Merge pull request #19 from kxepal/pylint

Improve code quality

Author: stefankoegl

jsonpatch.py

@@ -30,31 +30,34 @@
 # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
 
+""" Apply JSON-Patches (RFC 6902) """
+
 from __future__ import unicode_literals
 
-""" Apply JSON-Patches (RFC 6902) """
+import collections
+import copy
+import functools
+import inspect
+import json
+import sys
+
+from jsonpointer import JsonPointer, JsonPointerException
 
 # Will be parsed by setup.py to determine package metadata
 __author__ = 'Stefan Kögl <stefan@skoegl.net>'
 __version__ = '1.3'
 __website__ = 'https://github.com/stefankoegl/python-json-patch'
 __license__ = 'Modified BSD License'
 
-import copy
-import sys
-import operator
-import collections
-
-import json
-
-import jsonpointer
 
+# pylint: disable=E0611,W0404
 if sys.version_info >= (3, 0):
-    basestring = (bytes, str)
+    basestring = (bytes, str)  # pylint: disable=C0103,W0622
+    from itertools import zip_longest
+else:
+    from itertools import izip_longest as zip_longest
 
 
-JsonPointerException = jsonpointer.JsonPointerException
-
 class JsonPatchException(Exception):
     """Base Json Patch exception"""
 
@@ -67,22 +70,23 @@ class JsonPatchConflict(JsonPatchException):
     - etc.
     """
 
+
 class JsonPatchTestFailed(JsonPatchException, AssertionError):
     """ A Test operation failed """
 
 
 def multidict(ordered_pairs):
     """Convert duplicate keys values to lists."""
     # read all values into lists
-    d = collections.defaultdict(list)
-    for k, v in ordered_pairs:
-        d[k].append(v)
+    mdict = collections.defaultdict(list)
+    for key, value in ordered_pairs:
+        mdict[key].append(value)
 
-    # unpack lists that have only 1 item
-    for k, v in d.items():
-        if len(v) == 1:
-            d[k] = v[0]
-    return dict(d)
+    return dict(
+        # unpack lists that have only 1 item
+        (key, values[0] if len(values) == 1 else values)
+        for key, values in mdict.items()
+    )
 
 
 def get_loadjson():
@@ -94,9 +98,6 @@ def get_loadjson():
     function with object_pairs_hook set to multidict for Python versions that
     support the parameter. """
 
-    import inspect
-    import functools
-
     argspec = inspect.getargspec(json.load)
     if 'object_pairs_hook' not in argspec.args:
         return json.load
@@ -123,12 +124,14 @@ def apply_patch(doc, patch, in_place=False):
     :rtype: dict
 
     >>> doc = {'foo': 'bar'}
-    >>> other = apply_patch(doc, [{'op': 'add', 'path': '/baz', 'value': 'qux'}])
+    >>> patch = [{'op': 'add', 'path': '/baz', 'value': 'qux'}]
+    >>> other = apply_patch(doc, patch)
     >>> doc is not other
     True
     >>> other == {'foo': 'bar', 'baz': 'qux'}
     True
-    >>> apply_patch(doc, [{'op': 'add', 'path': '/baz', 'value': 'qux'}], in_place=True) == {'foo': 'bar', 'baz': 'qux'}
+    >>> patch = [{'op': 'add', 'path': '/baz', 'value': 'qux'}]
+    >>> apply_patch(doc, patch, in_place=True) == {'foo': 'bar', 'baz': 'qux'}
     True
     >>> doc == other
     True
@@ -140,6 +143,7 @@ def apply_patch(doc, patch, in_place=False):
         patch = JsonPatch(patch)
     return patch.apply(doc, in_place)
 
+
 def make_patch(src, dst):
     """Generates patch by comparing of two document objects. Actually is
     a proxy to :meth:`JsonPatch.from_diff` method.
@@ -230,18 +234,16 @@ def __bool__(self):
     def __iter__(self):
         return iter(self.patch)
 
-
     def __hash__(self):
         return hash(tuple(self._ops))
 
-
     def __eq__(self, other):
         if not isinstance(other, JsonPatch):
             return False
+        return self._ops == other._ops
 
-        return len(list(self._ops)) == len(list(other._ops)) and \
-               all(map(operator.eq, self._ops, other._ops))
-
+    def __ne__(self, other):
+        return not(self == other)
 
     @classmethod
     def from_string(cls, patch_str):
@@ -298,7 +300,9 @@ def compare_dict(path, src, dst):
                     yield operation
             for key in dst:
                 if key not in src:
-                    yield {'op': 'add', 'path': '/'.join(path + [key]), 'value': dst[key]}
+                    yield {'op': 'add',
+                           'path': '/'.join(path + [key]),
+                           'value': dst[key]}
 
         def compare_list(path, src, dst):
             lsrc, ldst = len(src), len(dst)
@@ -309,7 +313,9 @@ def compare_list(path, src, dst):
             if lsrc < ldst:
                 for idx in range(lsrc, ldst):
                     current = path + [str(idx)]
-                    yield {'op': 'add', 'path': '/'.join(current), 'value': dst[idx]}
+                    yield {'op': 'add',
+                           'path': '/'.join(current),
+                           'value': dst[idx]}
             elif lsrc > ldst:
                 for idx in reversed(range(ldst, lsrc)):
                     yield {'op': 'remove', 'path': '/'.join(path + [str(idx)])}
@@ -322,7 +328,7 @@ def to_string(self):
 
     @property
     def _ops(self):
-        return map(self._get_operation, self.patch)
+        return tuple(map(self._get_operation, self.patch))
 
     def apply(self, obj, in_place=False):
         """Applies the patch to given object.
@@ -355,36 +361,35 @@ def _get_operation(self, operation):
             raise JsonPatchException("Operation must be a string")
 
         if op not in self.operations:
-            raise JsonPatchException("Unknown operation '%s'" % op)
+            raise JsonPatchException("Unknown operation {0!r}".format(op))
 
         cls = self.operations[op]
         return cls(operation)
 
 
-
 class PatchOperation(object):
     """A single operation inside a JSON Patch."""
 
     def __init__(self, operation):
         self.location = operation['path']
-        self.pointer = jsonpointer.JsonPointer(self.location)
+        self.pointer = JsonPointer(self.location)
         self.operation = operation
 
     def apply(self, obj):
         """Abstract method that applies patch operation to specified object."""
         raise NotImplementedError('should implement patch operation.')
 
-
     def __hash__(self):
         return hash(frozenset(self.operation.items()))
 
-
     def __eq__(self, other):
         if not isinstance(other, PatchOperation):
             return False
-
         return self.operation == other.operation
 
+    def __ne__(self, other):
+        return not(self == other)
+
 
 class RemoveOperation(PatchOperation):
     """Removes an object property or an array element."""
@@ -406,30 +411,25 @@ def apply(self, obj):
         value = self.operation["value"]
         subobj, part = self.pointer.to_last(obj)
 
-        # type is already checked in to_last(), so we assert here
-        # for consistency
-        assert isinstance(subobj, list) or isinstance(subobj, dict), \
-            "invalid document type %s" (type(doc),)
-
         if isinstance(subobj, list):
-
             if part == '-':
-                subobj.append(value)
+                subobj.append(value)  # pylint: disable=E1103
 
             elif part > len(subobj) or part < 0:
                 raise JsonPatchConflict("can't insert outside of list")
 
             else:
-                subobj.insert(part, value)
+                subobj.insert(part, value)  # pylint: disable=E1103
 
         elif isinstance(subobj, dict):
             if part is None:
-                # we're replacing the root
-                obj = value
-
+                obj = value  # we're replacing the root
             else:
                 subobj[part] = value
 
+        else:
+            raise TypeError("invalid document type {0}".format(type(subobj)))
+
         return obj
 
 
@@ -440,11 +440,6 @@ def apply(self, obj):
         value = self.operation["value"]
         subobj, part = self.pointer.to_last(obj)
 
-        # type is already checked in to_last(), so we assert here
-        # for consistency
-        assert isinstance(subobj, list) or isinstance(subobj, dict), \
-            "invalid document type %s" (type(doc),)
-
         if part is None:
             return value
 
@@ -454,8 +449,10 @@ def apply(self, obj):
 
         elif isinstance(subobj, dict):
             if not part in subobj:
-                raise JsonPatchConflict("can't replace non-existant object '%s'"
-                                        "" % part)
+                msg = "can't replace non-existent object '{0}'".format(part)
+                raise JsonPatchConflict(msg)
+        else:
+            raise TypeError("invalid document type {0}".format(type(subobj)))
 
         subobj[part] = value
         return obj
@@ -465,15 +462,24 @@ class MoveOperation(PatchOperation):
     """Moves an object property or an array element to new location."""
 
     def apply(self, obj):
-        from_ptr = jsonpointer.JsonPointer(self.operation['from'])
+        from_ptr = JsonPointer(self.operation['from'])
         subobj, part = from_ptr.to_last(obj)
         value = subobj[part]
 
         if self.pointer.contains(from_ptr):
             raise JsonPatchException('Cannot move values into its own children')
 
-        obj = RemoveOperation({'op': 'remove', 'path': self.operation['from']}).apply(obj)
-        obj = AddOperation({'op': 'add', 'path': self.location, 'value': value}).apply(obj)
+        obj = RemoveOperation({
+            'op': 'remove',
+            'path': self.operation['from']
+        }).apply(obj)
+
+        obj = AddOperation({
+            'op': 'add',
+            'path': self.location,
+            'value': value
+        }).apply(obj)
+
         return obj
 
 
@@ -487,14 +493,15 @@ def apply(self, obj):
                 val = subobj
             else:
                 val = self.pointer.walk(subobj, part)
-
         except JsonPointerException as ex:
             raise JsonPatchTestFailed(str(ex))
 
         if 'value' in self.operation:
             value = self.operation['value']
             if val != value:
-                raise JsonPatchTestFailed('%s is not equal to tested value %s (types %s and %s)' % (val, value, type(val), type(value)))
+                msg = '{0} ({1}) is not equal to tested value {2} ({3})'
+                raise JsonPatchTestFailed(msg.format(val, type(val),
+                                                     value, type(value)))
 
         return obj
 
@@ -503,8 +510,14 @@ class CopyOperation(PatchOperation):
     """ Copies an object property or an array element to a new location """
 
     def apply(self, obj):
-        from_ptr = jsonpointer.JsonPointer(self.operation['from'])
+        from_ptr = JsonPointer(self.operation['from'])
         subobj, part = from_ptr.to_last(obj)
         value = copy.deepcopy(subobj[part])
-        obj = AddOperation({'op': 'add', 'path': self.location, 'value': value}).apply(obj)
+
+        obj = AddOperation({
+            'op': 'add',
+            'path': self.location,
+            'value': value
+        }).apply(obj)
+
         return obj