python-virtualenv/prs-2709-and-2712.patch

From 71de653a714958d6649501b874009bafec74d3f4 Mon Sep 17 00:00:00 2001
From: Philipp A <flying-sheep@web.de>
Date: Tue, 23 Apr 2024 18:46:41 +0200
Subject: [PATCH 1/2] Allow builtin interpreter discovery to find specific
 Python versions given a general spec (#2709)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Bernát Gábor <gaborjbernat@gmail.com>

Backported to 20.21.1 (without typing improvements).
---
 docs/changelog/2709.bugfix.rst         |  1 +
 src/virtualenv/discovery/builtin.py    | 78 +++++++++++++-------------
 src/virtualenv/discovery/py_spec.py    | 42 ++++++--------
 tests/unit/discovery/test_discovery.py | 15 ++++-
 4 files changed, 67 insertions(+), 69 deletions(-)
 create mode 100644 docs/changelog/2709.bugfix.rst

diff --git a/docs/changelog/2709.bugfix.rst b/docs/changelog/2709.bugfix.rst
new file mode 100644
index 0000000..904da84
--- /dev/null
+++ b/docs/changelog/2709.bugfix.rst
@@ -0,0 +1 @@
+allow builtin discovery to discover specific interpreters (e.g. ``python3.12``) given an unspecific spec (e.g. ``python3``) - by :user:`flying-sheep`.
diff --git a/src/virtualenv/discovery/builtin.py b/src/virtualenv/discovery/builtin.py
index 40320d3..f79b5a5 100644
--- a/src/virtualenv/discovery/builtin.py
+++ b/src/virtualenv/discovery/builtin.py
@@ -1,6 +1,7 @@
 import logging
 import os
 import sys
+from pathlib import Path
 
 from virtualenv.info import IS_WIN
 
@@ -67,7 +68,7 @@ def get_interpreter(key, try_first_with, app_data=None, env=None):
         proposed_paths.add(key)
 
 
-def propose_interpreters(spec, try_first_with, app_data, env=None):
+def propose_interpreters(spec, try_first_with, app_data=None, env=None):  # noqa: C901, PLR0912
     # 0. try with first
     env = os.environ if env is None else env
     for py_exe in try_first_with:
@@ -101,20 +102,17 @@ def propose_interpreters(spec, try_first_with, app_data, env=None):
             for interpreter in propose_interpreters(spec, app_data, env):
                 yield interpreter, True
     # finally just find on path, the path order matters (as the candidates are less easy to control by end user)
-    paths = get_paths(env)
     tested_exes = set()
-    for pos, path in enumerate(paths):
-        path_str = str(path)
-        logging.debug(LazyPathDump(pos, path_str, env))
-        for candidate, match in possible_specs(spec):
-            found = check_path(candidate, path_str)
-            if found is not None:
-                exe = os.path.abspath(found)
-                if exe not in tested_exes:
-                    tested_exes.add(exe)
-                    interpreter = PathPythonInfo.from_exe(exe, app_data, raise_on_error=False, env=env)
-                    if interpreter is not None:
-                        yield interpreter, match
+    find_candidates = path_exe_finder(spec)
+    for pos, path in enumerate(get_paths(env)):
+        logging.debug(LazyPathDump(pos, path, env))
+        for exe, impl_must_match in find_candidates(path):
+            if exe in tested_exes:
+                continue
+            tested_exes.add(exe)
+            interpreter = PathPythonInfo.from_exe(str(exe), app_data, raise_on_error=False, env=env)
+            if interpreter is not None:
+                yield interpreter, impl_must_match
 
 
 def get_paths(env):
@@ -125,14 +123,14 @@ def get_paths(env):
         except (AttributeError, ValueError):
             path = os.defpath
     if not path:
-        paths = []
-    else:
-        paths = [p for p in path.split(os.pathsep) if os.path.exists(p)]
-    return paths
+        return None
+    for p in map(Path, path.split(os.pathsep)):
+        if p.exists():
+            yield p
 
 
 class LazyPathDump:
-    def __init__(self, pos, path, env):
+    def __init__(self, pos, path, env) -> None:
         self.pos = pos
         self.path = path
         self.env = env
@@ -141,35 +139,35 @@ class LazyPathDump:
         content = f"discover PATH[{self.pos}]={self.path}"
         if self.env.get("_VIRTUALENV_DEBUG"):  # this is the over the board debug
             content += " with =>"
-            for file_name in os.listdir(self.path):
+            for file_path in self.path.iterdir():
                 try:
-                    file_path = os.path.join(self.path, file_name)
-                    if os.path.isdir(file_path) or not os.access(file_path, os.X_OK):
+                    if file_path.is_dir() or not (file_path.stat().st_mode & os.X_OK):
                         continue
                 except OSError:
                     pass
                 content += " "
-                content += file_name
+                content += file_path.name
         return content
 
 
-def check_path(candidate, path):
-    _, ext = os.path.splitext(candidate)
-    if sys.platform == "win32" and ext != ".exe":
-        candidate = candidate + ".exe"
-    if os.path.isfile(candidate):
-        return candidate
-    candidate = os.path.join(path, candidate)
-    if os.path.isfile(candidate):
-        return candidate
-    return None
-
-
-def possible_specs(spec):
-    # 4. then maybe it's something exact on PATH - if it was direct lookup implementation no longer counts
-    yield spec.str_spec, False
-    # 5. or from the spec we can deduce a name on path  that matches
-    yield from spec.generate_names()
+def path_exe_finder(spec):
+    """Given a spec, return a function that can be called on a path to find all matching files in it."""
+    pat = spec.generate_re(windows=sys.platform == "win32")
+    direct = spec.str_spec
+    if sys.platform == "win32":
+        direct = f"{direct}.exe"
+
+    def path_exes(path):
+        # 4. then maybe it's something exact on PATH - if it was direct lookup implementation no longer counts
+        yield (path / direct), False
+        # 5. or from the spec we can deduce if a name on path matches
+        for exe in path.iterdir():
+            match = pat.fullmatch(exe.name)
+            if match:
+                # the implementation must match when we find “python[ver]”
+                yield exe.absolute(), match["impl"] == "python"
+
+    return path_exes
 
 
 class PathPythonInfo(PythonInfo):
diff --git a/src/virtualenv/discovery/py_spec.py b/src/virtualenv/discovery/py_spec.py
index 103c7ae..cbfdfb8 100644
--- a/src/virtualenv/discovery/py_spec.py
+++ b/src/virtualenv/discovery/py_spec.py
@@ -1,10 +1,9 @@
 """A Python specification is an abstract requirement definition of an interpreter"""
 
+from __future__ import annotations
+
 import os
 import re
-from collections import OrderedDict
-
-from virtualenv.info import fs_is_case_sensitive
 
 PATTERN = re.compile(r"^(?P<impl>[a-zA-Z]+)?(?P<version>[0-9.]+)?(?:-(?P<arch>32|64))?$")
 
@@ -12,7 +11,7 @@ PATTERN = re.compile(r"^(?P<impl>[a-zA-Z]+)?(?P<version>[0-9.]+)?(?:-(?P<arch>32
 class PythonSpec:
     """Contains specification about a Python Interpreter"""
 
-    def __init__(self, str_spec, implementation, major, minor, micro, architecture, path):
+    def __init__(self, str_spec, implementation, major, minor, micro, architecture, path) -> None: # noqa: PLR0913
         self.str_spec = str_spec
         self.implementation = implementation
         self.major = major
@@ -22,7 +21,7 @@ class PythonSpec:
         self.path = path
 
     @classmethod
-    def from_string_spec(cls, string_spec):
+    def from_string_spec(cls, string_spec):  # noqa: C901, PLR0912
         impl, major, minor, micro, arch, path = None, None, None, None, None, None
         if os.path.isabs(string_spec):
             path = string_spec
@@ -64,27 +63,18 @@ class PythonSpec:
 
         return cls(string_spec, impl, major, minor, micro, arch, path)
 
-    def generate_names(self):
-        impls = OrderedDict()
-        if self.implementation:
-            # first consider implementation as it is
-            impls[self.implementation] = False
-            if fs_is_case_sensitive():
-                # for case sensitive file systems consider lower and upper case versions too
-                # trivia: MacBooks and all pre 2018 Windows-es were case insensitive by default
-                impls[self.implementation.lower()] = False
-                impls[self.implementation.upper()] = False
-        impls["python"] = True  # finally consider python as alias, implementation must match now
-        version = self.major, self.minor, self.micro
-        try:
-            version = version[: version.index(None)]
-        except ValueError:
-            pass
-        for impl, match in impls.items():
-            for at in range(len(version), -1, -1):
-                cur_ver = version[0:at]
-                spec = f"{impl}{'.'.join(str(i) for i in cur_ver)}"
-                yield spec, match
+    def generate_re(self, *, windows):
+        """Generate a regular expression for matching against a filename."""
+        version = r"{}(\.{}(\.{})?)?".format(
+            *(r"\d+" if v is None else v for v in (self.major, self.minor, self.micro))
+        )
+        impl = "python" if self.implementation is None else f"python|{re.escape(self.implementation)}"
+        suffix = r"\.exe" if windows else ""
+        # Try matching `direct` first, so the `direct` group is filled when possible.
+        return re.compile(
+            rf"(?P<impl>{impl})(?P<v>{version}){suffix}$",
+            flags=re.IGNORECASE,
+        )
 
     @property
     def is_abs(self):
diff --git a/tests/unit/discovery/test_discovery.py b/tests/unit/discovery/test_discovery.py
index c4a2cc7..51bae24 100644
--- a/tests/unit/discovery/test_discovery.py
+++ b/tests/unit/discovery/test_discovery.py
@@ -14,16 +14,25 @@ from virtualenv.info import fs_supports_symlink
 
 @pytest.mark.skipif(not fs_supports_symlink(), reason="symlink not supported")
 @pytest.mark.parametrize("case", ["mixed", "lower", "upper"])
-def test_discovery_via_path(monkeypatch, case, tmp_path, caplog, session_app_data):
+@pytest.mark.parametrize("specificity", ["more", "less"])
+def test_discovery_via_path(monkeypatch, case, specificity, tmp_path, caplog, session_app_data):  # noqa: PLR0913
     caplog.set_level(logging.DEBUG)
     current = PythonInfo.current_system(session_app_data)
-    core = f"somethingVeryCryptic{'.'.join(str(i) for i in current.version_info[0:3])}"
     name = "somethingVeryCryptic"
     if case == "lower":
         name = name.lower()
     elif case == "upper":
         name = name.upper()
-    exe_name = f"{name}{current.version_info.major}{'.exe' if sys.platform == 'win32' else ''}"
+    if specificity == "more":
+        # e.g. spec: python3, exe: /bin/python3.12
+        core_ver = current.version_info.major
+        exe_ver = ".".join(str(i) for i in current.version_info[0:2])
+    elif specificity == "less":
+        # e.g. spec: python3.12.1, exe: /bin/python3
+        core_ver = ".".join(str(i) for i in current.version_info[0:3])
+        exe_ver = current.version_info.major
+    core = f"somethingVeryCryptic{core_ver}"
+    exe_name = f"{name}{exe_ver}{'.exe' if sys.platform == 'win32' else ''}"
     target = tmp_path / current.install_path("scripts")
     target.mkdir(parents=True)
     executable = target / exe_name
-- 
2.45.2


From 4bb73d175614aa6041b1e9e57d7302b9c253b5ef Mon Sep 17 00:00:00 2001
From: Ofek Lev <ofekmeister@gmail.com>
Date: Sat, 27 Apr 2024 14:43:00 -0400
Subject: [PATCH 2/2] Fix PATH-based Python discovery on Windows (#2712)

---
 docs/changelog/2712.bugfix.rst         |  1 +
 src/virtualenv/discovery/builtin.py    | 44 ++++++++++++++++++++------
 src/virtualenv/discovery/py_spec.py    | 10 +++++-
 src/virtualenv/info.py                 |  5 +++
 tests/unit/discovery/test_discovery.py |  8 +++--
 5 files changed, 55 insertions(+), 13 deletions(-)
 create mode 100644 docs/changelog/2712.bugfix.rst

diff --git a/docs/changelog/2712.bugfix.rst b/docs/changelog/2712.bugfix.rst
new file mode 100644
index 0000000..fee5436
--- /dev/null
+++ b/docs/changelog/2712.bugfix.rst
@@ -0,0 +1 @@
+fix PATH-based Python discovery on Windows - by :user:`ofek`.
diff --git a/src/virtualenv/discovery/builtin.py b/src/virtualenv/discovery/builtin.py
index f79b5a5..456c68b 100644
--- a/src/virtualenv/discovery/builtin.py
+++ b/src/virtualenv/discovery/builtin.py
@@ -3,7 +3,7 @@ import os
 import sys
 from pathlib import Path
 
-from virtualenv.info import IS_WIN
+from virtualenv.info import IS_WIN, fs_path_id
 
 from .discover import Discover
 from .py_info import PythonInfo
@@ -68,9 +68,10 @@ def get_interpreter(key, try_first_with, app_data=None, env=None):
         proposed_paths.add(key)
 
 
-def propose_interpreters(spec, try_first_with, app_data=None, env=None):  # noqa: C901, PLR0912
+def propose_interpreters(spec, try_first_with, app_data=None, env=None):  # noqa: C901, PLR0912, PLR0915
     # 0. try with first
     env = os.environ if env is None else env
+    tested_exes: set[str] = set()
     for py_exe in try_first_with:
         path = os.path.abspath(py_exe)
         try:
@@ -78,7 +79,12 @@ def propose_interpreters(spec, try_first_with, app_data=None, env=None):  # noqa
         except OSError:
             pass
         else:
-            yield PythonInfo.from_exe(os.path.abspath(path), app_data, env=env), True
+            exe_raw = os.path.abspath(path)
+            exe_id = fs_path_id(exe_raw)
+            if exe_id in tested_exes:
+                continue
+            tested_exes.add(exe_id)
+            yield PythonInfo.from_exe(exe_raw, app_data, env=env), True
 
     # 1. if it's a path and exists
     if spec.path is not None:
@@ -88,29 +94,44 @@ def propose_interpreters(spec, try_first_with, app_data=None, env=None):  # noqa
             if spec.is_abs:
                 raise
         else:
-            yield PythonInfo.from_exe(os.path.abspath(spec.path), app_data, env=env), True
+            exe_raw = os.path.abspath(spec.path)
+            exe_id = fs_path_id(exe_raw)
+            if exe_id not in tested_exes:
+                tested_exes.add(exe_id)
+                yield PythonInfo.from_exe(exe_raw, app_data, env=env), True
         if spec.is_abs:
             return
     else:
         # 2. otherwise try with the current
-        yield PythonInfo.current_system(app_data), True
+        current_python = PythonInfo.current_system(app_data)
+        exe_raw = str(current_python.executable)
+        exe_id = fs_path_id(exe_raw)
+        if exe_id not in tested_exes:
+            tested_exes.add(exe_id)
+            yield current_python, True
 
         # 3. otherwise fallback to platform default logic
         if IS_WIN:
             from .windows import propose_interpreters
 
             for interpreter in propose_interpreters(spec, app_data, env):
+                exe_raw = str(interpreter.executable)
+                exe_id = fs_path_id(exe_raw)
+                if exe_id in tested_exes:
+                    continue
+                tested_exes.add(exe_id)
                 yield interpreter, True
     # finally just find on path, the path order matters (as the candidates are less easy to control by end user)
-    tested_exes = set()
     find_candidates = path_exe_finder(spec)
     for pos, path in enumerate(get_paths(env)):
         logging.debug(LazyPathDump(pos, path, env))
         for exe, impl_must_match in find_candidates(path):
-            if exe in tested_exes:
+            exe_raw = str(exe)
+            exe_id = fs_path_id(exe_raw)
+            if exe_id in tested_exes:
                 continue
-            tested_exes.add(exe)
-            interpreter = PathPythonInfo.from_exe(str(exe), app_data, raise_on_error=False, env=env)
+            tested_exes.add(exe_id)
+            interpreter = PathPythonInfo.from_exe(exe_raw, app_data, raise_on_error=False, env=env)
             if interpreter is not None:
                 yield interpreter, impl_must_match
 
@@ -159,7 +180,10 @@ def path_exe_finder(spec):
 
     def path_exes(path):
         # 4. then maybe it's something exact on PATH - if it was direct lookup implementation no longer counts
-        yield (path / direct), False
+        direct_path = path / direct
+        if direct_path.exists():
+            yield direct_path, False
+
         # 5. or from the spec we can deduce if a name on path matches
         for exe in path.iterdir():
             match = pat.fullmatch(exe.name)
diff --git a/src/virtualenv/discovery/py_spec.py b/src/virtualenv/discovery/py_spec.py
index cbfdfb8..04b63b8 100644
--- a/src/virtualenv/discovery/py_spec.py
+++ b/src/virtualenv/discovery/py_spec.py
@@ -70,9 +70,17 @@ class PythonSpec:
         )
         impl = "python" if self.implementation is None else f"python|{re.escape(self.implementation)}"
         suffix = r"\.exe" if windows else ""
+        version_conditional = (
+            "?"
+            # Windows Python executables are almost always unversioned
+            if windows
+            # Spec is an empty string
+            or self.major is None
+            else ""
+        )
         # Try matching `direct` first, so the `direct` group is filled when possible.
         return re.compile(
-            rf"(?P<impl>{impl})(?P<v>{version}){suffix}$",
+            rf"(?P<impl>{impl})(?P<v>{version}){version_conditional}{suffix}$",
             flags=re.IGNORECASE,
         )
 
diff --git a/src/virtualenv/info.py b/src/virtualenv/info.py
index a4fc4bf..dd96f10 100644
--- a/src/virtualenv/info.py
+++ b/src/virtualenv/info.py
@@ -47,11 +47,16 @@ def fs_supports_symlink():
     return _CAN_SYMLINK
 
 
+def fs_path_id(path: str) -> str:
+    return path.casefold() if fs_is_case_sensitive() else path
+
+
 __all__ = (
     "IS_PYPY",
     "IS_CPYTHON",
     "IS_WIN",
     "fs_is_case_sensitive",
+    "fs_path_id",
     "fs_supports_symlink",
     "ROOT",
     "IS_ZIPAPP",
diff --git a/tests/unit/discovery/test_discovery.py b/tests/unit/discovery/test_discovery.py
index 51bae24..6c64b40 100644
--- a/tests/unit/discovery/test_discovery.py
+++ b/tests/unit/discovery/test_discovery.py
@@ -14,7 +14,7 @@ from virtualenv.info import fs_supports_symlink
 
 @pytest.mark.skipif(not fs_supports_symlink(), reason="symlink not supported")
 @pytest.mark.parametrize("case", ["mixed", "lower", "upper"])
-@pytest.mark.parametrize("specificity", ["more", "less"])
+@pytest.mark.parametrize("specificity", ["more", "less", "none"])
 def test_discovery_via_path(monkeypatch, case, specificity, tmp_path, caplog, session_app_data):  # noqa: PLR0913
     caplog.set_level(logging.DEBUG)
     current = PythonInfo.current_system(session_app_data)
@@ -31,7 +31,11 @@ def test_discovery_via_path(monkeypatch, case, specificity, tmp_path, caplog, se
         # e.g. spec: python3.12.1, exe: /bin/python3
         core_ver = ".".join(str(i) for i in current.version_info[0:3])
         exe_ver = current.version_info.major
-    core = f"somethingVeryCryptic{core_ver}"
+    elif specificity == "none":
+        # e.g. spec: python3.12.1, exe: /bin/python
+        core_ver = ".".join(str(i) for i in current.version_info[0:3])
+        exe_ver = ""
+    core = "" if specificity == "none" else f"{name}{core_ver}"
     exe_name = f"{name}{exe_ver}{'.exe' if sys.platform == 'win32' else ''}"
     target = tmp_path / current.install_path("scripts")
     target.mkdir(parents=True)
-- 
2.45.2