Parser for interpreter version requirements from setup.cfg .python-version (#645)

* Support for parsing setup.cfg and python-version, detection of parser

Author: amol-

rsconnect/pyproject.py

@@ -7,6 +7,7 @@
 
 import pathlib
 import typing
+import configparser
 
 try:
     import tomllib
@@ -20,18 +21,38 @@ def lookup_metadata_file(directory: typing.Union[str, pathlib.Path]) -> typing.L
 
     The returned value is either a list of tuples [(filename, path)] or
     an empty list [] if no metadata file was found.
+
+    The metadata files are returned in the priority they should be processed
+    to determine the python version requirements.
     """
     directory = pathlib.Path(directory)
 
     def _generate():
-        for filename in ("pyproject.toml", "setup.cfg", ".python-version"):
+        for filename in (".python-version", "pyproject.toml", "setup.cfg"):
             path = directory / filename
             if path.is_file():
                 yield (filename, path)
 
     return list(_generate())
 
 
+def get_python_version_requirement_parser(
+    metadata_file: pathlib.Path,
+) -> typing.Optional[typing.Callable[[pathlib.Path], typing.Optional[str]]]:
+    """Given the metadata file, return the appropriate parser function.
+
+    The returned function takes a pathlib.Path and returns the parsed value.
+    """
+    if metadata_file.name == "pyproject.toml":
+        return parse_pyproject_python_requires
+    elif metadata_file.name == "setup.cfg":
+        return parse_setupcfg_python_requires
+    elif metadata_file.name == ".python-version":
+        return parse_pyversion_python_requires
+    else:
+        return None
+
+
 def parse_pyproject_python_requires(pyproject_file: pathlib.Path) -> typing.Optional[str]:
     """Parse the project.requires-python field from a pyproject.toml file.
 
@@ -43,3 +64,27 @@ def parse_pyproject_python_requires(pyproject_file: pathlib.Path) -> typing.Opti
     pyproject = tomllib.loads(content)
 
     return pyproject.get("project", {}).get("requires-python", None)
+
+
+def parse_setupcfg_python_requires(setupcfg_file: pathlib.Path) -> typing.Optional[str]:
+    """Parse the options.python_requires field from a setup.cfg file.
+
+    Assumes that the setup.cfg file exists, is accessible and well formatted.
+
+    Returns None if the field is not found.
+    """
+    config = configparser.ConfigParser()
+    config.read(setupcfg_file)
+
+    return config.get("options", "python_requires", fallback=None)
+
+
+def parse_pyversion_python_requires(pyversion_file: pathlib.Path) -> typing.Optional[str]:
+    """Parse the python version from a .python-version file.
+
+    Assumes that the .python-version file exists, is accessible and well formatted.
+
+    Returns None if the field is not found.
+    """
+    content = pyversion_file.read_text()
+    return content.strip()

tests/test_pyproject.py

@@ -1,7 +1,13 @@
 import os
 import pathlib
 
-from rsconnect.pyproject import lookup_metadata_file, parse_pyproject_python_requires
+from rsconnect.pyproject import (
+    lookup_metadata_file,
+    parse_pyproject_python_requires,
+    parse_setupcfg_python_requires,
+    parse_pyversion_python_requires,
+    get_python_version_requirement_parser,
+)
 
 import pytest
 
@@ -11,7 +17,7 @@
 # Most of this tests, verify against three fixture projects that are located in PROJECTS_DIRECTORY
 # - using_pyproject: contains a pyproject.toml file with a project.requires-python field
 # - using_setupcfg: contains a setup.cfg file with a options.python_requires field
-# - using_pyversion: contains a .python-version file and a pyproject.toml file without any version constraint.
+# - using_pyversion: contains a .python-version file and pyproject.toml, setup.cfg without any version constraint.
 # - allofthem: contains all metadata files all with different version constraints.
 
 
@@ -23,11 +29,12 @@
         (
             os.path.join(PROJECTS_DIRECTORY, "using_pyversion"),
             (
-                "pyproject.toml",
                 ".python-version",
+                "pyproject.toml",
+                "setup.cfg",
             ),
         ),
-        (os.path.join(PROJECTS_DIRECTORY, "allofthem"), ("pyproject.toml", "setup.cfg", ".python-version")),
+        (os.path.join(PROJECTS_DIRECTORY, "allofthem"), (".python-version", "pyproject.toml", "setup.cfg")),
     ],
     ids=["pyproject.toml", "setup.cfg", ".python-version", "allofthem"],
 )
@@ -37,6 +44,23 @@ def test_python_project_metadata_detect(project_dir, expected):
     assert lookup_metadata_file(project_dir) == expectation
 
 
+@pytest.mark.parametrize(
+    "filename, expected_parser",
+    [
+        ("pyproject.toml", parse_pyproject_python_requires),
+        ("setup.cfg", parse_setupcfg_python_requires),
+        (".python-version", parse_pyversion_python_requires),
+        ("invalid.txt", None),
+    ],
+    ids=["pyproject.toml", "setup.cfg", ".python-version", "invalid"],
+)
+def test_get_python_version_requirement_parser(filename, expected_parser):
+    """Test that given a metadata file name, the correct parser is returned."""
+    metadata_file = pathlib.Path(PROJECTS_DIRECTORY) / filename
+    parser = get_python_version_requirement_parser(metadata_file)
+    assert parser == expected_parser
+
+
 @pytest.mark.parametrize(
     "project_dir",
     [
@@ -59,9 +83,43 @@ def test_python_project_metadata_missing(project_dir):
     ids=["option-exists", "option-missing"],
 )
 def test_pyprojecttoml_python_requires(project_dir, expected):
-    """Test that the python_requires field is correctly parsed from pyproject.toml.
+    """Test that the requires-python field is correctly parsed from pyproject.toml.
 
     Both when the option exists or when it missing in the pyproject.toml file.
     """
     pyproject_file = pathlib.Path(project_dir) / "pyproject.toml"
     assert parse_pyproject_python_requires(pyproject_file) == expected
+
+
+@pytest.mark.parametrize(
+    "project_dir, expected",
+    [
+        (os.path.join(PROJECTS_DIRECTORY, "using_setupcfg"), ">=3.8"),
+        (os.path.join(PROJECTS_DIRECTORY, "using_pyversion"), None),
+    ],
+    ids=["option-exists", "option-missing"],
+)
+def test_setupcfg_python_requires(tmp_path, project_dir, expected):
+    """Test that the python_requires field is correctly parsed from setup.cfg.
+
+    Both when the option exists or when it missing in the file.
+    """
+    setupcfg_file = pathlib.Path(project_dir) / "setup.cfg"
+    assert parse_setupcfg_python_requires(setupcfg_file) == expected
+
+
+@pytest.mark.parametrize(
+    "project_dir, expected",
+    [
+        (os.path.join(PROJECTS_DIRECTORY, "using_pyversion"), ">=3.8, <3.12"),
+    ],
+    ids=["option-exists"],
+)
+def test_pyversion_python_requires(tmp_path, project_dir, expected):
+    """Test that the python version is correctly parsed from .python-version.
+
+    We do not test the case where the option is missing, as an empty .python-version file
+    is not a valid case for a python project.
+    """
+    versionfile = pathlib.Path(project_dir) / ".python-version"
+    assert parse_pyversion_python_requires(versionfile) == expected

tests/testdata/python-project/using_pyversion/setup.cfg

@@ -0,0 +1,4 @@
+[metadata]
+name = python-project
+version = 0.1.0
+description = Add your description here