Drop dependency on Setuptools (#4443)

Instead of relying on `setuptools` to get functionality from
`pkg_resources` (which is slowly being refactored away), leverage
`packaging` for the functionality used by Conda-Build.

Co-authored-by: Jannis Leidel <jannis@leidel.info>

.pre-commit-config.yaml

@@ -73,3 +73,4 @@ repos:
       - id: insert-license
         files: \.py$
         args: [--license-filepath, .github/disclaimer.txt, --no-extra-eol]
+        exclude: ^conda_build/version.py

conda_build/skeletons/cpan.py

@@ -7,7 +7,6 @@
 
 import codecs
 import hashlib
-from pkg_resources import parse_version
 from glob import glob
 import gzip
 import json
@@ -28,6 +27,7 @@
 from conda_build.config import get_or_merge_config
 from conda_build.utils import on_win, check_call_env
 from conda_build.variants import get_default_variant
+from conda_build.version import _parse as parse_version
 
 import requests
 from conda_build import environ

conda_build/skeletons/pypi.py

@@ -12,7 +12,7 @@
 from os import makedirs, listdir, getcwd, chdir
 from os.path import join, isdir, exists, isfile, abspath
 
-from pkg_resources import parse_version
+from conda_build.version import _parse as parse_version
 import re
 from shutil import copy2
 import subprocess

conda_build/variants.py

@@ -8,14 +8,14 @@
 from functools import lru_cache
 from itertools import product
 import os.path
-from pkg_resources import parse_version
 import re
 import sys
 
 import yaml
 
 from conda_build.conda_interface import subdir
 from conda_build.conda_interface import cc_conda_build
+from conda_build.version import _parse as parse_version
 from conda_build.utils import ensure_list, get_logger, islist, on_win, trim_empty_keys
 
 DEFAULT_VARIANTS = {

conda_build/version.py

@@ -0,0 +1,160 @@
+# Copyright (C) Donald Stufft and individual contributors
+# SPDX-License-Identifier: BSD-2-Clause
+"""
+This file was partially copied from the packaging.version module before the
+LegacyVersion class was removed to continue to support version parsing in
+a backward-compatible way where PEP 440 support can't be used.
+
+Copyright (c) Donald Stufft and individual contributors.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+"""
+import re
+from typing import Iterator, List, Tuple, Union
+from packaging.version import _BaseVersion, Version, InvalidVersion
+
+LegacyCmpKey = Tuple[int, Tuple[str, ...]]
+
+
+def _parse(version: str) -> Union["_LegacyVersion", "Version"]:
+    """
+    Parse the given version string and return either a :class:`Version` object
+    or a :class:`_LegacyVersion` object depending on if the given version is
+    a valid PEP 440 version or a legacy version.
+    """
+    try:
+        return Version(version)
+    except InvalidVersion:
+        return _LegacyVersion(version)
+
+
+class _LegacyVersion(_BaseVersion):
+
+    def __init__(self, version: str) -> None:
+        self._version = str(version)
+        self._key = _legacy_cmpkey(self._version)
+
+    def __str__(self) -> str:
+        return self._version
+
+    def __repr__(self) -> str:
+        return f"<_LegacyVersion('{self}')>"
+
+    @property
+    def public(self) -> str:
+        return self._version
+
+    @property
+    def base_version(self) -> str:
+        return self._version
+
+    @property
+    def epoch(self) -> int:
+        return -1
+
+    @property
+    def release(self) -> None:
+        return None
+
+    @property
+    def pre(self) -> None:
+        return None
+
+    @property
+    def post(self) -> None:
+        return None
+
+    @property
+    def dev(self) -> None:
+        return None
+
+    @property
+    def local(self) -> None:
+        return None
+
+    @property
+    def is_prerelease(self) -> bool:
+        return False
+
+    @property
+    def is_postrelease(self) -> bool:
+        return False
+
+    @property
+    def is_devrelease(self) -> bool:
+        return False
+
+
+_legacy_version_component_re = re.compile(r"(\d+ | [a-z]+ | \.| -)", re.VERBOSE)
+
+_legacy_version_replacement_map = {
+    "pre": "c",
+    "preview": "c",
+    "-": "final-",
+    "rc": "c",
+    "dev": "@",
+}
+
+
+def _parse_version_parts(s: str) -> Iterator[str]:
+    for part in _legacy_version_component_re.split(s):
+        part = _legacy_version_replacement_map.get(part, part)
+
+        if not part or part == ".":
+            continue
+
+        if part[:1] in "0123456789":
+            # pad for numeric comparison
+            yield part.zfill(8)
+        else:
+            yield "*" + part
+
+    # ensure that alpha/beta/candidate are before final
+    yield "*final"
+
+
+def _legacy_cmpkey(version: str) -> LegacyCmpKey:
+
+    # We hardcode an epoch of -1 here. A PEP 440 version can only have a epoch
+    # greater than or equal to 0. This will effectively put the LegacyVersion,
+    # which uses the defacto standard originally implemented by setuptools,
+    # as before all PEP 440 versions.
+    epoch = -1
+
+    # This scheme is taken from pkg_resources.parse_version setuptools prior to
+    # it's adoption of the packaging library.
+    parts: List[str] = []
+    for part in _parse_version_parts(version.lower()):
+        if part.startswith("*"):
+            # remove "-" before a prerelease tag
+            if part < "*final":
+                while parts and parts[-1] == "*final-":
+                    parts.pop()
+
+            # remove trailing zeros from each series of numeric parts
+            while parts and parts[-1] == "00000000":
+                parts.pop()
+
+        parts.append(part)
+
+    return epoch, tuple(parts)

recipe/meta.yaml

@@ -34,6 +34,7 @@ requirements:
     - filelock
     - futures       # [py<3]
     - jinja2
+    - packaging
     - patchelf      # [linux]
     - patch     >=2.6   # [not win]
     - m2-patch  >=2.6   # [win]
@@ -44,7 +45,6 @@ requirements:
     - pyyaml
     - requests
     - scandir       # [py<34]
-    - setuptools
     - six
     - glob2  >=0.6
     - pytz

setup.py

@@ -26,7 +26,7 @@
     "psutil",
     "six",
     "libarchive-c",
-    "setuptools",
+    "packaging",
     # "conda-package-handling",  # remove comment once released on PyPI
     "glob2",
 ]

tests/test_api_skeleton.py

@@ -7,7 +7,7 @@
 import subprocess
 import sys
 
-from pkg_resources import parse_version
+from conda_build.version import _parse as parse_version
 import pytest
 import ruamel.yaml