From 84907b0aac9f55f6f815fe83d86f6d0480f0fe8e Mon Sep 17 00:00:00 2001
From: dcherian <deepak@cherian.net>
Date: Tue, 17 Dec 2019 07:42:04 -0700
Subject: [PATCH] concat keep attrs from first variable.

Fixes #2060
Fixes #2575
---
 doc/whats-new.rst           |  3 +++
 xarray/core/variable.py     |  5 +++--
 xarray/tests/test_concat.py | 13 +++++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 1f60d457432..a15e7e35cb8 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -25,6 +25,9 @@ Breaking changes
 
 New Features
 ~~~~~~~~~~~~
+- :py:func:`xarray.concat` now preserves attributes from the first Variable.
+  (:issue:`2575`, :issue:`2060`, :issue:`1614`)
+  By `Deepak Cherian <https://github.com/dcherian>`_.
 - :py:meth:`Dataset.quantile`, :py:meth:`DataArray.quantile` and ``GroupBy.quantile``
   now work with dask Variables.
   By `Deepak Cherian <https://github.com/dcherian>`_.
diff --git a/xarray/core/variable.py b/xarray/core/variable.py
index aa04cffb5ea..ccfa2217abb 100644
--- a/xarray/core/variable.py
+++ b/xarray/core/variable.py
@@ -1622,8 +1622,9 @@ def concat(cls, variables, dim="concat_dim", positions=None, shortcut=False):
         if not shortcut:
             for var in variables:
                 if var.dims != first_var.dims:
-                    raise ValueError("inconsistent dimensions")
-                utils.remove_incompatible_items(attrs, var.attrs)
+                    raise ValueError(
+                        f"Variable has dimensions {list(var.dims)} but first Variable has dimensions {list(first_var.dims)}"
+                    )
 
         return cls(dims, data, attrs, encoding)
 
diff --git a/xarray/tests/test_concat.py b/xarray/tests/test_concat.py
index 0661ebb7a38..def5abc942f 100644
--- a/xarray/tests/test_concat.py
+++ b/xarray/tests/test_concat.py
@@ -462,3 +462,16 @@ def test_concat_join_kwarg(self):
         for join in expected:
             actual = concat([ds1, ds2], join=join, dim="x")
             assert_equal(actual, expected[join].to_array())
+
+
+@pytest.mark.parametrize("attr1", ({"a": {"meta": [10, 20, 30]}}, {"a": [1, 2, 3]}, {}))
+@pytest.mark.parametrize("attr2", ({"a": [1, 2, 3]}, {}))
+def test_concat_attrs_first_variable(attr1, attr2):
+
+    arrs = [
+        DataArray([[1], [2]], dims=["x", "y"], attrs=attr1),
+        DataArray([[3], [4]], dims=["x", "y"], attrs=attr2),
+    ]
+
+    concat_attrs = concat(arrs, "y").attrs
+    assert concat_attrs == attr1