Divergences from pathlib

repopath targets pathlib.Path parity: same method names, signatures, semantics and exception types wherever a pathlib.Path equivalent exists. Extensions (extra optional kwargs, new methods like rm() and copy()) are allowed. Any behavioral divergence from pathlib on a method that exists in both must be listed here -- no silent divergence.

The divergences below apply to GitHubPath, GitLabPath and the URI paths that delegate to them. The ones of the generic Path operations that every path inherits (touch() on a non-local backend, rm() and its policies, chown(), Path.replace(), a with block that raised while writing) are on the documentation site of pathapi, https://jose-pr.github.io/pathapi/divergences/.

Method	pathlib	GitHubPath, GitLabPath	Why
Write methods (mkdir, unlink, rmdir, rename, chmod, open("w"), open("r+"))	pathlib supports all of these	All raise NotImplementedError -- the tree is read-only	Writing to a git repository goes through a commits API (create a commit, not a direct file write) with no filesystem-shaped equivalent: it must specify a commit message and author, and typically targets a new branch.
A relative path, and the empty path	relative to the current working directory	names are read from the root of the repository: x and /x are one file and the empty path is the root	A repository has no working directory, and two spellings of one name must be one file (==, copy() and move() ask).
== and hash()	equal when the path text is	equal when the class, the instance (in any case), the owner, the repository, the ref and the names are; the backend is not part of it	Two refs of one repository are two trees.
str(path)	the file path	the URI: github://instance/owner/repo/path?ref=REF (and gitlab://), which names no token	The text has to say which repository the path is in. as_posix() is the names only.
stat().st_mtime	the file system's modification time	always 0	Neither REST API returns a last-modified time from the call that gives the type and size; it takes a separate, expensive commit-history lookup per path.
is_symlink(), readlink() of a symlink or submodule entry	pathlib exposes links	surfaced as a plain file, no distinction	There is no portable meaning for a submodule (a pointer to another repository, not file content) or a symlink (git stores the link target as the blob content) without extra API calls.
An empty directory (empty_dir/)	pathlib directories can be empty	a directory exists only with a file below it	Git has no empty-directory concept: neither API can return a tree entry for a path with no file under it. This is the repository's property, not a limit of the library.
stat().st_size of a GitLab file in a listing	a stat is complete	a listed file is known to be a file and its size is not known (size_known is False): is_dir()/is_file() answer from the listing, and stat() asks the server for the size	GitLab's tree listing carries no size; guessing one could poison a caller that trusts it.
Names .. and .	PurePath keeps .. lexically	. segments are dropped and .. is kept, but a .. in the path or the ref raises ValueError before any request	A .. in an API URL would be resolved by the client and leave the repository's API root.
A name the service lists that is not one path component (.., a/b, an empty name, one with NUL)	the file system never returns one	left out of iterdir() and _scandir()	A listing is another party's input: such a name must never become a child path.
A Path of another kind joined to a path	joining paths of one flavour is allowed	NotImplementedError from the constructor, TypeError from /	The owner and repository of a GitHub path mean nothing to a GitLab one.
The repo:, github: and gitlab: paths: str(), repr(), as_posix(), as_uri(sanitize=True)	other schemes redact the password only	the whole userinfo is redacted; as_posix() is host:path; as_uri() (unsanitized) still returns it	The token is commonly the bare userinfo (TOKEN@host), the one part other schemes keep, so it reached logs and tracebacks.
gitlab://host/group/sub/project/-/path	N/A	a - segment after the owner and the repository ends the project path, so a project in a subgroup is addressable; a directory called - is written with the separator in front	GitLab's own URL convention; without it only owner/repo projects were addressable.