Drop Python2 support. (#95)

* Remove python2 things from setup.json.

* Remove all `from __future__ ...` statements.

* Remove `modernizer` hook from the pre-commit config.

* Remove `six` and all the references in the code.

.ci/check_travis_tag.py

@@ -7,8 +7,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Check travis tag"""
-from __future__ import print_function
-from __future__ import absolute_import
 
 import os
 import sys

.pre-commit-config.yaml

@@ -1,17 +1,6 @@
 # # Install pre-commit hooks via
 # pre-commit install
 
-# modernizer: make sure our code-base is Python 3 ready
-- repo: https://github.com/python-modernize/python-modernize.git
-  sha: a234ce4e185cf77a55632888f1811d83b4ad9ef2
-  hooks:
-  - id: python-modernize
-    exclude: ^docs/
-    args:
-      - --write
-      - --nobackups
-      - --nofix=dict_six
-
 - repo: local
   hooks:
   # yapf = yet another python formatter

.pylintrc

@@ -273,10 +273,6 @@ ignored-argument-names=_.*|^ignored_|^unused_
 # Tells whether we should check for unused import in __init__ files.
 init-import=no
 
-# List of qualified module names which can have objects that can redefine
-# builtins.
-redefining-builtins-modules=six.moves,future.builtins
-
 
 [MISCELLANEOUS]
 

aiida_cp2k/calculations/__init__.py

@@ -7,11 +7,7 @@
 ###############################################################################
 """AiiDA-CP2K input plugin."""
 
-from __future__ import absolute_import
-
 import io
-import six
-from six.moves import map
 
 from aiida.engine import CalcJob
 from aiida.orm import Computer, Dict, SinglefileData, StructureData, RemoteData, BandsData
@@ -51,16 +47,13 @@ def define(cls, spec):
                              dynamic=True)
 
         # Specify default parser.
-        spec.input('metadata.options.parser_name',
-                   valid_type=six.string_types,
-                   default=cls._DEFAULT_PARSER,
-                   non_db=True)
+        spec.input('metadata.options.parser_name', valid_type=str, default=cls._DEFAULT_PARSER, non_db=True)
 
         # Add input_filename attribute.
-        spec.input('metadata.options.input_filename', valid_type=six.string_types, default=cls._DEFAULT_INPUT_FILE)
+        spec.input('metadata.options.input_filename', valid_type=str, default=cls._DEFAULT_INPUT_FILE)
 
         # Add output_filename attribute.
-        spec.input('metadata.options.output_filename', valid_type=six.string_types, default=cls._DEFAULT_OUTPUT_FILE)
+        spec.input('metadata.options.output_filename', valid_type=str, default=cls._DEFAULT_OUTPUT_FILE)
 
         # Use mpi by default.
         spec.input('metadata.options.withmpi', valid_type=bool, default=True)
@@ -129,7 +122,7 @@ def prepare_for_submission(self, folder):
             try:
                 fobj.write(inp.render())
             except ValueError as exc:
-                six.raise_from(InputValidationError("invalid keys or values in input parameters found"), exc)
+                raise InputValidationError("Invalid keys or values in input parameters found") from exc
 
         settings = self.inputs.settings.get_dict() if 'settings' in self.inputs else {}
 

aiida_cp2k/parsers/__init__.py

@@ -6,7 +6,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """AiiDA-CP2K output parser."""
-from __future__ import absolute_import
 
 import io
 import os

aiida_cp2k/utils/__init__.py

@@ -6,7 +6,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """AiiDA-CP2K utils"""
-from __future__ import absolute_import
 
 from .input_generator import Cp2kInput
 from .parser import parse_cp2k_output

aiida_cp2k/utils/input_generator.py

@@ -7,16 +7,9 @@
 ###############################################################################
 """AiiDA-CP2K input generator"""
 
-from __future__ import absolute_import
-from __future__ import division
-
 from copy import deepcopy
 
-import six
-if six.PY2:
-    from collections import Mapping, Sequence  # pylint: disable=import-error, no-name-in-module
-else:
-    from collections.abc import Mapping, Sequence  # pylint: disable=import-error, no-name-in-module
+from collections.abc import Mapping, Sequence
 
 
 class Cp2kInput:  # pylint: disable=old-style-class
@@ -55,7 +48,7 @@ def add_keyword(self, kwpath, value, override=True, conflicting_keys=None):
             added.
         """
 
-        if isinstance(kwpath, six.string_types):
+        if isinstance(kwpath, str):
             kwpath = kwpath.split("/")
 
         Cp2kInput._add_keyword(kwpath, value, self._params, ovrd=override, cfct=conflicting_keys)
@@ -89,7 +82,7 @@ def _add_keyword(kwpath, value, params, ovrd, cfct):
             Cp2kInput._add_keyword(kwpath[1:], value, params[kwpath[0]], ovrd, cfct)
 
         # if it is a list, loop over its elements
-        elif isinstance(params[kwpath[0]], Sequence) and not isinstance(params[kwpath[0]], six.string_types):
+        elif isinstance(params[kwpath[0]], Sequence) and not isinstance(params[kwpath[0]], str):
             for element in params[kwpath[0]]:
                 Cp2kInput._add_keyword(kwpath[1:], value, element, ovrd, cfct)
 
@@ -151,7 +144,7 @@ def _render_section(output, params, indent=0):
                 Cp2kInput._render_section(output, val, indent + 3)
                 output.append('{}&END {}'.format(' ' * indent, key))
 
-            elif isinstance(val, Sequence) and not isinstance(val, six.string_types):
+            elif isinstance(val, Sequence) and not isinstance(val, str):
                 for listitem in val:
                     Cp2kInput._render_section(output, {key: listitem}, indent)
 

aiida_cp2k/utils/parser.py

@@ -7,9 +7,6 @@
 ###############################################################################
 """AiiDA-CP2K input plugin."""
 
-from __future__ import absolute_import
-from __future__ import division
-
 import re
 import math
 

aiida_cp2k/utils/workchains.py

@@ -7,7 +7,6 @@
 ###############################################################################
 """AiiDA-CP2K utilities for workchains"""
 
-from __future__ import absolute_import
 from aiida.engine import calcfunction
 from aiida.orm import Dict, StructureData
 

aiida_cp2k/workchains/aiida_base_restart.py

@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 # pylint: disable=inconsistent-return-statements,no-member
 """Base implementation of `WorkChain` class that implements a simple automated restart mechanism for calculations."""
-from __future__ import absolute_import
 
 from collections import namedtuple
 

aiida_cp2k/workchains/base.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 """Base workchain to run a CP2K calculation"""
-from __future__ import absolute_import
 
 from aiida.common import AttributeDict
 from aiida.engine import while_

conftest.py

@@ -1,7 +1,6 @@
 """
 For pytest initialise a test database and profile
 """
-from __future__ import absolute_import
 import pytest
 pytest_plugins = ['aiida.manage.tests.pytest_fixtures']  # pylint: disable=invalid-name
 

examples/single_calculations/example_dft.py

@@ -8,9 +8,6 @@
 ###############################################################################
 """Run simple DFT calculation."""
 
-from __future__ import print_function
-from __future__ import absolute_import
-
 import os
 import sys
 import click

examples/single_calculations/example_dft_atomic_kinds.py

@@ -8,9 +8,6 @@
 ###############################################################################
 """Run DFT calculation with different atomic kinds."""
 
-from __future__ import print_function
-from __future__ import absolute_import
-
 import os
 import sys
 import click

examples/single_calculations/example_failure.py

@@ -7,8 +7,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Run failing calculation."""
-from __future__ import print_function
-from __future__ import absolute_import
 
 import sys
 import click

examples/single_calculations/example_geopt.py

@@ -7,8 +7,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Run DFT geometry optimization."""
-from __future__ import print_function
-from __future__ import absolute_import
 
 import os
 import sys

examples/single_calculations/example_mm.py

@@ -7,8 +7,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Run molecular mechanics calculation."""
-from __future__ import print_function
-from __future__ import absolute_import
 
 import os
 import sys

examples/single_calculations/example_multiple_force_eval.py

@@ -8,9 +8,6 @@
 ###############################################################################
 """Run DFT calculation with multiple force eval sections."""
 
-from __future__ import print_function
-from __future__ import absolute_import
-
 import os
 import sys
 import click

examples/single_calculations/example_no_struct.py

@@ -8,9 +8,6 @@
 ###############################################################################
 """Run DFT calculation with structure specified in the input file."""
 
-from __future__ import print_function
-from __future__ import absolute_import
-
 import os
 import sys
 import click

examples/single_calculations/example_precision.py

@@ -7,8 +7,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Test structure roundtrip precision ase->aiida->cp2k->aiida->ase."""
-from __future__ import print_function
-from __future__ import absolute_import
 
 import os
 import sys

examples/single_calculations/example_restart.py

@@ -7,8 +7,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Test CP2K restart."""
-from __future__ import print_function
-from __future__ import absolute_import
 
 import os
 import re

examples/single_calculations/example_structure_through_file.py

@@ -8,13 +8,9 @@
 ###############################################################################
 """Run simple DFT calculation"""
 
-from __future__ import print_function
-from __future__ import absolute_import
-
 import os
 import sys
 import click
-from six.moves import range
 
 import ase.io
 

examples/single_calculations/fixme_bands.py

@@ -8,9 +8,6 @@
 ###############################################################################
 """Run simple Band Structure calculation"""
 
-from __future__ import print_function
-from __future__ import absolute_import
-
 import os
 import sys
 import click

examples/workchains/example_base.py

@@ -8,9 +8,6 @@
 ###############################################################################
 """Run simple DFT calculation through a workchain."""
 
-from __future__ import print_function
-from __future__ import absolute_import
-
 import os
 import sys
 import ase.io

setup.json

@@ -7,15 +7,12 @@
         "License :: OSI Approved :: MIT License",
         "Operating System :: POSIX :: Linux",
         "Operating System :: MacOS :: MacOS X",
-        "Programming Language :: Python :: 2.7",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7"
+        "Programming Language :: Python :: 3"
     ],
     "description": "The official AiiDA plugin for CP2K.",
     "install_requires": [
-        "aiida-core>=1.0.0,<1.1.0",
-        "ase==3.17.0; python_version<'3.0'",
-        "ase; python_version>='3.5'",
+        "aiida-core>=1.1.0,<2.0.0",
+        "ase",
         "ruamel.yaml>=0.16.5"
     ],
     "entry_points": {
@@ -31,25 +28,24 @@
         ]
     },
     "extras_require": {
-    	"test": [
-    	    "pgtest==1.2.0",
-    	    "pytest>=4.4,<5.0.0",
-    	    "pytest-cov>=2.6.1,<3.0.0",
-    	    "coverage"
-    	],
-    	"pre-commit":[
-    	    "pre-commit==1.18.3",
-    	    "yapf==0.28.0",
-    	    "prospector==1.1.7",
-    	    "pylint==1.9.4; python_version<'3.0'",
-    	    "pylint==2.3.1; python_version>='3.0'"
-    	],
-    	"docs": [
-    	    "sphinx",
-    	    "sphinx-rtd-theme",
-    	    "sphinxcontrib-contentui",
-    	    "sphinxcontrib-details-directive; python_version>='3.0'"
-    	]
+        "test": [
+            "pgtest==1.2.0",
+            "pytest>=4.4,<5.0.0",
+            "pytest-cov>=2.6.1,<3.0.0",
+            "coverage"
+        ],
+        "pre-commit":[
+            "pre-commit==1.18.3",
+            "yapf==0.28.0",
+            "prospector==1.1.7",
+            "pylint==2.3.1"
+        ],
+        "docs": [
+            "sphinx",
+            "sphinx-rtd-theme",
+            "sphinxcontrib-contentui",
+            "sphinxcontrib-details-directive"
+        ]
     },
     "license": "MIT License",
     "name": "aiida_cp2k",

setup.py

@@ -6,7 +6,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Setting up CP2K plugin for AiiDA"""
-from __future__ import absolute_import
 
 import json
 

test/test_input_generator.py

@@ -7,8 +7,6 @@
 ###############################################################################
 """Test Cp2k input generator"""
 
-from __future__ import absolute_import
-
 import pytest
 
 from aiida_cp2k.utils import Cp2kInput

test/test_version_agreement.py

@@ -6,8 +6,6 @@
 # For further information on the license, see the LICENSE.txt file.           #
 ###############################################################################
 """Check versions"""
-from __future__ import print_function
-from __future__ import absolute_import
 
 import sys
 import json