Move pathlib compatibility code to dedicated module

`piptools._compat.path_compat` is a new module for holding any helpers
dedicated to path inspection and manipulations.

Author: sirosen

piptools/_compat/path_compat.py

@@ -0,0 +1,33 @@
+"""
+Compatibility helpers for working with paths and ``pathlib`` across platforms
+and Python versions.
+"""
+import os.path
+import pathlib
+import sys
+
+
+def relative_to_walk_up(path: pathlib.Path, start: pathlib.Path) -> pathlib.Path:
+    """
+    Compute a relative path allowing for the input to not be a subpath of the start.
+
+    This is a compatibility helper for ``pathlib.Path.relative_to(..., walk_up=True)``
+    on all Python versions. (``walk_up: bool`` is Python 3.12+)
+    """
+    # prefer `pathlib.Path.relative_to` where available
+    if sys.version_info >= (3, 12):
+        return path.relative_to(start, walk_up=True)
+
+    str_result = os.path.relpath(path, start=start)
+    return pathlib.Path(str_result)
+
+
+def is_path_relative_to(path1: pathlib.Path, path2: pathlib.Path) -> bool:
+    """Return True if ``path1`` is relative to ``path2``."""
+    # TODO: remove this function in favor of Path.is_relative_to()
+    #       when we drop support for Python 3.8
+    try:
+        path1.relative_to(path2)
+    except ValueError:
+        return False
+    return True

piptools/_compat/pip_compat.py

@@ -1,9 +1,7 @@
 from __future__ import annotations
 
 import optparse
-import os.path
 import pathlib
-import sys
 import urllib.parse
 from dataclasses import dataclass
 from typing import TYPE_CHECKING, Callable, Iterable, Iterator, Set, cast
@@ -20,6 +18,8 @@
 from pip._internal.req.constructors import install_req_from_parsed_requirement
 from pip._vendor.pkg_resources import Requirement
 
+from .path_compat import relative_to_walk_up
+
 # The Distribution interface has changed between pkg_resources and
 # importlib.metadata, so this compat layer allows for a consistent access
 # pattern. In pip 22.1, importlib.metadata became the default on Python 3.11
@@ -154,7 +154,7 @@ def _relativize_comes_from_location(original_comes_from: str, /) -> str:
         return f"{prefix} {file_path.as_posix()}"
 
     # make it relative to the current working dir
-    suffix = _relative_to_walk_up(file_path, pathlib.Path.cwd()).as_posix()
+    suffix = relative_to_walk_up(file_path, pathlib.Path.cwd()).as_posix()
     return f"{prefix}{space_sep}{suffix}"
 
 
@@ -212,18 +212,3 @@ def get_dev_pkgs() -> set[str]:
     from pip._internal.commands.freeze import _dev_pkgs
 
     return cast(Set[str], _dev_pkgs())
-
-
-def _relative_to_walk_up(path: pathlib.Path, start: pathlib.Path) -> pathlib.Path:
-    """
-    Compute a relative path allowing for the input to not be a subpath of the start.
-
-    This is a compatibility helper for ``pathlib.Path.relative_to(..., walk_up=True)``
-    on all Python versions. (``walk_up: bool`` is Python 3.12+)
-    """
-    # prefer `pathlib.Path.relative_to` where available
-    if sys.version_info >= (3, 12):
-        return path.relative_to(start, walk_up=True)
-
-    str_result = os.path.relpath(path, start=start)
-    return pathlib.Path(str_result)

piptools/utils.py

@@ -37,6 +37,7 @@
 from pip._vendor.packaging.version import parse as parse_version
 from pip._vendor.pkg_resources import get_distribution
 
+from piptools._compat.path_compat import is_path_relative_to
 from piptools.locations import DEFAULT_CONFIG_FILE_NAMES
 from piptools.subprocess_utils import run_python_snippet
 
@@ -757,14 +758,3 @@ def _normalize_config_key(key: str) -> str:
 def _convert_to_long_option(key: str) -> str:
     """Transform given ``some-key`` into ``--some-key``."""
     return "--" + key.lstrip("-").replace("_", "-").lower()
-
-
-def is_path_relative_to(path1: Path, path2: Path) -> bool:
-    """Return True if ``path1`` is relative to ``path2``."""
-    # TODO: remove this function in favor of Path.is_relative_to()
-    #       when we drop support for Python 3.8
-    try:
-        path1.relative_to(path2)
-    except ValueError:
-        return False
-    return True