resolve merge conflicts

.codecov.yml

@@ -1,3 +1,9 @@
+codecov:
+  ci:
+    # by default, codecov doesn't recognize azure as a CI provider
+    - dev.azure.com
+  require_ci_to_pass: yes
+
 coverage:
   status:
     project:
@@ -7,7 +13,4 @@ coverage:
     patch: false
     changes: false
 
-comment:
-  layout: "header, diff"
-  behavior: default
-  require_changes: no
+comment: off

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,29 +1,28 @@
 ---
-name: Bug report
-about: Create a report to help us improve
+name: Bug report / Feature request
+about: 'Post a problem or idea'
 title: ''
 labels: ''
 assignees: ''
 
 ---
 
 #### MCVE Code Sample
-
-In order for the maintainers to efficiently understand and prioritize issues, we ask you post a "Minimal, Complete and Verifiable Example" (MCVE): http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports
+<!-- In order for the maintainers to efficiently understand and prioritize issues, we ask you post a "Minimal, Complete and Verifiable Example" (MCVE): http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports -->
 
 ```python
 # Your code here
 
 ```
 
-#### Problem Description
+#### Expected Output
 
-[this should explain **why** the current behavior is a problem and why the expected output is a better solution.]
 
-#### Expected Output
+#### Problem Description
+<!-- this should explain why the current behavior is a problem and why the expected output is a better solution -->
 
-#### Output of ``xr.show_versions()``
 
+#### Output of ``xr.show_versions()``
 <details>
 # Paste the output here xr.show_versions() here
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,4 +2,5 @@
 
  - [ ] Closes #xxxx
  - [ ] Tests added
+ - [ ] Passes `black . && mypy . && flake8`
  - [ ] Fully documented, including `whats-new.rst` for all changes and `api.rst` for new API

.gitignore

@@ -66,6 +66,7 @@ dask-worker-space/
 doc/_build
 doc/generated
 xarray/version.py
+xarray/tests/data/*.grib.*.idx
 
 # Sync tools
 Icon*

.pre-commit-config.yaml

@@ -0,0 +1,29 @@
+# https://pre-commit.com/
+# https://github.com/python/black#version-control-integration
+repos:
+  - repo: https://github.com/python/black
+    rev: stable
+    hooks:
+      - id: black
+        language_version: python3.7
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.2.3
+    hooks:
+      - id: flake8
+  - repo: https://github.com/pre-commit/mirrors-mypy
+    rev: v0.720  # Must match ci/requirements/*.yml
+    hooks:
+      - id: mypy
+  # run these occasionally, ref discussion https://github.com/pydata/xarray/pull/3194
+  # - repo: https://github.com/asottile/pyupgrade
+  #   rev: v1.22.1
+  #   hooks:
+  #     - id: pyupgrade
+  #       args:
+  #         - "--py3-only"
+  #         # remove on f-strings in Py3.7
+  #         - "--keep-percent-format"
+  # - repo: https://github.com/timothycrosley/isort
+  #   rev: 4.3.21-2
+  #   hooks:
+  #     - id: isort

README.rst

@@ -11,6 +11,9 @@ xarray: N-D labeled arrays and datasets
   :target: https://pandas.pydata.org/speed/xarray/
 .. image:: https://img.shields.io/pypi/v/xarray.svg
    :target: https://pypi.python.org/pypi/xarray/
+.. image:: https://img.shields.io/badge/code%20style-black-000000.svg
+    :target: https://github.com/python/black
+
 
 **xarray** (formerly **xray**) is an open source project and Python package
 that makes working with labelled multi-dimensional arrays simple,

asv_bench/benchmarks/__init__.py

@@ -1,5 +1,3 @@
-from __future__ import absolute_import, division, print_function
-
 import itertools
 
 import numpy as np
@@ -12,6 +10,7 @@ def decorator(func):
         func.param_names = names
         func.params = params
         return func
+
     return decorator
 
 
@@ -28,6 +27,7 @@ def randn(shape, frac_nan=None, chunks=None, seed=0):
         x = rng.standard_normal(shape)
     else:
         import dask.array as da
+
         rng = da.random.RandomState(seed)
         x = rng.standard_normal(shape, chunks=chunks)
 

asv_bench/benchmarks/combine.py

@@ -13,22 +13,22 @@ def setup(self):
         data = np.random.randn(t_size, x_size, y_size)
 
         self.dsA0 = xr.Dataset(
-            {'A': xr.DataArray(data, coords={'T': t},
-                               dims=('T', 'X', 'Y'))})
+            {"A": xr.DataArray(data, coords={"T": t}, dims=("T", "X", "Y"))}
+        )
         self.dsA1 = xr.Dataset(
-            {'A': xr.DataArray(data, coords={'T': t + t_size},
-                               dims=('T', 'X', 'Y'))})
+            {"A": xr.DataArray(data, coords={"T": t + t_size}, dims=("T", "X", "Y"))}
+        )
         self.dsB0 = xr.Dataset(
-            {'B': xr.DataArray(data, coords={'T': t},
-                               dims=('T', 'X', 'Y'))})
+            {"B": xr.DataArray(data, coords={"T": t}, dims=("T", "X", "Y"))}
+        )
         self.dsB1 = xr.Dataset(
-            {'B': xr.DataArray(data, coords={'T': t + t_size},
-                               dims=('T', 'X', 'Y'))})
+            {"B": xr.DataArray(data, coords={"T": t + t_size}, dims=("T", "X", "Y"))}
+        )
 
     def time_combine_manual(self):
         datasets = [[self.dsA0, self.dsA1], [self.dsB0, self.dsB1]]
 
-        xr.combine_manual(datasets, concat_dim=[None, 't'])
+        xr.combine_manual(datasets, concat_dim=[None, "t"])
 
     def time_auto_combine(self):
         """Also has to load and arrange t coordinate"""

asv_bench/benchmarks/dataarray_missing.py

@@ -1,5 +1,3 @@
-from __future__ import absolute_import, division, print_function
-
 import pandas as pd
 
 import xarray as xr
@@ -14,9 +12,8 @@
 
 def make_bench_data(shape, frac_nan, chunks):
     vals = randn(shape, frac_nan)
-    coords = {'time': pd.date_range('2000-01-01', freq='D',
-                                    periods=shape[0])}
-    da = xr.DataArray(vals, dims=('time', 'x', 'y'), coords=coords)
+    coords = {"time": pd.date_range("2000-01-01", freq="D", periods=shape[0])}
+    da = xr.DataArray(vals, dims=("time", "x", "y"), coords=coords)
 
     if chunks is not None:
         da = da.chunk(chunks)
@@ -28,44 +25,50 @@ def time_interpolate_na(shape, chunks, method, limit):
     if chunks is not None:
         requires_dask()
     da = make_bench_data(shape, 0.1, chunks=chunks)
-    actual = da.interpolate_na(dim='time', method='linear', limit=limit)
+    actual = da.interpolate_na(dim="time", method="linear", limit=limit)
 
     if chunks is not None:
         actual = actual.compute()
 
 
-time_interpolate_na.param_names = ['shape', 'chunks', 'method', 'limit']
-time_interpolate_na.params = ([(3650, 200, 400), (100, 25, 25)],
-                              [None, {'x': 25, 'y': 25}],
-                              ['linear', 'spline', 'quadratic', 'cubic'],
-                              [None, 3])
+time_interpolate_na.param_names = ["shape", "chunks", "method", "limit"]
+time_interpolate_na.params = (
+    [(3650, 200, 400), (100, 25, 25)],
+    [None, {"x": 25, "y": 25}],
+    ["linear", "spline", "quadratic", "cubic"],
+    [None, 3],
+)
 
 
 def time_ffill(shape, chunks, limit):
 
     da = make_bench_data(shape, 0.1, chunks=chunks)
-    actual = da.ffill(dim='time', limit=limit)
+    actual = da.ffill(dim="time", limit=limit)
 
     if chunks is not None:
         actual = actual.compute()
 
 
-time_ffill.param_names = ['shape', 'chunks', 'limit']
-time_ffill.params = ([(3650, 200, 400), (100, 25, 25)],
-                     [None, {'x': 25, 'y': 25}],
-                     [None, 3])
+time_ffill.param_names = ["shape", "chunks", "limit"]
+time_ffill.params = (
+    [(3650, 200, 400), (100, 25, 25)],
+    [None, {"x": 25, "y": 25}],
+    [None, 3],
+)
 
 
 def time_bfill(shape, chunks, limit):
 
     da = make_bench_data(shape, 0.1, chunks=chunks)
-    actual = da.bfill(dim='time', limit=limit)
+    actual = da.bfill(dim="time", limit=limit)
 
     if chunks is not None:
         actual = actual.compute()
 
 
-time_bfill.param_names = ['shape', 'chunks', 'limit']
-time_bfill.params = ([(3650, 200, 400), (100, 25, 25)],
-                     [None, {'x': 25, 'y': 25}],
-                     [None, 3])
+time_bfill.param_names = ["shape", "chunks", "limit"]
+time_bfill.params = (
+    [(3650, 200, 400), (100, 25, 25)],
+    [None, {"x": 25, "y": 25}],
+    [None, 3],
+)