deprecate compat & encoding (#2703)

* deprecate compat & encoding

* stacklevel

* whatsnew

* imports

* merge conflicts

* remove deprecations

* removal date

.github/stale.yml

@@ -28,7 +28,8 @@ staleLabel: stale
 # Comment to post when marking as stale. Set to `false` to disable
 markComment: |
   In order to maintain a list of currently relevant issues, we mark issues as stale after a period of inactivity
-  If this issue remains relevant, please comment here; otherwise it will be marked as closed automatically
+
+  If this issue remains relevant, please comment here or remove the `stale` label; otherwise it will be marked as closed automatically
 
 # Comment to post when removing the stale label.
 # unmarkComment: >

doc/whats-new.rst

@@ -24,6 +24,10 @@ Breaking changes
 - Remove support for Python 2. This is the first version of xarray that is
   Python 3 only. (:issue:`1876`).
   By `Joe Hamman <https://github.com/jhamman>`_.
+- The `compat` argument to `Dataset` and the `encoding` argument to 
+  `DataArray` are deprecated and will be removed in a future release.
+  (:issue:`1188`)
+  By `Maximilian Roos <https://github.com/max-sixty>`_.
 
 Enhancements
 ~~~~~~~~~~~~

xarray/core/alignment.py

@@ -495,7 +495,7 @@ def _broadcast_array(array):
         coords = OrderedDict(array.coords)
         coords.update(common_coords)
         return DataArray(data, coords, data.dims, name=array.name,
-                         attrs=array.attrs, encoding=array.encoding)
+                         attrs=array.attrs)
 
     def _broadcast_dataset(ds):
         data_vars = OrderedDict(

xarray/core/dataarray.py

@@ -12,15 +12,13 @@
 from .alignment import align, reindex_like_indexers
 from .common import AbstractArray, DataWithCoords
 from .coordinates import (
-    DataArrayCoordinates, LevelCoordinatesSource,
-    assert_coordinate_consistent, remap_label_indexers)
+    DataArrayCoordinates, LevelCoordinatesSource, assert_coordinate_consistent,
+    remap_label_indexers)
 from .dataset import Dataset, merge_indexes, split_indexes
 from .formatting import format_item
-from .indexes import default_indexes, Indexes
+from .indexes import Indexes, default_indexes
 from .options import OPTIONS
-from .utils import (
-    _check_inplace, decode_numpy_dict_values, either_dict_or_kwargs,
-    ensure_us_time_resolution)
+from .utils import _check_inplace, either_dict_or_kwargs
 from .variable import (
     IndexVariable, Variable, as_compatible_data, as_variable,
     assert_unique_multiindex_level_names)
@@ -192,13 +190,16 @@ def __init__(self, data, coords=None, dims=None, name=None,
         attrs : dict_like or None, optional
             Attributes to assign to the new instance. By default, an empty
             attribute dictionary is initialized.
-        encoding : dict_like or None, optional
-            Dictionary specifying how to encode this array's data into a
-            serialized format like netCDF4. Currently used keys (for netCDF)
-            include '_FillValue', 'scale_factor', 'add_offset', 'dtype',
-            'units' and 'calendar' (the later two only for datetime arrays).
-            Unrecognized keys are ignored.
+        encoding : deprecated
         """
+
+        if encoding is not None:
+            warnings.warn(
+                'The `encoding` argument to `DataArray` is deprecated, and . '
+                'will be removed in 0.13. '
+                'Instead, specify the encoding when writing to disk or '
+                'set the `encoding` attribute directly.',
+                FutureWarning, stacklevel=2)
         if fastpath:
             variable = data
             assert dims is None

xarray/core/dataset.py

@@ -13,16 +13,16 @@
 import xarray as xr
 
 from . import (
-    alignment, dtypes, duck_array_ops, formatting, groupby,
-    indexing, ops, pdcompat, resample, rolling, utils)
+    alignment, dtypes, duck_array_ops, formatting, groupby, indexing, ops,
+    pdcompat, resample, rolling, utils)
 from ..coding.cftimeindex import _parse_array_of_cftime_strings
 from .alignment import align
 from .common import (
     ALL_DIMS, DataWithCoords, ImplementsDatasetReduce,
     _contains_datetime_like_objects)
 from .coordinates import (
-    DatasetCoordinates, LevelCoordinatesSource,
-    assert_coordinate_consistent, remap_label_indexers)
+    DatasetCoordinates, LevelCoordinatesSource, assert_coordinate_consistent,
+    remap_label_indexers)
 from .indexes import Indexes, default_indexes
 from .merge import (
     dataset_merge_method, dataset_update_method, merge_data_and_coords,
@@ -31,8 +31,8 @@
 from .pycompat import dask_array_type
 from .utils import (
     Frozen, SortedKeysDict, _check_inplace, datetime_to_numeric,
-    decode_numpy_dict_values, either_dict_or_kwargs, ensure_us_time_resolution,
-    hashable, maybe_wrap_array)
+    decode_numpy_dict_values, either_dict_or_kwargs, hashable,
+    maybe_wrap_array)
 from .variable import IndexVariable, Variable, as_variable, broadcast_variables
 
 # list of attributes of pd.DatetimeIndex that are ndarrays of time info
@@ -324,7 +324,7 @@ class Dataset(Mapping, ImplementsDatasetReduce, DataWithCoords):
     _resample_cls = resample.DatasetResample
 
     def __init__(self, data_vars=None, coords=None, attrs=None,
-                 compat='broadcast_equals'):
+                 compat=None):
         """To load data from a file or file-like object, use the `open_dataset`
         function.
 
@@ -348,16 +348,17 @@ def __init__(self, data_vars=None, coords=None, attrs=None,
             name.
         attrs : dict-like, optional
             Global attributes to save on this dataset.
-        compat : {'broadcast_equals', 'equals', 'identical'}, optional
-            String indicating how to compare variables of the same name for
-            potential conflicts when initializing this dataset:
-
-            - 'broadcast_equals': all values must be equal when variables are
-              broadcast against each other to ensure common dimensions.
-            - 'equals': all values and dimensions must be the same.
-            - 'identical': all values, dimensions and attributes must be the
-              same.
+        compat : deprecated
         """
+
+        if compat is not None:
+            warnings.warn(
+                'The `compat` argument to Dataset is deprecated and will be '
+                'removed in 0.13.'
+                'Instead, use `merge` to control how variables are combined',
+                FutureWarning, stacklevel=2)
+        else:
+            compat = 'broadcast_equals'
         self._variables = OrderedDict()
         self._coord_names = set()
         self._dims = {}

xarray/tests/test_dataarray.py

@@ -258,7 +258,7 @@ def test_constructor(self):
         expected = Dataset({None: (['x', 'y'], data, {'bar': 2})})[None]
         assert_identical(expected, actual)
 
-        actual = DataArray(data, dims=['x', 'y'], encoding={'bar': 2})
+        actual = DataArray(data, dims=['x', 'y'])
         expected = Dataset({None: (['x', 'y'], data, {}, {'bar': 2})})[None]
         assert_identical(expected, actual)
 
@@ -296,7 +296,7 @@ def test_constructor_from_self_described(self):
         expected = DataArray(data,
                              coords={'x': ['a', 'b'], 'y': [-1, -2]},
                              dims=['x', 'y'], name='foobar',
-                             attrs={'bar': 2}, encoding={'foo': 3})
+                             attrs={'bar': 2})
         actual = DataArray(expected)
         assert_identical(expected, actual)
 

xarray/tests/test_dataset.py

@@ -1,10 +1,10 @@
 # -*- coding: utf-8 -*-
+import pickle
 import sys
 import warnings
 from collections import OrderedDict
 from copy import copy, deepcopy
 from io import StringIO
-import pickle
 from textwrap import dedent
 
 import numpy as np
@@ -354,13 +354,9 @@ def test_constructor_pandas_single(self):
     def test_constructor_compat(self):
         data = OrderedDict([('x', DataArray(0, coords={'y': 1})),
                             ('y', ('z', [1, 1, 1]))])
-        with pytest.raises(MergeError):
-            Dataset(data, compat='equals')
         expected = Dataset({'x': 0}, {'y': ('z', [1, 1, 1])})
         actual = Dataset(data)
         assert_identical(expected, actual)
-        actual = Dataset(data, compat='broadcast_equals')
-        assert_identical(expected, actual)
 
         data = OrderedDict([('y', ('z', [1, 1, 1])),
                             ('x', DataArray(0, coords={'y': 1}))])