Change min-py3-version behavior

README.md

@@ -123,12 +123,13 @@ This will show up on the pypi project page
 
 ### set `python_requires`
 
-A few sources are searched for guessing `python_requires`:
+If `--min-py-version` is passed, it will be used to set `python_requires`.
+
+Otherwise, the following sources are searched:
 
 - the existing `python_requires` setting itself
 - `envlist` in `tox.ini` if present
 - python version `classifiers` that are already set
-- the `--min-py3-version` argument (currently defaulting to `3.7`)
 
 If the minimum version is detected as python2, the `--min-py3-version`
 argument will be used to exclude python3.x versions (see below).
@@ -151,8 +152,6 @@ classifiers are generated based on:
  name = pkg
  version = 1.0
 +classifiers =
-+    Programming Language :: Python :: 2
-+    Programming Language :: Python :: 2.7
 +    Programming Language :: Python :: 3
 +    Programming Language :: Python :: 3.7
 +    Programming Language :: Python :: 3.8
@@ -167,7 +166,6 @@ without `--include-version-classifiers` only the major version will be included:
  name = pkg
  version = 1.0
 +classifiers =
-+    Programming Language :: Python :: 2
 +    Programming Language :: Python :: 3
 ```
 

setup_cfg_fmt.py

@@ -116,8 +116,8 @@ def sort_key(filename: str) -> tuple[bool, str]:
         return None
 
 
-def _py3_excluded(min_py3_version: tuple[int, int]) -> set[tuple[int, int]]:
-    _, end = min_py3_version
+def _py3_excluded(min_py_version: tuple[int, int]) -> set[tuple[int, int]]:
+    _, end = min_py_version
     return {(3, i) for i in range(end)}
 
 
@@ -162,6 +162,33 @@ def _parse_python_requires(
     return minimum, excluded
 
 
+def _parse_envlist(setup_cfg: str) -> Version | None:
+    return min(
+        (
+            _to_ver('.'.join(env[2:]))
+            for env in _tox_envlist(setup_cfg)
+            if (
+                env.startswith('py') and
+                len(env) == 4 and
+                env[2:].isdigit()
+            )
+        ),
+        default=None,
+    )
+
+
+def _parse_classifiers(classifiers: str) -> Version | None:
+    def gen() -> Generator[Version, None, None]:
+        for classifier in classifiers.strip().splitlines():
+            if classifier.startswith('Programming Language :: Python ::'):
+                version_part = classifier.split()[-1]
+                if '.' not in version_part:
+                    continue
+                yield _to_ver(version_part)
+
+    return min(gen(), default=None)
+
+
 def _tox_envlist(setup_cfg: str) -> Generator[str, None, None]:
     tox_ini = _adjacent_filename(setup_cfg, 'tox.ini')
     if os.path.exists(tox_ini):
@@ -176,46 +203,43 @@ def _tox_envlist(setup_cfg: str) -> Generator[str, None, None]:
 
 
 def _python_requires(
-        setup_cfg: str, *, min_py3_version: tuple[int, int],
+        setup_cfg: str, *, min_py_version: tuple[int, int],
 ) -> str | None:
     cfg = NoTransformConfigParser()
     cfg.read(setup_cfg)
     current_value = cfg.get('options', 'python_requires', fallback='')
     classifiers = cfg.get('metadata', 'classifiers', fallback='')
 
     try:
-        minimum, excluded = _parse_python_requires(current_value)
+        min_from_py_requires, excluded = _parse_python_requires(current_value)
     except UnknownVersionError:  # assume they know what's up with weird things
         return current_value
 
-    for env in _tox_envlist(setup_cfg):
-        if (
-                env.startswith('py') and
-                len(env) == 4 and
-                env[2:].isdigit()
-        ):
-            version = _to_ver('.'.join(env[2:]))
-            if minimum is None or version < minimum[:2]:
-                minimum = version
-
-    for classifier in classifiers.strip().splitlines():
-        if classifier.startswith('Programming Language :: Python ::'):
-            version_part = classifier.split()[-1]
-            if '.' not in version_part:
-                continue
-            version = _to_ver(version_part)
-            if minimum is None or version < minimum[:2]:
-                minimum = version
-
-    if minimum is None:
-        return None
-    elif minimum[0] == 2:
-        excluded.update(_py3_excluded(min_py3_version))
-        return _format_python_requires(minimum, excluded)
-    elif min_py3_version > minimum:
-        return _format_python_requires(min_py3_version, excluded)
+    if isinstance(min_py_version, ImplicitlySetVersion):
+        min_from_envlist = _parse_envlist(setup_cfg)
+        min_from_classifiers = _parse_classifiers(classifiers)
+
+        mins = tuple(
+            v for v in (
+                min_from_py_requires,
+                min_from_envlist,
+                min_from_classifiers,
+            )
+            if v
+        )
+        if not mins:
+            return None
+
+        min_overall = min(mins, key=lambda v: v[:2])
     else:
-        return _format_python_requires(minimum, excluded)
+        min_overall = min_py_version
+
+    if min_overall[0] == 2:
+        excluded.update(_py3_excluded(min_py_version))
+
+    excluded.difference_update({e for e in excluded if e < min_overall})
+
+    return _format_python_requires(min_overall, excluded)
 
 
 def _requires(
@@ -368,7 +392,7 @@ def _natural_sort(items: Sequence[str]) -> list[str]:
 def format_file(
         filename: str, *,
         include_version_classifiers: bool,
-        min_py3_version: tuple[int, int],
+        min_py_version: tuple[int, int],
         max_py_version: tuple[int, int],
 ) -> bool:
     with open(filename) as f:
@@ -415,7 +439,7 @@ def format_file(
                 f'\n{LICENSE_TO_CLASSIFIER[license_id]}'
             )
 
-    requires = _python_requires(filename, min_py3_version=min_py3_version)
+    requires = _python_requires(filename, min_py_version=min_py_version)
     if requires is not None:
         if not cfg.has_section('options'):
             cfg.add_section('options')
@@ -515,20 +539,31 @@ def _ver_type(s: str) -> Version:
         return version
 
 
+class ImplicitlySetVersion(Version):
+    def __new__(self, x: int, y: int) -> ImplicitlySetVersion:
+        return tuple.__new__(ImplicitlySetVersion, (x, y))
+
+
 def main(argv: Sequence[str] | None = None) -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument('filenames', nargs='*')
     parser.add_argument('--include-version-classifiers', action='store_true')
-    parser.add_argument('--min-py3-version', type=_ver_type, default=(3, 7))
-    parser.add_argument('--max-py-version', type=_ver_type, default=(3, 11))
+    parser.add_argument(
+        '--min-py-version',
+        type=_ver_type, default=ImplicitlySetVersion(3, 7),
+    )
+    parser.add_argument(
+        '--max-py-version',
+        type=_ver_type, default=ImplicitlySetVersion(3, 11),
+    )
     args = parser.parse_args(argv)
 
     retv = 0
     for filename in args.filenames:
         if format_file(
                 filename,
                 include_version_classifiers=args.include_version_classifiers,
-                min_py3_version=args.min_py3_version,
+                min_py_version=args.min_py_version,
                 max_py_version=args.max_py_version,
         ):
             print(f'Rewriting {filename}')