Drop Python 2 compat code and bump support to >=3.7 (holoviz#1033)

* require python >= 3.7
* add classifiers for pypi
* remove references to Python 2 in the docs
* remove python 2 compat
* remove py27 env from tox
* cleanup and drop 3.6
* Run the CI on py3.9
* add badge of supported versions in the README

.coveragerc

@@ -1,6 +1,5 @@
 [run]
 omit =
     */test_*.py
-    datashader/compatibility.py
 source =
     datashader

.github/workflows/test.yaml

@@ -6,6 +6,7 @@ on:
   pull_request:
     branches:
     - '*'
+  workflow_dispatch:
 
 jobs:
   test_suite:
@@ -54,12 +55,6 @@ jobs:
           eval "$(conda shell.bash hook)"
           conda activate test-environment
           doit develop_install -o tests -o examples --conda-mode=mamba
-      - name: Python 3.6 installs
-        if: matrix.python-version == '3.6'
-        run: |
-          eval "$(conda shell.bash hook)"
-          conda activate test-environment
-          mamba install "panel=0.12" dataclasses
       - name: patch for fiona on windows / 3.7 
         if: matrix.os == 'windows-latest' && matrix.python-version == '3.7'
         run: |
@@ -76,11 +71,11 @@ jobs:
           eval "$(conda shell.bash hook)"
           conda activate test-environment
           doit test_lint
-      - name: doit test_unit_deploy
+      - name: doit test_unit
         run: |
           eval "$(conda shell.bash hook)"
           conda activate test-environment
-          doit test_unit_deploy
+          doit test_unit
       - name: doit test_unit_nojit
         run: |
           eval "$(conda shell.bash hook)"

README.md

@@ -10,6 +10,7 @@
 | Coverage | [![codecov](https://codecov.io/gh/holoviz/datashader/branch/master/graph/badge.svg)](https://codecov.io/gh/holoviz/datashader) |
 | Latest dev release | [![Github tag](https://img.shields.io/github/tag/holoviz/datashader.svg?label=tag&colorB=11ccbb)](https://github.com/holoviz/datashader/tags) [![dev-site](https://img.shields.io/website-up-down-green-red/https/pyviz-dev.github.io/datashader.svg?label=dev%20website)](https://pyviz-dev.github.io/datashader/) |
 | Latest release | [![Github release](https://img.shields.io/github/release/holoviz/datashader.svg?label=tag&colorB=11ccbb)](https://github.com/holoviz/datashader/releases) [![PyPI version](https://img.shields.io/pypi/v/datashader.svg?colorB=cc77dd)](https://pypi.python.org/pypi/datashader) [![datashader version](https://img.shields.io/conda/v/pyviz/datashader.svg?colorB=4488ff&style=flat)](https://anaconda.org/pyviz/datashader) [![conda-forge version](https://img.shields.io/conda/v/conda-forge/datashader.svg?label=conda%7Cconda-forge&colorB=4488ff)](https://anaconda.org/conda-forge/datashader) [![defaults version](https://img.shields.io/conda/v/anaconda/datashader.svg?label=conda%7Cdefaults&style=flat&colorB=4488ff)](https://anaconda.org/anaconda/datashader) |
+| Python | [![Python support](https://img.shields.io/pypi/pyversions/datashader.svg)](https://pypi.org/project/datashader/)
 | Docs | [![gh-pages](https://img.shields.io/github/last-commit/holoviz/datashader/gh-pages.svg)](https://github.com/holoviz/datashader/tree/gh-pages) [![site](https://img.shields.io/website-up-down-green-red/http/datashader.org.svg)](http://datashader.org) |
 | Support | [![Discourse](https://img.shields.io/discourse/status?server=https%3A%2F%2Fdiscourse.holoviz.org)](https://discourse.holoviz.org/) |
 
@@ -48,7 +49,7 @@ to work with much larger datasets than it would otherwise.
 
 ## Installation
 
-Datashader supports Python 2.7, 3.6 and 3.7 on Linux, Windows, or
+Datashader supports Python 3.7, 3.8, 3.9 and 3.10 on Linux, Windows, or
 Mac and can be installed with conda:
 
     conda install datashader

datashader/colors.py

@@ -1,11 +1,5 @@
 from __future__ import absolute_import, division, print_function
 
-# Declare Python2/3 unicode-safe string type
-try:
-      basestring
-except NameError:
-      basestring = str
-
 
 # Lookup of web color names to their hex codes.
 color_lookup = {'aliceblue': '#F0F8FF', 'antiquewhite': '#FAEBD7',
@@ -117,7 +111,7 @@ def rgb(x):
     >>> rgb((255, 255, 255))
     (255, 255, 255)
     """
-    if isinstance(x, basestring):
+    if isinstance(x, str):
         if x.startswith('#'):
             return hex_to_rgb(x)
         elif x in color_lookup:

datashader/compiler.py

@@ -6,7 +6,6 @@
 import numpy as np
 import xarray as xr
 
-from .compatibility import _exec
 from .reductions import by, category_codes, summary
 from .utils import ngjit
 
@@ -148,7 +147,7 @@ def make_append(bases, cols, calls, glyph, categorical):
         code = ('def append({0}, x, y, {1}):\n'
                 '    {2}'
                 ).format(subscript, ', '.join(signature), '\n    '.join(body))
-    _exec(code, namespace)
+    exec(code, namespace)
     return ngjit(namespace['append'])
 
 

datashader/core.py

@@ -7,7 +7,6 @@
 import pandas as pd
 import dask.dataframe as dd
 import dask.array as da
-from six import string_types
 from xarray import DataArray, Dataset
 from collections import OrderedDict
 
@@ -376,8 +375,8 @@ def line(self, source, x=None, y=None, agg=None, axis=0, geometry=None,
             x, y = _broadcast_column_specifications(x, y)
 
             if axis == 0:
-                if (isinstance(x, (Number, string_types)) and
-                        isinstance(y, (Number, string_types))):
+                if (isinstance(x, (Number, str)) and
+                        isinstance(y, (Number, str))):
                     glyph = LineAxis0(x, y)
                 elif (isinstance(x, (list, tuple)) and
                         isinstance(y, (list, tuple))):
@@ -400,8 +399,8 @@ def line(self, source, x=None, y=None, agg=None, axis=0, geometry=None,
                 elif (isinstance(x, (list, tuple)) and
                       isinstance(y, np.ndarray)):
                     glyph = LinesAxis1YConstant(tuple(x), y)
-                elif (isinstance(x, (Number, string_types)) and
-                        isinstance(y, (Number, string_types))):
+                elif (isinstance(x, (Number, str)) and
+                        isinstance(y, (Number, str))):
                     glyph = LinesAxis1Ragged(x, y)
                 else:
                     raise ValueError("""
@@ -591,8 +590,8 @@ def area(self, source, x, y, agg=None, axis=0, y_stack=None):
 
         if axis == 0:
             if y_stack is None:
-                if (isinstance(x, (Number, string_types)) and
-                        isinstance(y, (Number, string_types))):
+                if (isinstance(x, (Number, str)) and
+                        isinstance(y, (Number, str))):
                     glyph = AreaToZeroAxis0(x, y)
                 elif (isinstance(x, (list, tuple)) and
                       isinstance(y, (list, tuple))):
@@ -607,9 +606,9 @@ def area(self, source, x, y, agg=None, axis=0, y_stack=None):
                         x=repr(x), y=repr(y)))
             else:
                 # y_stack is not None
-                if (isinstance(x, (Number, string_types)) and
-                        isinstance(y, (Number, string_types)) and
-                        isinstance(y_stack, (Number, string_types))):
+                if (isinstance(x, (Number, str)) and
+                        isinstance(y, (Number, str)) and
+                        isinstance(y_stack, (Number, str))):
 
                     glyph = AreaToLineAxis0(x, y, y_stack)
                 elif (isinstance(x, (list, tuple)) and
@@ -640,8 +639,8 @@ def area(self, source, x, y, agg=None, axis=0, y_stack=None):
                 elif (isinstance(x, (list, tuple)) and
                       isinstance(y, np.ndarray)):
                     glyph = AreaToZeroAxis1YConstant(tuple(x), y)
-                elif (isinstance(x, (Number, string_types)) and
-                      isinstance(y, (Number, string_types))):
+                elif (isinstance(x, (Number, str)) and
+                      isinstance(y, (Number, str))):
                     glyph = AreaToZeroAxis1Ragged(x, y)
                 else:
                     raise ValueError("""
@@ -666,9 +665,9 @@ def area(self, source, x, y, agg=None, axis=0, y_stack=None):
                       isinstance(y, np.ndarray) and
                       isinstance(y_stack, np.ndarray)):
                     glyph = AreaToLineAxis1YConstant(tuple(x), y, y_stack)
-                elif (isinstance(x, (Number, string_types)) and
-                      isinstance(y, (Number, string_types)) and
-                      isinstance(y_stack, (Number, string_types))):
+                elif (isinstance(x, (Number, str)) and
+                      isinstance(y, (Number, str)) and
+                      isinstance(y_stack, (Number, str))):
                     glyph = AreaToLineAxis1Ragged(x, y, y_stack)
                 else:
                     raise ValueError("""
@@ -1310,7 +1309,7 @@ def _broadcast_column_specifications(*args):
     else:
         n = lengths.pop()
         return tuple(
-            (arg,) * n if isinstance(arg, (Number, string_types)) else arg
+            (arg,) * n if isinstance(arg, (Number, str)) else arg
             for arg in args
         )
 

datashader/data_libraries/dask.py

@@ -9,7 +9,7 @@
 from dask.base import tokenize, compute
 
 from datashader.core import bypixel
-from datashader.compatibility import apply
+from datashader.utils import apply
 from datashader.compiler import compile_components
 from datashader.glyphs import Glyph, LineAxis0
 from datashader.utils import Dispatcher

datashader/data_libraries/dask_xarray.py

@@ -4,7 +4,7 @@
 from datashader.glyphs.quadmesh import (
     QuadMeshRaster, QuadMeshRectilinear, QuadMeshCurvilinear, build_scale_translate
 )
-from datashader.compatibility import apply
+from datashader.utils import apply
 import dask
 import numpy as np
 import xarray as xr

datashader/macros.py

@@ -86,18 +86,6 @@ def visit_Starred(self, node):
             return node
 
 
-class ExpandVarargTransformerCallArg(ExpandVarargTransformer):
-    # Python 2
-    def visit_Call(self, node):
-        if getattr(node, 'starargs', None) and node.starargs.id == self.starred_name:
-            node.starargs = None
-            node.args.extend([ast.Name(id=name, ctx=ast.Load())
-                              for name in self.expand_names])
-            return node
-        else:
-            return node
-
-
 def function_to_ast(fn):
     """
     Get the AST representation of a function
@@ -161,12 +149,7 @@ def function_ast_to_function(fn_ast, stacklevel=1):
 
 
 def _build_arg(name):
-    try:
-        # Python 3
-        return ast.arg(arg=name)
-    except AttributeError:
-        # Python 2
-        return ast.Name(id=name, ctx=ast.Param())
+    return ast.arg(arg=name)
 
 
 def expand_function_ast_varargs(fn_ast, expand_number):
@@ -238,12 +221,7 @@ def my_fn1(a, b, _0, _1, _2):
     expand_names = before_name_visitor.get_new_names(expand_number)
 
     # Replace use of *args in function body
-    if hasattr(ast, "Starred"):
-        # Python 3
-        expand_transformer = ExpandVarargTransformerStarred
-    else:
-        # Python 2
-        expand_transformer = ExpandVarargTransformerCallArg
+    expand_transformer = ExpandVarargTransformerStarred
 
     new_fn_ast = expand_transformer(
         vararg_name, expand_names

datashader/resampling.py

@@ -26,8 +26,6 @@
 
 from __future__ import absolute_import, division, print_function
 
-import sys
-import datetime as dt
 from itertools import groupby
 from math import floor, ceil
 
@@ -967,9 +965,6 @@ def infer_interval_breaks(coord, axis=0):
         pass
     else:
         coord = np.asarray(coord)
-    if sys.version_info.major == 2 and len(coord) and isinstance(coord[0], (dt.datetime, dt.date)):
-        # np.diff does not work on datetimes in python 2
-        coord = coord.astype('datetime64')
     if len(coord) == 0:
         return np.array([], dtype=coord.dtype)
     deltas = 0.5 * np.diff(coord, axis=axis)

datashader/tests/benchmarks/test_draw_line.py

@@ -1,7 +1,5 @@
 from __future__ import division
 
-import sys
-
 import pytest
 
 import numpy as np
@@ -11,9 +9,6 @@
     _build_map_onto_pixel_for_line, AntialiasCombination
 from datashader.utils import ngjit
 
-py2_skip = pytest.mark.skipif(sys.version_info.major < 3, reason="py2 not supported")
-
-
 mapper = ngjit(lambda x: x)
 map_onto_pixel = _build_map_onto_pixel_for_line(mapper, mapper)
 sx, tx, sy, ty = 1, 0, 1, 0
@@ -31,7 +26,6 @@ def append(i, x, y, agg):
                                False, AntialiasCombination.NONE)
 
 
-@py2_skip
 @pytest.mark.benchmark(group="draw_line")
 def test_draw_line_left_border(benchmark, draw_line):
     n = 10**4
@@ -43,7 +37,6 @@ def test_draw_line_left_border(benchmark, draw_line):
               x0, x1, y0, y1, 0.0, 0.0, agg)
 
 
-@py2_skip
 @pytest.mark.benchmark(group="draw_line")
 def test_draw_line_diagonal(benchmark, draw_line):
     n = 10**4
@@ -55,7 +48,6 @@ def test_draw_line_diagonal(benchmark, draw_line):
               x0, x1, y0, y1, 0.0, 0.0, agg)
 
 
-@py2_skip
 @pytest.mark.benchmark(group="draw_line")
 def test_draw_line_offset(benchmark, draw_line):
     n = 10**4

datashader/tests/benchmarks/test_extend_line.py

@@ -1,5 +1,3 @@
-import sys
-
 import numpy as np
 import pytest
 
@@ -10,8 +8,6 @@
 )
 from datashader.utils import ngjit
 
-py2_skip = pytest.mark.skipif(sys.version_info.major < 3, reason="py2 not supported")
-
 
 @pytest.fixture
 def extend_line():
@@ -27,7 +23,6 @@ def append(i, x, y, agg):
     return _build_extend_line_axis0(draw_line, expand_aggs_and_cols, AntialiasCombination.NONE)[0]
 
 
-@py2_skip
 @pytest.mark.parametrize('high', [0, 10**5])
 @pytest.mark.parametrize('low', [0, -10**5])
 @pytest.mark.benchmark(group="extend_line")
@@ -45,7 +40,6 @@ def test_extend_line_uniform(benchmark, extend_line, low, high):
     )
 
 
-@py2_skip
 @pytest.mark.benchmark(group="extend_line")
 def test_extend_line_normal(benchmark, extend_line):
     n = 10**6

datashader/tests/test_antialias.py

@@ -121,16 +121,13 @@
 
 
 import os
-import sys
 
 import xarray as xr
 import datashader as ds
 import pandas as pd
 import numpy as np
 import pytest
 
-if sys.version_info.major < 3:
-    pytestmark = pytest.mark.skip('Anti-aliasing not supported in python 2.')
 
 cm = pytest.importorskip('matplotlib.cm')
 binary = cm.binary