Skip some uses of packaging's PEP440 version for non-Python versions.

Version numbers from non-Python packages don't have to follow PEP440,
and there are at least a few cases where we can check for string
equality (when we don't need ordering) or rely on the library's own
version parsing (qt).

Author: anntzer

lib/matplotlib/__init__.py

@@ -278,7 +278,7 @@ def wrapper(**kwargs):
     return wrapper
 
 
-_ExecInfo = namedtuple("_ExecInfo", "executable version")
+_ExecInfo = namedtuple("_ExecInfo", "executable raw_version version")
 
 
 class ExecutableNotFoundError(FileNotFoundError):
@@ -339,12 +339,13 @@ def impl(args, regex, min_ver=None, ignore_exit_code=False):
             raise ExecutableNotFoundError(str(_ose)) from _ose
         match = re.search(regex, output)
         if match:
-            version = parse_version(match.group(1))
+            raw_version = match.group(1)
+            version = parse_version(raw_version)
             if min_ver is not None and version < parse_version(min_ver):
                 raise ExecutableNotFoundError(
                     f"You have {args[0]} version {version} but the minimum "
                     f"version supported by Matplotlib is {min_ver}")
-            return _ExecInfo(args[0], version)
+            return _ExecInfo(args[0], raw_version, version)
         else:
             raise ExecutableNotFoundError(
                 f"Failed to determine the version of {args[0]} from "
@@ -401,7 +402,7 @@ def impl(args, regex, min_ver=None, ignore_exit_code=False):
         else:
             path = "convert"
         info = impl([path, "--version"], r"^Version: ImageMagick (\S*)")
-        if info.version == parse_version("7.0.10-34"):
+        if info.raw_version == "7.0.10-34":
             # https://github.com/ImageMagick/ImageMagick/issues/2720
             raise ExecutableNotFoundError(
                 f"You have ImageMagick {info.version}, which is unsupported")

lib/matplotlib/backends/qt_compat.py

@@ -134,9 +134,8 @@ def _isdeleted(obj):
 # https://bugreports.qt.io/browse/QTBUG-87014, fixed in qt 5.15.2
 if (sys.platform == 'darwin' and
         parse_version(platform.mac_ver()[0]) >= parse_version("10.16") and
-        parse_version(QtCore.qVersion()) < parse_version("5.15.2") and
-        "QT_MAC_WANTS_LAYER" not in os.environ):
-    os.environ["QT_MAC_WANTS_LAYER"] = "1"
+        QtCore.QLibraryInfo.version().segments() <= [5, 15, 2]):
+    os.environ.setdefault("QT_MAC_WANTS_LAYER", "1")
 
 
 # PyQt6 enum compat helpers.

lib/matplotlib/texmanager.py

@@ -29,7 +29,6 @@
 from tempfile import TemporaryDirectory
 
 import numpy as np
-from packaging.version import parse as parse_version
 
 import matplotlib as mpl
 from matplotlib import _api, cbook, dviread, rcParams
@@ -291,9 +290,8 @@ def make_png(self, tex, fontsize, dpi):
             # dvipng 1.16 has a bug (fixed in f3ff241) that breaks --freetype0
             # mode, so for it we keep FreeType enabled; the image will be
             # slightly off.
-            bad_ver = parse_version("1.16")
-            if (getattr(mpl, "_called_from_pytest", False)
-                    and mpl._get_executable_info("dvipng").version != bad_ver):
+            if (getattr(mpl, "_called_from_pytest", False) and
+                    mpl._get_executable_info("dvipng").raw_version != "1.16"):
                 cmd.insert(1, "--freetype0")
             self._run_checked_subprocess(cmd, tex)
         return pngfile