python: replace Ddl.read_ddl_file(path) with Ddl.read_ddl(doc)

include/gemmi/ddl.hpp

@@ -37,6 +37,7 @@ struct GEMMI_DLL Ddl {
   Ddl(Ddl const&) = delete;
   Ddl& operator=(Ddl const&) = delete;
 
+  /// it moves doc to ddl_docs_ to control lifetime and prevent modifications
   void read_ddl(cif::Document&& doc);
 
   bool validate_cif(const cif::Document& doc) const;

python/cif.cpp

@@ -462,9 +462,10 @@ void add_cif(nb::module_& cif) {
        nb::arg("use_context")=true, nb::arg("use_linked_groups")=true,
        nb::arg("use_mandatory")=true, nb::arg("use_unique_keys")=true)
     .def("set_logger", [](Ddl& self, gemmi::Logger&& logger) { self.logger = std::move(logger); })
-    .def("read_ddl_file", [](Ddl& self, const std::string& path) {
-        self.read_ddl(gemmi::read_cif_gz(path));
-    }, nb::arg("path"))
+    .def("read_ddl", [](Ddl& self, Document& doc) {
+        self.read_ddl(std::move(doc));
+        doc.clear();
+    }, nb::arg("doc"))
     .def("validate_cif", &Ddl::validate_cif)
     ;
 }

tests/test_cif.py

@@ -390,9 +390,11 @@ def test_validation(self):
         """)
         msg_list = []
         ddl = cif.Ddl(logger=(lambda msg: msg_list.append(msg), 6))
-        ddl.read_ddl_file(full_path('mmcif_pdbx_v50_frag.dic'))
-        self.assertTrue(len(msg_list) == 1)
-        self.assertTrue(msg_list[0].startswith("Bad DDL2: can't parse regex"))
+        ddl.read_ddl(cif.read(full_path('mmcif_pdbx_v50_frag.dic')))
+        if msg_list:
+            # regex for type binary may result in regex_error
+            self.assertEqual(len(msg_list), 1)
+            self.assertTrue(msg_list[0].startswith("Bad DDL2: can't parse regex"))
         msg_list = []
         ddl.validate_cif(doc)
         self.assertEqual(msg_list,