Drop support for Python 3.7

It's EOL as of June 27.  Debian oldstable has 3.9, Ubuntu 20.04 has 3.8,
RHEL 9 has 3.9, and RHEL 8 has 3.6 by default but 3.8+ available from
appstream.

This lets us drop the PATH workaround for Windows.

Signed-off-by: Benjamin Gilbert <bgilbert@cs.cmu.edu>

Author: bgilbert

.github/workflows/python.yml

@@ -30,7 +30,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        python-version: [3.7, 3.8, 3.9, "3.10", "3.11"]
+        python-version: [3.8, 3.9, "3.10", "3.11"]
     steps:
     - name: Check out repo
       uses: actions/checkout@v3
@@ -69,7 +69,7 @@ jobs:
         shell: bash
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10", "3.11"]
+        python-version: [3.8, 3.9, "3.10", "3.11"]
         python-arch: [x86, x64]
     steps:
     - name: Check out repo

README.md

@@ -37,7 +37,7 @@ OpenSlide can read virtual slides in several formats:
 
 ## Requirements
 
-* Python ≥ 3.7
+* Python ≥ 3.8
 * OpenSlide ≥ 3.4.0
 * Pillow
 

doc/index.rst

@@ -63,15 +63,12 @@ to a known path.  Then, import ``openslide`` inside a
 
     import os
     if hasattr(os, 'add_dll_directory'):
-        # Python >= 3.8 on Windows
+        # Windows
         with os.add_dll_directory(OPENSLIDE_PATH):
             import openslide
     else:
         import openslide
 
-This won't work with Python 3.7 or earlier; you'll need to add the OpenSlide
-``bin`` directory to your ``PATH`` instead.
-
 .. _install: https://openslide.org/download/#distribution-packages
 .. _Anaconda: https://anaconda.org/
 .. _MacPorts: https://www.macports.org/

examples/deepzoom/deepzoom_multiserver.py

@@ -30,17 +30,8 @@
 if os.name == 'nt':
     _dll_path = os.getenv('OPENSLIDE_PATH')
     if _dll_path is not None:
-        if hasattr(os, 'add_dll_directory'):
-            # Python >= 3.8
-            with os.add_dll_directory(_dll_path):
-                import openslide
-        else:
-            # Python < 3.8
-            _orig_path = os.environ.get('PATH', '')
-            os.environ['PATH'] = _orig_path + ';' + _dll_path
+        with os.add_dll_directory(_dll_path):
             import openslide
-
-            os.environ['PATH'] = _orig_path
     else:
         import openslide
 else:

examples/deepzoom/deepzoom_server.py

@@ -29,17 +29,8 @@
 if os.name == 'nt':
     _dll_path = os.getenv('OPENSLIDE_PATH')
     if _dll_path is not None:
-        if hasattr(os, 'add_dll_directory'):
-            # Python >= 3.8
-            with os.add_dll_directory(_dll_path):
-                import openslide
-        else:
-            # Python < 3.8
-            _orig_path = os.environ.get('PATH', '')
-            os.environ['PATH'] = _orig_path + ';' + _dll_path
+        with os.add_dll_directory(_dll_path):
             import openslide
-
-            os.environ['PATH'] = _orig_path
     else:
         import openslide
 else:

examples/deepzoom/deepzoom_tile.py

@@ -33,17 +33,8 @@
 if os.name == 'nt':
     _dll_path = os.getenv('OPENSLIDE_PATH')
     if _dll_path is not None:
-        if hasattr(os, 'add_dll_directory'):
-            # Python >= 3.8
-            with os.add_dll_directory(_dll_path):
-                import openslide
-        else:
-            # Python < 3.8
-            _orig_path = os.environ.get('PATH', '')
-            os.environ['PATH'] = _orig_path + ';' + _dll_path
+        with os.add_dll_directory(_dll_path):
             import openslide
-
-            os.environ['PATH'] = _orig_path
     else:
         import openslide
 else:

openslide/lowlevel.py

@@ -63,15 +63,9 @@ def try_load(names):
         try:
             return try_load(['libopenslide-1.dll', 'libopenslide-0.dll'])
         except FileNotFoundError:
-            import os
-
-            if hasattr(os, 'add_dll_directory'):
-                # Python >= 3.8
-                admonition = 'Did you call os.add_dll_directory()?'
-            else:
-                admonition = 'Did you add OpenSlide to PATH?'
             raise ModuleNotFoundError(
-                f"Couldn't locate OpenSlide DLL.  {admonition}  "
+                "Couldn't locate OpenSlide DLL.  "
+                "Did you call os.add_dll_directory()?  "
                 "https://openslide.org/api/python/#installing"
             )
     elif platform.system() == 'Darwin':

setup.py

@@ -39,14 +39,13 @@
         'Operating System :: POSIX :: Linux',
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: 3.11',
         'Topic :: Scientific/Engineering :: Bio-Informatics',
     ],
-    python_requires='>=3.7',
+    python_requires='>=3.8',
     install_requires=[
         'Pillow',
     ],

tests/common.py

@@ -28,18 +28,9 @@
     # environment.
     _dll_path = os.getenv('OPENSLIDE_PATH')
     if _dll_path is not None:
-        if hasattr(os, 'add_dll_directory'):
-            # Python >= 3.8
-            with os.add_dll_directory(_dll_path):
-                import openslide
-        else:
-            # Python < 3.8
-            _orig_path = os.environ.get('PATH', '')
-            os.environ['PATH'] = _orig_path + ';' + _dll_path
+        with os.add_dll_directory(_dll_path):
             import openslide  # noqa: F401  module-imported-but-unused
 
-            os.environ['PATH'] = _orig_path
-
 
 def file_path(name):
     return Path(__file__).parent / 'fixtures' / name