fix: mismatch in column count and value count

go/vt/vtgate/planbuilder/operators/insert.go

@@ -417,6 +417,9 @@ func modifyForAutoinc(ins *sqlparser.Insert, vTable *vindexes.Table) (*Generate,
 	case sqlparser.Values:
 		autoIncValues := make(sqlparser.ValTuple, 0, len(rows))
 		for rowNum, row := range rows {
+			if len(ins.Columns) != len(row) {
+				return nil, vterrors.VT03006()
+			}
 			// Support the DEFAULT keyword by treating it as null
 			if _, ok := row[colNum].(*sqlparser.Default); ok {
 				row[colNum] = &sqlparser.NullVal{}

go/vt/vtgate/planbuilder/testdata/dml_cases.json

@@ -4889,5 +4889,49 @@
     "comment": "Unsupported update statement with a replica target destination",
     "query": "update `user[-]@replica`.user_metadata set id=2",
     "plan": "VT09002: update statement with a replica target"
+  },
+  {
+    "comment": "insert row values smaller than number of columns",
+    "query": "insert into unsharded(one, two, three, four) values (1, 2, 3)",
+    "plan": {
+      "QueryType": "INSERT",
+      "Original": "insert into unsharded(one, two, three, four) values (1, 2, 3)",
+      "Instructions": {
+        "OperatorType": "Insert",
+        "Variant": "Unsharded",
+        "Keyspace": {
+          "Name": "main",
+          "Sharded": false
+        },
+        "TargetTabletType": "PRIMARY",
+        "Query": "insert into unsharded(one, two, three, four) values (1, 2, 3)",
+        "TableName": "unsharded"
+      },
+      "TablesUsed": [
+        "main.unsharded"
+      ]
+    }
+  },
+  {
+    "comment": "insert row values greater than number of columns",
+    "query": "insert into unsharded(one, two, three) values (1, 2, 3, 4)",
+    "plan": {
+      "QueryType": "INSERT",
+      "Original": "insert into unsharded(one, two, three) values (1, 2, 3, 4)",
+      "Instructions": {
+        "OperatorType": "Insert",
+        "Variant": "Unsharded",
+        "Keyspace": {
+          "Name": "main",
+          "Sharded": false
+        },
+        "TargetTabletType": "PRIMARY",
+        "Query": "insert into unsharded(one, two, three) values (1, 2, 3, 4)",
+        "TableName": "unsharded"
+      },
+      "TablesUsed": [
+        "main.unsharded"
+      ]
+    }
   }
 ]