Merge pull request #1772 from QuLogic/py3k-hash

Python 3 hashing

lib/iris/_concatenate.py

@@ -146,6 +146,9 @@ def __new__(cls, coord, dims):
                                                       kwargs)
         return metadata
 
+    def __hash__(self):
+        return super(_CoordMetaData, self).__hash__()
+
     def __eq__(self, other):
         result = NotImplemented
         if isinstance(other, _CoordMetaData):

lib/iris/coords.py

@@ -210,6 +210,9 @@ def __add__(self, mod):
             bound = tuple([val + mod for val in bound])
         return Cell(point, bound)
 
+    def __hash__(self):
+        return super(Cell, self).__hash__()
+
     def __eq__(self, other):
         """
         Compares Cell equality depending on the type of the object to be
@@ -1391,6 +1394,11 @@ def __eq__(self, other):
 
     # The __ne__ operator from Coord implements the not __eq__ method.
 
+    # This is necessary for merging, but probably shouldn't be used otherwise.
+    # See #962 and #1772.
+    def __hash__(self):
+        return hash(id(self))
+
     def __getitem__(self, key):
         coord = super(DimCoord, self).__getitem__(key)
         coord.circular = self.circular and coord.shape == self.shape
@@ -1592,6 +1600,11 @@ def bounds(self, bounds):
                                  "shape.")
         self._bounds = bounds
 
+    # This is necessary for merging, but probably shouldn't be used otherwise.
+    # See #962 and #1772.
+    def __hash__(self):
+        return hash(id(self))
+
 
 class CellMethod(iris.util._OrderedHashable):
     """

lib/iris/cube.py

@@ -2736,6 +2736,12 @@ def __ne__(self, other):
             result = not result
         return result
 
+    # Must supply __hash__, Python 3 does not enable it if __eq__ is defined
+    # This is necessary for merging, but probably shouldn't be used otherwise.
+    # See #962 and #1772.
+    def __hash__(self):
+        return hash(id(self))
+
     def __add__(self, other):
         return iris.analysis.maths.add(self, other, ignore=True)
     __radd__ = __add__

lib/iris/fileformats/_structured_array_identification.py

@@ -110,6 +110,9 @@ def __new__(cls, stride, unique_ordered_values):
         self.size = len(unique_ordered_values)
         return self
 
+    def __hash__(self):
+        return super(ArrayStructure, self).__hash__()
+
     def __eq__(self, other):
         stride = getattr(other, 'stride', None)
         arr = getattr(other, 'unique_ordered_values', None)

lib/iris/fileformats/cf.py

@@ -167,6 +167,10 @@ def __ne__(self, other):
         # CF variable names are unique.
         return self.cf_name != other.cf_name
 
+    def __hash__(self):
+        # CF variable names are unique.
+        return hash(self.cf_name)
+
     def __getattr__(self, name):
         # Accessing netCDF attributes is surprisingly slow. Since
         # they're often read repeatedly, caching the values makes things

lib/iris/fileformats/pp.py

@@ -344,6 +344,9 @@ def lbuser6(self):
     def is_valid(self):
         return '?' not in str(self)
 
+    def __hash__(self):
+        return super(STASH, self).__hash__()
+
     def __eq__(self, other):
         if isinstance(other, six.string_types):
             return super(STASH, self).__eq__(STASH.from_msi(other))

lib/iris/unit.py

@@ -1741,6 +1741,8 @@ def _identity(self):
         # iris.util._OrderedHashable.
         return (self.name, self.calendar)
 
+    __hash__ = iris.util._OrderedHashable.__hash__
+
     def __eq__(self, other):
         """
         Compare the two units for equality and return the boolean result.