From 6bef1afbeb646a02b9c34be7ec0d6bbb70bbac41 Mon Sep 17 00:00:00 2001
From: Stephan Hoyer <shoyer@gmail.com>
Date: Sat, 11 Nov 2017 22:02:50 -0800
Subject: [PATCH] Validate shape of DataArray coords with same name as
 dimensions

Fixes GH1709
---
 doc/whats-new.rst              |  4 ++++
 xarray/core/dataarray.py       | 12 +++++++++---
 xarray/core/variable.py        |  2 +-
 xarray/tests/test_dataarray.py |  3 +++
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 668e70a42d9..1c6dfba138e 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -54,6 +54,10 @@ Bug fixes
   (:issue:`1697`).
   By `Stephan Hoyer <https://github.com/shoyer>`_.
 
+- Validate the shape of coordinates with names matching dimensions in the
+  DataArray constructor (:issue:`1709`).
+  By `Stephan Hoyer <https://github.com/shoyer>`_.
+
 Testing
 ~~~~~~~
 
diff --git a/xarray/core/dataarray.py b/xarray/core/dataarray.py
index 1dac72335d2..0516b473994 100644
--- a/xarray/core/dataarray.py
+++ b/xarray/core/dataarray.py
@@ -35,7 +35,7 @@ def _infer_coords_and_dims(shape, coords, dims):
     """All the logic for creating a new DataArray"""
 
     if (coords is not None and not utils.is_dict_like(coords) and
-        len(coords) != len(shape)):
+            len(coords) != len(shape)):
         raise ValueError('coords is not dict-like, but it has %s items, '
                          'which does not match the %s dimensions of the '
                          'data' % (len(coords), len(shape)))
@@ -50,8 +50,8 @@ def _infer_coords_and_dims(shape, coords, dims):
             if utils.is_dict_like(coords):
                 # deprecated in GH993, removed in GH1539
                 raise ValueError('inferring DataArray dimensions from '
-                                 'dictionary like ``coords`` has been '
-                                 'deprecated. Use an explicit list of '
+                                 'dictionary like ``coords`` is no longer '
+                                 'supported. Use an explicit list of '
                                  '``dims`` instead.')
             for n, (dim, coord) in enumerate(zip(dims, coords)):
                 coord = as_variable(coord,
@@ -87,6 +87,12 @@ def _infer_coords_and_dims(shape, coords, dims):
                                  'length %s on the data but length %s on '
                                  'coordinate %r' % (d, sizes[d], s, k))
 
+        if k in sizes and v.shape != (sizes[k],):
+            raise ValueError('coordinate %r is a DataArray dimension, but '
+                             'it has shape %r rather than expected shape %r '
+                             'matching the dimension size'
+                             % (k, v.shape, (sizes[k],)))
+
     assert_unique_multiindex_level_names(new_coords)
 
     return new_coords, dims
diff --git a/xarray/core/variable.py b/xarray/core/variable.py
index aa64dcab1fc..f2bc004c668 100644
--- a/xarray/core/variable.py
+++ b/xarray/core/variable.py
@@ -96,7 +96,7 @@ def as_variable(obj, name=None):
                             '{}'.format(obj))
     elif utils.is_scalar(obj):
         obj = Variable([], obj)
-    elif (isinstance(obj, (pd.Index, IndexVariable)) and obj.name is not None):
+    elif isinstance(obj, (pd.Index, IndexVariable)) and obj.name is not None:
         obj = Variable(obj.name, obj)
     elif name is not None:
         data = as_compatible_data(obj)
diff --git a/xarray/tests/test_dataarray.py b/xarray/tests/test_dataarray.py
index d39232c04c8..c86f706f2ce 100644
--- a/xarray/tests/test_dataarray.py
+++ b/xarray/tests/test_dataarray.py
@@ -298,6 +298,9 @@ def test_constructor_invalid(self):
             DataArray(np.random.rand(4, 4),
                       [('x', self.mindex), ('level_1', range(4))])
 
+        with raises_regex(ValueError, 'matching the dimension size'):
+            DataArray(data, coords={'x': 0}, dims=['x', 'y'])
+
     def test_constructor_from_self_described(self):
         data = [[-0.1, 21], [0, 2]]
         expected = DataArray(data,