fix Expressions() of TableFunctionWrapper to make the function expression visible (#3226)

Author: jennifersp

sql/expression/tablefunction/table_function.go

@@ -68,7 +68,7 @@ func (t *TableFunctionWrapper) Expressions() []sql.Expression {
 	if t.funcExpr == nil {
 		return nil
 	}
-	return t.funcExpr.Children()
+	return []sql.Expression{t.funcExpr}
 }
 
 func (t *TableFunctionWrapper) IsReadOnly() bool {
@@ -130,15 +130,10 @@ func (t *TableFunctionWrapper) WithExpressions(exprs ...sql.Expression) (sql.Nod
 			return nil, sql.ErrInvalidChildrenNumber.New(t, len(exprs), 0)
 		}
 	}
-	l := len(t.funcExpr.Children())
-	if len(exprs) != l {
-		return nil, sql.ErrInvalidChildrenNumber.New(t, len(exprs), l)
+	if len(exprs) != 1 {
+		return nil, sql.ErrInvalidChildrenNumber.New(t, len(exprs), 1)
 	}
 	nt := *t
-	nf, err := nt.funcExpr.WithChildren(exprs...)
-	if err != nil {
-		return nil, err
-	}
-	nt.funcExpr = nf
+	nt.funcExpr = exprs[0]
 	return &nt, nil
 }

sql/plan/values.go

@@ -36,7 +36,7 @@ func NewValues(tuples [][]sql.Expression) *Values {
 	return &Values{ExpressionTuples: tuples}
 }
 
-// NewValuesWithAliasName creates a Values node with the given row and column aliases.
+// NewValuesWithAlias creates a Values node with the given row and column aliases.
 func NewValuesWithAlias(tableName string, columnNames map[string]string, tuples [][]sql.Expression) *Values {
 	return &Values{ExpressionTuples: tuples, AliasName: tableName, ColumnNames: columnNames}
 }

sql/rows.go

@@ -187,14 +187,47 @@ type sliceRowIter struct {
 	idx  int
 }
 
-func (i *sliceRowIter) Next(*Context) (Row, error) {
+func (i *sliceRowIter) Next(ctx *Context) (Row, error) {
 	if i.idx >= len(i.rows) {
 		return nil, io.EOF
 	}
 
-	r := i.rows[i.idx]
-	i.idx++
-	return r.Copy(), nil
+	vals, hasRowIter, rowIterEnded, err := unwrapRowIterAsReturnedResult(ctx, i.rows[i.idx])
+	if err != nil {
+		return nil, err
+	}
+
+	if !hasRowIter {
+		i.idx++
+	} else if rowIterEnded {
+		return nil, io.EOF
+	}
+
+	return NewRow(vals...), nil
+}
+
+// unwrapRowIterAsReturnedResult unwraps the row if there is any RowIter in the given Row
+// creating multiple Rows from a single Row.
+func unwrapRowIterAsReturnedResult(ctx *Context, r Row) ([]any, bool, bool, error) {
+	vals := make([]interface{}, len(r))
+	var hasActiveRowIter = false
+	var hasRowIter = false
+	for i, v := range r {
+		if ri, ok := v.(RowIter); ok {
+			hasRowIter = true
+			nv, err := ri.Next(ctx)
+			if err == nil {
+				hasActiveRowIter = true
+			}
+			if nv != nil && len(nv) > 0 {
+				// TODO: can set returning iter return multiple values in the row?
+				vals[i] = nv[0]
+			}
+		} else {
+			vals[i] = v
+		}
+	}
+	return vals, hasRowIter, !hasActiveRowIter && hasRowIter, nil
 }
 
 func (i *sliceRowIter) Close(*Context) error {