Use walrus more

It was already used in other places, so this doesn't change much.
Walrus was added in 3.8, so drop 3.7 from the compat list.

rust2rpm/__main__.py

@@ -62,8 +62,7 @@ def read_os_release():
         line = line.rstrip()
         if not line or line.startswith('#'):
             continue
-        m = re.match(r'([A-Z][A-Z_0-9]+)=(.*)', line)
-        if m:
+        if m := re.match(r'([A-Z][A-Z_0-9]+)=(.*)', line):
             name, val = m.groups()
             if val and val[0] in '"\'':
                 val = ast.literal_eval(val)
@@ -517,9 +516,7 @@ def main():
 
     if args.target in {"fedora"} and args.existence_check and not os.path.exists(spec_file):
         # No specfile, so this is probably a new package
-        package_info = get_package_info(pkg_name)
-
-        if package_info:
+        if package_info := get_package_info(pkg_name):
             if args.suffix:
                 print(f"Versions {args.suffix}.* of the crate '{metadata.name}' are already")
                 print(f"packaged for Fedora: {package_info['full_url']}")

rust2rpm/util.py

@@ -54,13 +54,11 @@ def detect_packager():
         return packager
 
     # If we're detecting packager identity through rpmdev-packager...
-    rpmdev_packager = shutil.which('rpmdev-packager')
-    if rpmdev_packager is not None:
+    if rpmdev_packager := shutil.which('rpmdev-packager'):
         return subprocess.check_output(rpmdev_packager, text=True).strip()
 
     # If we're detecting packager identity through git configuration...
-    git = shutil.which('git')
-    if git is not None:
+    if git := shutil.which('git'):
         name = subprocess.check_output([git, 'config', 'user.name'], text=True).strip()
         email = subprocess.check_output([git, 'config', 'user.email'], text=True).strip()
         return f'{name} <{email}>'

setup.py

@@ -49,7 +49,6 @@ ARGS = dict(
         "License :: OSI Approved :: MIT License",
         "Operating System :: POSIX :: Linux",
         "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",