Merge pull request #104 from jacebrowning/strict-option

Disable attribute inference by default

CHANGES.md

@@ -5,6 +5,7 @@
 - Added preliminary support for JSON serialization (@pr0xmeh).
 - Renamed `yorm.converters` to `yorm.types`.
 - Now maintaining the signature on mapped objects.
+- Disabled attribute inference unless `strict=False`.
 
 ## 0.5 (2015/09/25)
 

tests/test_examples.py

@@ -115,7 +115,7 @@ def __repr__(self):
         return "<auto off {}>".format(id(self))
 
 
-@yorm.sync("sample.yml")
+@yorm.sync("sample.yml", strict=False)
 class SampleEmptyDecorated:
     """Sample class using standard attribute types."""
 
@@ -348,7 +348,7 @@ def test_nesting(self, tmpdir):
         _sample = SampleNested()
         attrs = {'count': Integer,
                  'results': StatusDictionaryList}
-        sample = yorm.sync(_sample, "sample.yml", attrs)
+        sample = yorm.sync(_sample, "sample.yml", attrs, strict=False)
 
         # check defaults
         assert 0 == sample.count

tests/test_imports.py

@@ -15,7 +15,7 @@ def test_from_top_constants():
 
 def test_from_top_clases():
     from yorm import Mappable  # base class for mapped objects
-    from yorm import Converter, Convertible  # base class for types
+    from yorm import Converter, Container  # base class for types
 
 
 def test_from_top_decorators():

yorm/__init__.py

@@ -3,7 +3,7 @@
 import sys
 
 __project__ = 'YORM'
-__version__ = '0.6.dev5'
+__version__ = '0.6.dev7'
 
 VERSION = __project__ + '-' + __version__
 

yorm/bases/__init__.py

@@ -1,6 +1,4 @@
 """Base classes for mapping and conversion."""
 
-from .container import Container
-from .converter import Converter
 from .mappable import Mappable
-from .convertible import Convertible
+from .converter import Converter, Container

yorm/bases/converter.py

@@ -1,27 +1,51 @@
-"""Base classes for converters."""
+"""Converter classes."""
 
-import abc
+from abc import ABCMeta, abstractclassmethod, abstractmethod
 
 from .. import common
+from . import Mappable
 
 
 log = common.logger(__name__)
 
 
-class Converter(metaclass=abc.ABCMeta):
-    """Base class for immutable attribute converters."""
+class Converter(metaclass=ABCMeta):
+    """Base class for attribute converters."""
 
-    @abc.abstractclassmethod
+    @abstractclassmethod
     def create_default(cls):
         """Create a default value for an attribute."""
         raise NotImplementedError(common.OVERRIDE_MESSAGE)
 
-    @abc.abstractclassmethod
+    @abstractclassmethod
     def to_value(cls, data):
         """Convert loaded data to an attribute's value."""
         raise NotImplementedError(common.OVERRIDE_MESSAGE)
 
-    @abc.abstractclassmethod
+    @abstractclassmethod
     def to_data(cls, value):
         """Convert an attribute to data optimized for dumping."""
         raise NotImplementedError(common.OVERRIDE_MESSAGE)
+
+
+class Container(Mappable, Converter, metaclass=ABCMeta):
+    """Base class for mutable attribute converters."""
+
+    @classmethod
+    def create_default(cls):
+        return cls.__new__(cls)
+
+    @classmethod
+    def to_value(cls, data):
+        value = cls.create_default()
+        value.update_value(data, strict=False)
+        return value
+
+    @abstractmethod
+    def update_value(self, data, strict):  # pragma: no cover (abstract method)
+        """Update the attribute's value from loaded data."""
+        raise NotImplementedError(common.OVERRIDE_MESSAGE)
+
+    def format_data(self):
+        """Format the attribute to data optimized for dumping."""
+        return self.to_data(self)

yorm/bases/mappable.py

@@ -4,7 +4,6 @@
 import functools
 
 from .. import common
-from ..mapper import get_mapper
 
 
 log = common.logger(__name__)
@@ -22,11 +21,11 @@ def fetch_before(method):
     def wrapped(self, *args, **kwargs):
         """Decorated method."""
         if not _private_call(method, args):
-            mapper = get_mapper(self)
+            mapper = common.get_mapper(self)
             if mapper and mapper.modified:
                 log.debug("Fetching before call: %s", method.__name__)
                 mapper.fetch()
-                if mapper.auto_store:
+                if mapper.store_after_fetch:
                     mapper.store()
                     mapper.modified = False
 
@@ -49,7 +48,7 @@ def wrapped(self, *args, **kwargs):
         result = method(self, *args, **kwargs)
 
         if not _private_call(method, args):
-            mapper = get_mapper(self)
+            mapper = common.get_mapper(self)
             if mapper and mapper.auto:
                 log.debug("Storing after call: %s", method.__name__)
                 mapper.store()
@@ -70,6 +69,7 @@ def _private_call(method, args, prefix='_'):
         return False
 
 
+# TODO: move these methods inside of `Container`
 class Mappable(metaclass=abc.ABCMeta):
     """Base class for objects with attributes mapped to file."""
 

yorm/common.py

@@ -6,6 +6,7 @@
 
 # CONSTANTS ####################################################################
 
+MAPPER = '__mapper__'
 
 PRINT_VERBOSITY = 0  # minimum verbosity to using `print`
 STR_VERBOSITY = 3  # minimum verbosity to use verbose `__str__`
@@ -49,3 +50,20 @@ def __init__(self, getter):
 
     def __get__(self, instance, owner):
         return self.getter(owner)
+
+
+# FUNCTIONS ####################################################################
+
+
+def get_mapper(obj):
+    """Get the `Mapper` instance attached to an object."""
+    try:
+        return object.__getattribute__(obj, MAPPER)
+    except AttributeError:
+        return None
+
+
+def set_mapper(obj, mapper):
+    """Attach a `Mapper` instance to an object."""
+    setattr(obj, MAPPER, mapper)
+    return mapper

yorm/mapper.py

@@ -3,29 +3,12 @@
 import functools
 from pprint import pformat
 
-from . import common, diskutils, exceptions, settings
+from . import common, diskutils, exceptions, types, settings
 from .bases import Container
 
-MAPPER = '__mapper__'
-
 log = common.logger(__name__)
 
 
-def get_mapper(obj):
-    """Get `Mapper` instance attached to an object."""
-    try:
-        return object.__getattribute__(obj, MAPPER)
-    except AttributeError:
-        return None
-
-
-def set_mapper(obj, path, attrs, auto=True):
-    """Create and attach a `Mapper` instance to an object."""
-    mapper = Mapper(obj, path, attrs, auto=auto)
-    setattr(obj, MAPPER, mapper)
-    return mapper
-
-
 def file_required(create=False):
     """Decorator for methods that require the file to exist.
 
@@ -97,15 +80,16 @@ class Mapper:
 
     """
 
-    def __init__(self, obj, path, attrs, auto=True):
+    def __init__(self, obj, path, attrs, *, auto=True, strict=True):
         self._obj = obj
         self.path = path
         self.attrs = attrs
         self.auto = auto
+        self.strict = strict
 
-        self.auto_store = False
         self.exists = diskutils.exists(self.path)
         self.deleted = False
+        self.store_after_fetch = False
         self._activity = False
         self._timestamp = 0
         self._fake = ""
@@ -159,7 +143,7 @@ def text(self, text):
             self._fake = text
         else:
             self._write(text)
-        log.trace("Text wrote: \n%s", text[:-1])
+        log.trace("Text wrote: \n%s", text.rstrip())
         self.modified = True
 
     def create(self):
@@ -193,17 +177,19 @@ def fetch(self):
             try:
                 converter = self.attrs[name]
             except KeyError:
-                # TODO: determine if runtime import is the best way to avoid
-                # cyclic import
-                from .types import match
-                converter = match(name, data)
-                self.attrs[name] = converter
+                if self.strict:
+                    msg = "Ignored unknown file attribute: %s = %r"
+                    log.warning(msg, name, data)
+                    continue
+                else:
+                    converter = types.match(name, data)
+                    self.attrs[name] = converter
 
             # Convert the loaded attribute
             attr = getattr(self._obj, name, None)
             if all((isinstance(attr, converter),
                     issubclass(converter, Container))):
-                attr.update_value(data)
+                attr.update_value(data, strict=self.strict)
             else:
                 attr = converter.to_value(data)
                 setattr(self._obj, name, attr)
@@ -214,13 +200,26 @@ def fetch(self):
         for name, converter in attrs2.items():
             if not hasattr(self._obj, name):
                 value = converter.to_value(None)
-                msg = "Fetched default value for missing attribute: %s = %r"
+                msg = "Default value for missing object attribute: %s = %r"
                 log.warning(msg, name, value)
                 setattr(self._obj, name, value)
 
         # Set meta attributes
         self.modified = False
 
+    def _remap(self, obj, root):
+        """Restore mapping on nested attributes."""
+        if isinstance(obj, Container):
+            common.set_mapper(obj, root)
+
+            if isinstance(obj, dict):
+                for obj2 in obj.values():
+                    self._remap(obj2, root)
+            else:
+                assert isinstance(obj, list)
+                for obj2 in obj:
+                    self._remap(obj2, root)
+
     @file_required(create=True)
     @prevent_recursion
     def store(self):
@@ -233,11 +232,11 @@ def store(self):
             try:
                 value = getattr(self._obj, name)
             except AttributeError:
-                value = None
-                msg = "Storing default data for missing attribute '%s'..."
-                log.warning(msg, name)
-
-            data2 = converter.to_data(value)
+                data2 = converter.to_data(None)
+                msg = "Default data for missing object attribute: %s = %r"
+                log.warning(msg, name, data2)
+            else:
+                data2 = converter.to_data(value)
 
             log.trace("Data to store: %s = %r", name, data2)
             data[name] = data2
@@ -248,7 +247,7 @@ def store(self):
 
         # Set meta attributes
         self.modified = True
-        self.auto_store = self.auto
+        self.store_after_fetch = self.auto
 
     def delete(self):
         """Delete the object's file from the file system."""
@@ -277,16 +276,3 @@ def _write(self, text):
             self._fake = text
         else:
             diskutils.write(text, self.path)
-
-    def _remap(self, obj, root):
-        """Restore mapping on nested attributes."""
-        if isinstance(obj, Container):
-            setattr(obj, MAPPER, root)
-
-            if isinstance(obj, dict):
-                for obj2 in obj.values():
-                    self._remap(obj2, root)
-            else:
-                assert isinstance(obj, list)
-                for obj2 in obj:
-                    self._remap(obj2, root)