Compat and encoding deprecation to 0.14 (#3294)

* push the removal of the compat and encoding arguments from Dataset/DataArray back to 0.14

* require dim argument to concat

* Update whats-new.rst

doc/whats-new.rst

@@ -48,8 +48,8 @@ Breaking changes
   - Any user code that defines custom subclasses of xarray classes must now explicitly
     define ``__slots__`` itself. Subclasses that don't add any attributes must state so
     by defining ``__slots__ = ()`` right after the class header.
-    Omitting ``__slots__`` will now cause a ``FutureWarning`` to be logged, and a hard
-    crash in a later release.
+    Omitting ``__slots__`` will now cause a ``FutureWarning`` to be logged, and will raise an
+    error in a later release.
 
   (:issue:`3250`) by `Guido Imperiale <https://github.com/crusaderky>`_.
 - :py:meth:`~Dataset.to_dataset` requires ``name`` to be passed as a kwarg (previously ambiguous 

xarray/core/dataarray.py

@@ -315,7 +315,7 @@ def __init__(
         if encoding is not None:
             warnings.warn(
                 "The `encoding` argument to `DataArray` is deprecated, and . "
-                "will be removed in 0.13. "
+                "will be removed in 0.14. "
                 "Instead, specify the encoding when writing to disk or "
                 "set the `encoding` attribute directly.",
                 FutureWarning,

xarray/core/dataset.py

@@ -489,7 +489,7 @@ def __init__(
         if compat is not None:
             warnings.warn(
                 "The `compat` argument to Dataset is deprecated and will be "
-                "removed in 0.13."
+                "removed in 0.14."
                 "Instead, use `merge` to control how variables are combined",
                 FutureWarning,
                 stacklevel=2,