[Fix] Support Runner dump cfg without filename (#228)

* fix runner dump cfg

* convert dict cfg to Config

mmengine/runner/runner.py

@@ -198,7 +198,7 @@ class Runner:
         >>> runner.train()
         >>> runner.test()
     """
-    cfg: ConfigType
+    cfg: Config
     train_loop: Optional[Union[BaseLoop, Dict]]
     val_loop: Optional[Union[BaseLoop, Dict]]
     test_loop: Optional[Union[BaseLoop, Dict]]
@@ -237,9 +237,12 @@ class Runner:
         # recursively copy the `cfg` because `self.cfg` will be modified
         # everywhere.
         if cfg is not None:
-            self.cfg = copy.deepcopy(cfg)
+            if isinstance(cfg, Config):
+                self.cfg = copy.deepcopy(cfg)
+            elif isinstance(cfg, dict):
+                self.cfg = Config(cfg)
         else:
-            self.cfg = dict()
+            self.cfg = Config(dict())
 
         self._epoch = 0
         self._iter = 0
@@ -313,9 +316,8 @@ class Runner:
 
         if experiment_name is not None:
             self._experiment_name = f'{experiment_name}_{self._timestamp}'
-        elif self.cfg.get('filename') is not None:
-            filename_no_ext = osp.splitext(osp.basename(
-                self.cfg['filename']))[0]
+        elif self.cfg.filename is not None:
+            filename_no_ext = osp.splitext(osp.basename(self.cfg.filename))[0]
             self._experiment_name = f'{filename_no_ext}_{self._timestamp}'
         else:
             self._experiment_name = self.timestamp
@@ -1596,10 +1598,8 @@ class Runner:
     @master_only
     def dump_config(self) -> None:
         """Dump config to `work_dir`."""
-        if isinstance(self.cfg,
-                      Config) and self.cfg.get('filename') is not None:
-            self.cfg.dump(
-                osp.join(self.work_dir, osp.basename(self.cfg.filename)))
-        elif self.cfg:
-            # TODO
-            pass
+        if self.cfg.filename is not None:
+            filename = osp.basename(self.cfg.filename)
+        else:
+            filename = f'{self.timestamp}.py'
+        self.cfg.dump(osp.join(self.work_dir, filename))

tests/test_runner/test_runner.py

@@ -398,8 +398,26 @@ class TestRunner(TestCase):
         runner.train()
         runner.test()
 
-        # 5. test `dump_config`
-        # TODO
+    def test_dump_config(self):
+        # dump config from dict.
+        cfg = copy.deepcopy(self.epoch_based_cfg)
+        for idx, cfg in enumerate((cfg, cfg._cfg_dict)):
+            cfg.experiment_name = f'test_dump{idx}'
+            runner = Runner.from_cfg(cfg=cfg)
+            assert osp.exists(
+                osp.join(runner.work_dir, f'{runner.timestamp}.py'))
+            # dump config from file.
+            with tempfile.TemporaryDirectory() as temp_config_dir:
+                temp_config_file = tempfile.NamedTemporaryFile(
+                    dir=temp_config_dir, suffix='.py')
+                file_cfg = Config(
+                    self.epoch_based_cfg._cfg_dict,
+                    filename=temp_config_file.name)
+                file_cfg.experiment_name = f'test_dump2{idx}'
+                runner = Runner.from_cfg(cfg=file_cfg)
+                assert osp.exists(
+                    osp.join(runner.work_dir,
+                             osp.basename(temp_config_file.name)))
 
     def test_from_cfg(self):
         runner = Runner.from_cfg(cfg=self.epoch_based_cfg)