feat: support Python version for --python arg when py launcher is n… (

#1343) * feat: support Python version for `--python` arg when py launcher is not available * fix test * update help message * fix test * update test * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * fix test * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * fix test * Apply suggestions from code review Co-authored-by: chrysle <[email protected]> * refine the tests * Simplify micro version check to warning * fix test * return python_path instead of python_command * fix test * Apply suggestions from code review Co-authored-by: chrysle <[email protected]> * revert changes in test_interpreter. * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * Update src/pipx/interpreter.py Co-authored-by: chrysle <[email protected]> * minor --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: chrysle <[email protected]>
pypa · Apr 27, 2024 · c4f35c8 · c4f35c8
1 parent c44d210
commit c4f35c8
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Showing 5 changed files with 115 additions and 10 deletions.
diff --git a/changelog.d/1342.feature.md b/changelog.d/1342.feature.md
@@ -0,0 +1 @@
+Support Python version for `--python` arg when py launcher is not available
diff --git a/src/pipx/interpreter.py b/src/pipx/interpreter.py
@@ -6,6 +6,8 @@
 from pathlib import Path
 from typing import Optional
 
+from packaging import version
+
 from pipx.constants import FETCH_MISSING_PYTHON, WINDOWS
 from pipx.standalone_python import download_python_build_standalone
 from pipx.util import PipxError
@@ -41,27 +43,63 @@ def __init__(self, source: str, version: str, wrap_message: bool = True):
                 message += "The provided version looks like a path, but no executable was found there."
             if potentially_pylauncher:
                 message += (
-                    "The provided version looks like a version for Python Launcher, " "but `py` was not found on PATH."
+                    "The provided version looks like a version, "
+                    "but both the python command and the Python Launcher were not found on PATH."
                 )
         if source == "the python-build-standalone project":
             message += "listed in https://github.com/indygreg/python-build-standalone/releases/latest."
         super().__init__(message, wrap_message)
 
 
+def find_unix_command_python(python_version: str) -> Optional[str]:
+    try:
+        parsed_python_version = version.parse(python_version)
+    except version.InvalidVersion:
+        logger.info(f"Invalid Python version: {python_version}")
+        return None
+
+    if (
+        parsed_python_version.epoch != 0
+        or parsed_python_version.is_devrelease
+        or parsed_python_version.is_postrelease
+        or parsed_python_version.is_prerelease
+    ):
+        logger.info(f"Unsupported Python version: {python_version}")
+        return None
+
+    # Python command could be `python3` or `python3.x` without micro version component
+    python_command = f"python{'.'.join(python_version.split('.')[:2])}"
+
+    python_path = shutil.which(python_command)
+    if not python_path:
+        logger.info(f"Command `{python_command}` was not found on the system")
+        return None
+
+    if parsed_python_version.micro != 0:
+        logger.warning(
+            f"The command '{python_command}' located at '{python_path}' will be used. "
+            f"It may not match the specified version {python_version} at the micro/patch level."
+        )
+
+    return python_path
+
+
 def find_python_interpreter(python_version: str, fetch_missing_python: bool = False) -> str:
-    if Path(python_version).is_file():
+    if Path(python_version).is_file() or shutil.which(python_version):
         return python_version
 
+    if not WINDOWS:
+        python_unix_command = find_unix_command_python(python_version)
+        if python_unix_command:
+            return python_unix_command
+
     try:
         py_executable = find_py_launcher_python(python_version)
         if py_executable:
             return py_executable
     except (subprocess.CalledProcessError, FileNotFoundError) as e:
         raise InterpreterResolutionError(source="py launcher", version=python_version) from e
 
-    if shutil.which(python_version):
-        return python_version
-
     if fetch_missing_python or FETCH_MISSING_PYTHON:
         try:
             standalone_executable = download_python_build_standalone(python_version)

diff --git a/src/pipx/main.py b/src/pipx/main.py
@@ -428,8 +428,8 @@ def add_python_options(parser: argparse.ArgumentParser) -> None:
         "--python",
         help=(
             "Python to install with. Possible values can be the executable name (python3.11), "
-            "the version to pass to py launcher (3.11), or the full path to the executable."
-            f"Requires Python {MINIMUM_PYTHON_VERSION} or above."
+            "the version of an available system Python or to pass to py launcher (3.11), "
+            f"or the full path to the executable. Requires Python {MINIMUM_PYTHON_VERSION} or above."
         ),
     )
     parser.add_argument(

diff --git a/tests/test_install.py b/tests/test_install.py
@@ -377,3 +377,61 @@ def test_install_fetch_missing_python_invalid(capsys, python_version):
     assert run_pipx_cli(["install", "--python", python_version, "--fetch-missing-python", "pycowsay"])
     captured = capsys.readouterr()
     assert f"No executable for the provided Python version '{python_version}' found" in captured.out
+
+
+def test_install_run_in_separate_directory(caplog, capsys, pipx_temp_env, monkeypatch, tmp_path):
+    monkeypatch.chdir(tmp_path)
+    f = Path("argparse.py")
+    f.touch()
+
+    install_packages(capsys, pipx_temp_env, caplog, ["pycowsay"], ["pycowsay"])
+
+
+@skip_if_windows
+@pytest.mark.parametrize(
+    "python_version",
+    [
+        str(sys.version_info.major),
+        f"{sys.version_info.major}.{sys.version_info.minor}",
+        f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}",
+    ],
+)
+def test_install_python_command_version(pipx_temp_env, monkeypatch, capsys, python_version):
+    monkeypatch.setenv("PATH", os.getenv("PATH_ORIG"))
+    assert not run_pipx_cli(["install", "--python", python_version, "--verbose", "pycowsay"])
+    captured = capsys.readouterr()
+    assert python_version in captured.out
+
+
+@skip_if_windows
+def test_install_python_command_version_invalid(pipx_temp_env, capsys):
+    python_version = "3.x"
+    assert run_pipx_cli(["install", "--python", python_version, "--verbose", "pycowsay"])
+    captured = capsys.readouterr()
+    assert f"Invalid Python version: {python_version}" in captured.err
+
+
+@skip_if_windows
+def test_install_python_command_version_unsupported(pipx_temp_env, capsys):
+    python_version = f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}.dev"
+    assert run_pipx_cli(["install", "--python", python_version, "--verbose", "pycowsay"])
+    captured = capsys.readouterr()
+    assert f"Unsupported Python version: {python_version}" in captured.err
+
+
+@skip_if_windows
+def test_install_python_command_version_missing(pipx_temp_env, monkeypatch, capsys):
+    monkeypatch.setenv("PATH", os.getenv("PATH_ORIG"))
+    python_version = f"{sys.version_info.major + 99}.{sys.version_info.minor}"
+    assert run_pipx_cli(["install", "--python", python_version, "--verbose", "pycowsay"])
+    captured = capsys.readouterr()
+    assert f"Command `python{python_version}` was not found" in captured.err
+
+
+@skip_if_windows
+def test_install_python_command_version_micro_mismatch(pipx_temp_env, monkeypatch, capsys):
+    monkeypatch.setenv("PATH", os.getenv("PATH_ORIG"))
+    python_version = f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro + 1}"
+    assert not run_pipx_cli(["install", "--python", python_version, "--verbose", "pycowsay"])
+    captured = capsys.readouterr()
+    assert f"It may not match the specified version {python_version} at the micro/patch level" in captured.err
diff --git a/tests/test_interpreter.py b/tests/test_interpreter.py
@@ -17,12 +17,16 @@
 )
 from pipx.util import PipxError
 
+original_which = shutil.which
+
 
 @pytest.mark.skipif(not sys.platform.startswith("win"), reason="Looks for Python.exe")
 @pytest.mark.parametrize("venv", [True, False])
 def test_windows_python_with_version(monkeypatch, venv):
     def which(name):
-        return "py"
+        if name == "py":
+            return "py"
+        return original_which(name)
 
     major = sys.version_info.major
     minor = sys.version_info.minor
@@ -38,7 +42,9 @@ def which(name):
 @pytest.mark.parametrize("venv", [True, False])
 def test_windows_python_with_python_and_version(monkeypatch, venv):
     def which(name):
-        return "py"
+        if name == "py":
+            return "py"
+        return original_which(name)
 
     major = sys.version_info.major
     minor = sys.version_info.minor
@@ -54,7 +60,9 @@ def which(name):
 @pytest.mark.parametrize("venv", [True, False])
 def test_windows_python_with_python_and_unavailable_version(monkeypatch, venv):
     def which(name):
-        return "py"
+        if name == "py":
+            return "py"
+        return original_which(name)
 
     major = sys.version_info.major + 99
     minor = sys.version_info.minor
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Support Python version for `--python` arg when py launcher is not available