
+	})
+	if err != nil {
+		return err
+	}
+	return nil
+}