Foundation for detecting python version requirements from pyproject.toml (#643)

Author: amol-

pyproject.toml

@@ -13,6 +13,7 @@ dependencies = [
     "semver>=2.0.0,<4.0.0",
     "pyjwt>=2.4.0",
     "click>=8.0.0",
+    "toml>=0.10; python_version < '3.11'"
 ]
 
 dynamic = ["version"]
@@ -82,6 +83,9 @@ rsconnect = ["py.typed"]
 
 [tool.pytest.ini_options]
 markers = ["vetiver: tests for vetiver"]
+addopts = """
+    --ignore=tests/testdata
+"""
 
 [tool.pyright]
 typeCheckingMode = "strict"

rsconnect/pyproject.py

@@ -0,0 +1,45 @@
+"""
+Support for detecting various information from python projects metadata.
+
+Metadata can only be loaded from static files (e.g. pyproject.toml, setup.cfg, etc.)
+but not from setup.py due to its dynamic nature.
+"""
+
+import pathlib
+import typing
+
+try:
+    import tomllib
+except ImportError:
+    # Python 3.11+ has tomllib in the standard library
+    import toml as tomllib  # type: ignore[no-redef]
+
+
+def lookup_metadata_file(directory: typing.Union[str, pathlib.Path]) -> typing.List[typing.Tuple[str, pathlib.Path]]:
+    """Given the directory of a project return the path of a usable metadata file.
+
+    The returned value is either a list of tuples [(filename, path)] or
+    an empty list [] if no metadata file was found.
+    """
+    directory = pathlib.Path(directory)
+
+    def _generate():
+        for filename in ("pyproject.toml", "setup.cfg", ".python-version"):
+            path = directory / filename
+            if path.is_file():
+                yield (filename, path)
+
+    return list(_generate())
+
+
+def parse_pyproject_python_requires(pyproject_file: pathlib.Path) -> typing.Optional[str]:
+    """Parse the project.requires-python field from a pyproject.toml file.
+
+    Assumes that the pyproject.toml file exists, is accessible and well formatted.
+
+    Returns None if the field is not found.
+    """
+    content = pyproject_file.read_text()
+    pyproject = tomllib.loads(content)
+
+    return pyproject.get("project", {}).get("requires-python", None)

tests/test_pyproject.py

@@ -0,0 +1,67 @@
+import os
+import pathlib
+
+from rsconnect.pyproject import lookup_metadata_file, parse_pyproject_python_requires
+
+import pytest
+
+HERE = os.path.dirname(__file__)
+PROJECTS_DIRECTORY = os.path.abspath(os.path.join(HERE, "testdata", "python-project"))
+
+# 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.
+# - allofthem: contains all metadata files all with different version constraints.
+
+
+@pytest.mark.parametrize(
+    "project_dir, expected",
+    [
+        (os.path.join(PROJECTS_DIRECTORY, "using_pyproject"), ("pyproject.toml",)),
+        (os.path.join(PROJECTS_DIRECTORY, "using_setupcfg"), ("setup.cfg",)),
+        (
+            os.path.join(PROJECTS_DIRECTORY, "using_pyversion"),
+            (
+                "pyproject.toml",
+                ".python-version",
+            ),
+        ),
+        (os.path.join(PROJECTS_DIRECTORY, "allofthem"), ("pyproject.toml", "setup.cfg", ".python-version")),
+    ],
+    ids=["pyproject.toml", "setup.cfg", ".python-version", "allofthem"],
+)
+def test_python_project_metadata_detect(project_dir, expected):
+    """Test that the metadata files are detected when they exist."""
+    expectation = [(f, pathlib.Path(project_dir) / f) for f in expected]
+    assert lookup_metadata_file(project_dir) == expectation
+
+
+@pytest.mark.parametrize(
+    "project_dir",
+    [
+        os.path.join(PROJECTS_DIRECTORY, "empty"),
+        os.path.join(PROJECTS_DIRECTORY, "missing"),
+    ],
+    ids=["empty", "missing"],
+)
+def test_python_project_metadata_missing(project_dir):
+    """Test that lookup_metadata_file is able to deal with missing or empty directories."""
+    assert lookup_metadata_file(project_dir) == []
+
+
+@pytest.mark.parametrize(
+    "project_dir, expected",
+    [
+        (os.path.join(PROJECTS_DIRECTORY, "using_pyproject"), ">=3.8"),
+        (os.path.join(PROJECTS_DIRECTORY, "using_pyversion"), None),
+    ],
+    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.
+
+    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

tests/testdata/python-project/allofthem/.python-version

@@ -0,0 +1 @@
+>=3.8, <3.12

tests/testdata/python-project/allofthem/hello.py

@@ -0,0 +1,6 @@
+def main():
+    print("Hello from python-project!")
+
+
+if __name__ == "__main__":
+    main()

tests/testdata/python-project/allofthem/pyproject.toml

@@ -0,0 +1,6 @@
+[project]
+name = "python-project"
+version = "0.1.0"
+description = "Add your description here"
+requires-python = ">=3.8"
+dependencies = []

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

@@ -0,0 +1,7 @@
+[metadata]
+name = python-project
+version = 0.1.0
+description = Add your description here
+
+[options]
+python_requires = >=3.8

tests/testdata/python-project/empty/hello.py

@@ -0,0 +1,6 @@
+def main():
+    print("Hello from python-project!")
+
+
+if __name__ == "__main__":
+    main()

tests/testdata/python-project/using_pyproject/hello.py

@@ -0,0 +1,6 @@
+def main():
+    print("Hello from python-project!")
+
+
+if __name__ == "__main__":
+    main()

tests/testdata/python-project/using_pyproject/pyproject.toml

@@ -0,0 +1,6 @@
+[project]
+name = "python-project"
+version = "0.1.0"
+description = "Add your description here"
+requires-python = ">=3.8"
+dependencies = []