Implement config validation to find unused keys (#665)

Summary:
Pull Request resolved: #665

Implement a `ClassyConfigDict` type which supports tracking reads and freezing the map (the latter is unused currently).

Added it to `build_task` to catch cases where we don't use any keys passed by users.

This will not catch all instances, like when some components do a deepcopy - we assume all the keys and sub-keys are read in such a situation

Differential Revision: D25321360

fbshipit-source-id: ff71e61298baa6c30d0e4719ec5512a20fda955c

Author: mannatsingh

classy_vision/configuration/__init__.py

@@ -0,0 +1,9 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from .classy_config_dict import ClassyConfigDict
+from .config_error import ConfigError, ConfigUnusedKeysError
+
+__all__ = ["ClassyConfigDict", "ConfigError", "ConfigUnusedKeysError"]

classy_vision/configuration/classy_config_dict.py

@@ -0,0 +1,194 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import copy
+import json
+from collections.abc import MutableMapping, Mapping
+
+from .config_error import ConfigUnusedKeysError
+
+
+class ClassyConfigDict(MutableMapping):
+    """Mapping which can be made immutable. Also supports tracking unused keys."""
+
+    def __init__(self, *args, **kwargs):
+        """Create a ClassyConfigDict.
+
+        Supports the same API as a dict and recursively converts all dicts to
+        ClassyConfigDicts.
+        """
+
+        # NOTE: Another way to implement this would be to subclass dict, but since dict
+        # is a built-in, it isn't treated like a regular MutableMapping, and calls like
+        # func(**map) are handled mysteriously, probably interpreter dependent.
+        # The downside with this implementation is that this isn't a full dict and is
+        # just a mapping, which means some features like JSON serialization don't work
+
+        self._dict = dict(*args, **kwargs)
+        self._frozen = False
+        self._keys_read = set()
+        for k, v in self._dict.items():
+            self._dict[k] = self._from_dict(v)
+
+    @classmethod
+    def _from_dict(cls, obj):
+        """Recursively convert all dicts inside obj to ClassyConfigDicts"""
+
+        if isinstance(obj, Mapping):
+            obj = ClassyConfigDict({k: cls._from_dict(v) for k, v in obj.items()})
+        elif isinstance(obj, (list, tuple)):
+            # tuples are also converted to lists
+            obj = [cls._from_dict(v) for v in obj]
+        return obj
+
+    def to_dict(self):
+        """Return a vanilla Python dict, converting dicts recursively"""
+        return self._to_dict(self)
+
+    @classmethod
+    def _to_dict(cls, obj):
+        """Recursively convert obj to vanilla Python dicts"""
+        if isinstance(obj, ClassyConfigDict):
+            obj = {k: cls._to_dict(v) for k, v in obj.items()}
+        elif isinstance(obj, (list, tuple)):
+            # tuples are also converted to lists
+            obj = [cls._to_dict(v) for v in obj]
+        return obj
+
+    def keys(self):
+        return self._dict.keys()
+
+    def items(self):
+        self._keys_read.update(self._dict.keys())
+        return self._dict.items()
+
+    def values(self):
+        self._keys_read.update(self._dict.keys())
+        return self._dict.values()
+
+    def pop(self, key, default=None):
+        return self._dict.pop(key, default)
+
+    def popitem(self):
+        return self._dict.popitem()
+
+    def clear(self):
+        self._dict.clear()
+
+    def update(self, *args, **kwargs):
+        if self._frozen:
+            raise TypeError("Frozen ClassyConfigDicts do not support updates")
+        self._dict.update(*args, **kwargs)
+
+    def setdefault(self, key, default=None):
+        return self._dict.setdefault(key, default)
+
+    def __contains__(self, key):
+        return key in self._dict
+
+    def __eq__(self, obj):
+        return self._dict == obj
+
+    def __len__(self):
+        return len(self._dict)
+
+    def __getitem__(self, key):
+        self._keys_read.add(key)
+        return self._dict.__getitem__(key)
+
+    def __iter__(self):
+        return iter(self._dict)
+
+    def __str__(self):
+        return json.dumps(self.to_dict(), indent=4)
+
+    def __repr__(self):
+        return repr(self._dict)
+
+    def get(self, key, default=None):
+        if key in self._dict.keys():
+            self._keys_read.add(key)
+        return self._dict.get(key, default)
+
+    def __copy__(self):
+        ret = ClassyConfigDict()
+        for key, value in self._dict.items():
+            self._keys_read.add(key)
+            ret._dict[key] = value
+
+    def copy(self):
+        return self.__copy__()
+
+    def __deepcopy__(self, memo=None):
+        # for deepcopies we mark all the keys and sub-keys as read
+        ret = ClassyConfigDict()
+        for key, value in self._dict.items():
+            self._keys_read.add(key)
+            ret._dict[key] = copy.deepcopy(value)
+        return ret
+
+    def __setitem__(self, key, value):
+        if self._frozen:
+            raise TypeError("Frozen ClassyConfigDicts do not support assignment")
+        if isinstance(value, dict) and not isinstance(value, ClassyConfigDict):
+            value = ClassyConfigDict(value)
+        self._dict.__setitem__(key, value)
+
+    def __delitem__(self, key):
+        if self._frozen:
+            raise TypeError("Frozen ClassyConfigDicts do not support key deletion")
+        del self._dict[key]
+
+    def _freeze(self, obj):
+        if isinstance(obj, Mapping):
+            assert isinstance(obj, ClassyConfigDict), f"{obj} is not a ClassyConfigDict"
+            obj._frozen = True
+            for value in obj.values():
+                self._freeze(value)
+        elif isinstance(obj, list):
+            for value in obj:
+                self._freeze(value)
+
+    def _reset_tracking(self, obj):
+        if isinstance(obj, Mapping):
+            assert isinstance(obj, ClassyConfigDict), f"{obj} is not a ClassyConfigDict"
+            obj._keys_read = set()
+            for value in obj._dict.values():
+                self._reset_tracking(value)
+        elif isinstance(obj, list):
+            for value in obj:
+                self._reset_tracking(value)
+
+    def _unused_keys(self, obj):
+        unused_keys = []
+        if isinstance(obj, Mapping):
+            assert isinstance(obj, ClassyConfigDict), f"{obj} is not a ClassyConfigDict"
+            unused_keys = [key for key in obj._dict.keys() if key not in obj._keys_read]
+            for key, value in obj._dict.items():
+                unused_keys += [
+                    f"{key}.{subkey}" for subkey in self._unused_keys(value)
+                ]
+        elif isinstance(obj, list):
+            for i, value in enumerate(obj):
+                unused_keys += [f"{i}.{subkey}" for subkey in self._unused_keys(value)]
+        return unused_keys
+
+    def freeze(self):
+        """Freeze the ClassyConfigDict to disallow mutations"""
+        self._freeze(self)
+
+    def reset_tracking(self):
+        """Reset key tracking"""
+        self._reset_tracking(self)
+
+    def unused_keys(self):
+        """Fetch all the unused keys"""
+        return self._unused_keys(self)
+
+    def check_unused_keys(self):
+        """Raise if the config has unused keys"""
+        unused_keys = self.unused_keys()
+        if unused_keys:
+            raise ConfigUnusedKeysError(unused_keys)

classy_vision/configuration/config_error.py

@@ -0,0 +1,16 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from typing import List
+
+
+class ConfigError(Exception):
+    pass
+
+
+class ConfigUnusedKeysError(ConfigError):
+    def __init__(self, unused_keys: List[str]):
+        self.unused_keys = unused_keys
+        super().__init__(f"The following keys were unused: {self.unused_keys}")

classy_vision/optim/sgd.py

@@ -7,6 +7,7 @@
 from typing import Any, Dict
 
 import torch.optim
+from classy_vision.configuration import ClassyConfigDict
 
 from . import ClassyOptimizer, register_optimizer
 
@@ -63,10 +64,11 @@ def from_config(cls, config: Dict[str, Any]) -> "SGD":
         config.setdefault("weight_decay", 0.0)
         config.setdefault("nesterov", False)
         config.setdefault("use_larc", False)
-        config.setdefault(
-            "larc_config", {"clip": True, "eps": 1e-08, "trust_coefficient": 0.02}
-        )
-
+        if config["use_larc"]:
+            larc_config = ClassyConfigDict(clip=True, eps=1e-8, trust_coefficient=0.02)
+        else:
+            larc_config = None
+        config.setdefault("larc_config", larc_config)
         assert (
             config["momentum"] >= 0.0
             and config["momentum"] < 1.0

classy_vision/tasks/__init__.py

@@ -6,11 +6,11 @@
 
 from pathlib import Path
 
+from classy_vision.configuration import ClassyConfigDict
 from classy_vision.generic.registry_utils import import_all_modules
 
 from .classy_task import ClassyTask
 
-
 FILE_ROOT = Path(__file__).parent
 
 
@@ -26,8 +26,13 @@ def build_task(config):
     "foo": "bar"}` will find a class that was registered as "my_task"
     (see :func:`register_task`) and call .from_config on it."""
 
+    config = ClassyConfigDict(config)
+
     task = TASK_REGISTRY[config["name"]].from_config(config)
 
+    # at this stage all the configs keys should have been used
+    config.check_unused_keys()
+
     return task
 
 

classy_vision/tasks/classification_task.py

@@ -494,6 +494,7 @@ def from_config(cls, config: Dict[str, Any]) -> "ClassificationTask":
         Returns:
             A ClassificationTask instance.
         """
+
         test_only = config.get("test_only", False)
         if not test_only:
             # TODO Make distinction between epochs and phases in optimizer clear
@@ -1252,7 +1253,6 @@ def log_phase_end(self, tag):
 
     def __repr__(self):
         if hasattr(self, "_config"):
-            config = json.dumps(self._config, indent=4)
-            return f"{super().__repr__()} initialized with config:\n{config}"
+            return f"{super().__repr__()} initialized with config:\n{self._config}"
 
         return super().__repr__()