pathlib2

pathlib2 is a backport of Python’s standard library pathlib module, providing object-oriented filesystem path handling for versions of Python that predate or lag behind the reference implementation. It began as a fork of the original, now-unmaintained pathlib project and has since tracked upstream CPython’s pathlib development, porting newer standard-library features back to older runtimes so codebases pinned to legacy interpreters can still use the modern Path API.

The library exposes the same PurePath/Path class hierarchy as the stdlib version — PurePosixPath, PureWindowsPath, PosixPath, and WindowsPath — with platform-specific flavour objects handling parsing, globbing, and path normalization differences between POSIX and Windows. Maintained under the Jazzband collective, it targets recent Python 3 releases and is primarily useful for projects that need the newest pathlib behavior without waiting for their runtime to catch up, or for tooling that must remain compatible with a wider range of interpreter versions than the standard library alone supports.

What You Get

• The full PurePath/Path class hierarchy (PurePosixPath, PureWindowsPath, PosixPath, WindowsPath) mirroring the standard library’s own API
• Platform-specific flavour objects that isolate POSIX and Windows path parsing and normalization differences
• Backported behavior from newer CPython pathlib releases, usable on older supported interpreters
• A drop-in replacement import (import pathlib2 as pathlib) for codebases needing consistent path behavior across Python versions
• A maintained test suite covering parsing, globbing, and OS-specific edge cases including unicode filenames

Common Use Cases

• Supporting a wider range of Python versions in a library while relying on the newest pathlib features
• Backfilling pathlib bug fixes and behavior changes into environments stuck on an older interpreter
• Providing consistent path-handling behavior across a cross-version test matrix
• Migrating legacy codebases toward a pathlib-based API ahead of a full interpreter upgrade

Under The Hood

Architecture pathlib2 concentrates its class hierarchy in a single core module, implementing a base flavour class plus platform-specific POSIX/Windows flavour subclasses, and the familiar PurePath/Path/PosixPath/WindowsPath hierarchy from CPython’s own pathlib. Platform differences are isolated into separate posix and Windows helper modules imported conditionally by operating system, keeping the core parsing and I/O logic OS-agnostic. Path construction flows through the flavour’s part-parsing routine, which tokenizes drive/root/parts into an immutable PurePath, while the Path subclass layers on I/O operations (stat, glob, open) that delegate to os/os.path calls guarded against known platform-specific error codes. Because pathlib2 is deliberately a backport rather than an original design, its architecture mirrors stdlib pathlib closely — what would break if the core flavour-parsing abstraction changed is exactly what would break in the standard library itself.

Tech Stack The library has zero runtime dependencies, built entirely on the Python standard library (os, posixpath, ntpath, stat, errno, fnmatch, urllib.parse). Packaging uses classic setuptools with a src-layout, and continuous integration runs the test suite across multiple operating systems and a broad range of supported Python versions, also enforcing linting and static type checking alongside a Sphinx-built documentation site.

Code Quality The project ships an extensive test suite built on Python’s unittest framework, including OS-specific tests that exercise platform-only code paths and dedicated coverage for unicode filename handling. Error handling is deliberate rather than defensive — a centralized error-ignoring helper enumerates the specific OS error codes considered safe to ignore during path resolution, rather than broadly swallowing exceptions. Type hints appear on core class attributes and the codebase is checked with a static type checker, and linting runs as part of continuous integration. Naming conventions consistently follow the standard library’s own pathlib style.

API Design Because pathlib2’s public API mirrors the standard library’s pathlib almost exactly, developers already familiar with stdlib pathlib face effectively no learning curve — adopting it typically requires only a single import substitution. Class and method naming is fully consistent with CPython conventions, and documentation intentionally defers to the official pathlib reference rather than duplicating it, keeping the library lightweight at the cost of needing to cross-reference two docs sources for version-specific caveats. Getting started requires no configuration beyond the import itself.