Fix DEFAULT insert for NULL or unspecified column default values (#…

…965)

server/analyzer/assign_insert_casts.go

@@ -23,6 +23,7 @@ import (
 	"github.com/dolthub/go-mysql-server/sql/expression"
 	"github.com/dolthub/go-mysql-server/sql/plan"
 	"github.com/dolthub/go-mysql-server/sql/transform"
+	"github.com/dolthub/go-mysql-server/sql/types"
 
 	pgexprs "github.com/dolthub/doltgresql/server/expression"
 	pgtypes "github.com/dolthub/doltgresql/server/types"
@@ -60,7 +61,12 @@ func AssignInsertCasts(ctx *sql.Context, a *analyzer.Analyzer, node sql.Node, sc
 		for rowIndex, rowExprs := range values.ExpressionTuples {
 			newValues[rowIndex] = make([]sql.Expression, len(rowExprs))
 			for columnIndex, colExpr := range rowExprs {
-				fromColType, ok := colExpr.Type().(pgtypes.DoltgresType)
+				// Null ColumnDefaultValues or empty DefaultValues are not properly typed in TypeSanitizer, so we must handle them here
+				colExprType := colExpr.Type()
+				if colExprType == nil || colExprType == types.Null {
+					colExprType = pgtypes.UnknownType{}
+				}
+				fromColType, ok := colExprType.(pgtypes.DoltgresType)
 				if !ok {
 					return nil, transform.NewTree, fmt.Errorf("INSERT: non-Doltgres type found in values source: %s", fromColType.String())
 				}

testing/go/insert_test.go

@@ -132,5 +132,23 @@ func TestInsert(t *testing.T) {
 				},
 			},
 		},
+		{
+			Name: "null and unspecified default values",
+			SetUpScript: []string{
+				"CREATE TABLE t (i INT DEFAULT NULL, j INT)",
+			},
+			Assertions: []ScriptTestAssertion{
+				{
+					Query:            "INSERT INTO t VALUES (default, default)",
+					SkipResultsCheck: true,
+				},
+				{
+					Query: "SELECT * FROM t",
+					Expected: []sql.Row{
+						{nil, nil},
+					},
+				},
+			},
+		},
 	})
 }