From 3a8896e7e0af852192d26dcaee5fae6fbd70f1f0 Mon Sep 17 00:00:00 2001
From: Stephan Hoyer <shoyer@climate.com>
Date: Fri, 1 Jan 2016 15:09:10 -0800
Subject: [PATCH] Check that dimensions are all valid when using reindex

This fixes the underlying issue that allowed GH693.
---
 xray/core/alignment.py    | 7 ++++++-
 xray/core/dataarray.py    | 4 +++-
 xray/core/dataset.py      | 8 +++++++-
 xray/core/merge.py        | 7 +++++--
 xray/test/test_dataset.py | 4 ++++
 5 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/xray/core/alignment.py b/xray/core/alignment.py
index bc4010c2d87..d5b0692aca1 100644
--- a/xray/core/alignment.py
+++ b/xray/core/alignment.py
@@ -84,7 +84,12 @@ def align(*objects, **kwargs):
                         % list(kwargs))
 
     joined_indexes = _join_indexes(join, objects)
-    return tuple(obj.reindex(copy=copy, **joined_indexes) for obj in objects)
+    result = []
+    for obj in objects:
+        valid_indexers = dict((k, v) for k, v in joined_indexes.items()
+                              if k in obj.dims)
+        result.append(obj.reindex(copy=copy, **valid_indexers))
+    return tuple(result)
 
 
 def partial_align(*objects, **kwargs):
diff --git a/xray/core/dataarray.py b/xray/core/dataarray.py
index 3db54faf8b6..87a297d7780 100644
--- a/xray/core/dataarray.py
+++ b/xray/core/dataarray.py
@@ -658,8 +658,10 @@ def reindex_like(self, other, method=None, tolerance=None, copy=True):
         DataArray.reindex
         align
         """
+        indexers = dict((k, v) for k, v in other.indexes.items()
+                        if k in self.dims)
         return self.reindex(method=method, tolerance=tolerance, copy=copy,
-                            **other.indexes)
+                            **indexers)
 
     def reindex(self, method=None, tolerance=None, copy=True, **indexers):
         """Conform this object onto a new set of indexes, filling in
diff --git a/xray/core/dataset.py b/xray/core/dataset.py
index 964b298c1be..62de1c43273 100644
--- a/xray/core/dataset.py
+++ b/xray/core/dataset.py
@@ -1152,8 +1152,10 @@ def reindex_like(self, other, method=None, tolerance=None, copy=True):
         Dataset.reindex
         align
         """
+        indexers = dict((k, v) for k, v in other.indexes.items()
+                        if k in self.dims)
         return self.reindex(method=method, copy=copy, tolerance=tolerance,
-                            **other.indexes)
+                            **indexers)
 
     def reindex(self, indexers=None, method=None, tolerance=None, copy=True, **kw_indexers):
         """Conform this object onto a new set of indexes, filling in
@@ -1203,6 +1205,10 @@ def reindex(self, indexers=None, method=None, tolerance=None, copy=True, **kw_in
             # shortcut
             return self.copy(deep=True) if copy else self
 
+        bad_dims = [d for d in indexers if d not in self.dims]
+        if bad_dims:
+            raise ValueError('invalid reindex dimensions: %s' % bad_dims)
+
         variables = alignment.reindex_variables(
             self.variables, self.indexes, indexers, method, tolerance, copy=copy)
         return self._replace_vars_and_dims(variables)
diff --git a/xray/core/merge.py b/xray/core/merge.py
index 5f6c7ede787..0b7d61592a6 100644
--- a/xray/core/merge.py
+++ b/xray/core/merge.py
@@ -151,8 +151,11 @@ def _reindex_variables_against(variables, indexes, copy=False):
     """Reindex all DataArrays in the provided dict, leaving other values alone.
     """
     alignable = [k for k, v in variables.items() if hasattr(v, 'indexes')]
-    aligned = [variables[a].reindex(copy=copy, **indexes)
-               for a in alignable]
+    aligned = []
+    for a in alignable:
+        valid_indexes = dict((k, v) for k, v in indexes.items()
+                             if k in variables[a].dims)
+        aligned.append(variables[a].reindex(copy=copy, **valid_indexes))
     new_variables = OrderedDict(variables)
     new_variables.update(zip(alignable, aligned))
     return new_variables
diff --git a/xray/test/test_dataset.py b/xray/test/test_dataset.py
index 7213d3293d9..18c2279c392 100644
--- a/xray/test/test_dataset.py
+++ b/xray/test/test_dataset.py
@@ -868,6 +868,10 @@ def test_reindex(self):
         with self.assertRaisesRegexp(ValueError, 'dictionary'):
             data.reindex('foo')
 
+        # invalid dimension
+        with self.assertRaisesRegexp(ValueError, 'invalid reindex dim'):
+            data.reindex(invalid=0)
+
         # out of order
         expected = data.sel(dim1=data['dim1'][:10:-1])
         actual = data.reindex(dim1=data['dim1'][:10:-1])