CodeVetter · Repo Unpack · Risk map
psf/requests
As a library in ~4M dependent repos, the blast radius of any change here is close to maximal, and the highest-risk surfaces are the ones that decide whether credentials cross a trust boundary: `should_strip_auth`, `rebuild_proxies`, `prepare_url`, and `cert_verify`. Several behaviours are knowingly non-ideal and preserved for backwards compatibility — the http→https auth-retention carve-out, `_basic_auth_str` accepting non-strings, and `LookupDict.__getitem__` silently returning `None`. Environment trust is on by default (`trust_env=True`), so `.netrc`, `$NETRC`, `REQUESTS_CA_BUNDLE`/`CURL_CA_BUNDLE` and `*_proxy` variables all influence behaviour implicitly. Filesystem and process-global side effects exist in `extract_zipped_paths`, `atomic_open`, `set_environ`, and the import-time `pyopenssl.inject_into_urllib3()`.
- `should_strip_auth` intentionally keeps the `Authorization` header across an http:80 → https:443 redirect on the same host; the comment states this is not RFC 7235 behaviour and is retained only for backwards compatibility.
- `rebuild_proxies` reconstructs `Proxy-Authorization` from proxy URL credentials but skips it when the target scheme starts with `https`, explicitly to avoid leaking the header into a TLS tunnel — a subtle invariant easy to break in a refactor.
- Any URL containing a colon whose scheme does not start with `http` bypasses all URL preparation and is assigned verbatim to `self.url`, so `mailto:`/`data:`-style inputs skip IDNA, requoting and host validation entirely.
- `verify=False` disables certificate and hostname validation at the urllib3 level (`cert_reqs = 'CERT_NONE'`, ca_certs cleared); the Session docstring is explicit that this exposes callers to MitM and is for testing only.
- `trust_env=True` by default means an attacker-controlled or accidentally-set `REQUESTS_CA_BUNDLE`/`CURL_CA_BUNDLE` silently replaces the trust store for every request on the session.
- `get_netrc_auth` reads credentials from a path taken from the `$NETRC` environment variable without restriction, and swallows `NetrcParseError`/`OSError` unless `raise_errors=True` — failures to read credentials are silent by default.
- `extract_zipped_paths` performs file IO outside the repo root: it walks a path upward looking for a zip archive, then extracts a member into a `tempfile.mkstemp()` file that is never cleaned up, returning that path to the caller.
- `_basic_auth_str` still accepts non-string usernames/passwords, coercing them with a `DeprecationWarning` promising removal in 3.0.0; the source comment preserves it precisely because callers depend on it.
- Digest auth uses MD5 by default when the server omits an `algorithm` directive; MD5/SHA-1 usage is flagged `usedforsecurity=False` to appease FIPS builds but the weak-hash negotiation is server-driven.
- `handle_401` re-sends the authenticated request directly through `r.connection.send(prep, **kwargs)`, bypassing `Session.send` — so session-level cookie extraction, hooks, and redirect resolution do not run for that hop.
- `prepare_auth` blanket-applies `self.__dict__.update(r.__dict__)` from a user-supplied callable, meaning a third-party auth class can overwrite any attribute of the PreparedRequest including `url` and `hooks`.
- `LookupDict.__getitem__` deliberately falls through to `None` for unknown keys, so a typo'd `requests.codes['okey']` silently yields `None` instead of raising — a footgun with no test-enforced guard.
- `HTTPAdapter.get_connection` is live deprecated code retained for subclass compatibility; it emits a `DeprecationWarning` and, unlike `get_connection_with_tls_context`, does not incorporate verify/cert into the pool key.
- `compat.py` is largely legacy: it still exports `is_py2`, `is_py3`, `basestring`, `numeric_types` and `integer_types` for a Python 2 that the project no longer supports (`requires-python = ">=3.10"`), and shadows the builtin `str`/`bytes` names.
- `packages.py` mutates the global `sys.modules` table at import time to alias urllib3/idna/chardet under `requests.packages.*` — a process-wide side effect purely for pre-2.16 backwards compatibility.
- `.coveragerc` omits `requests/packages/*`, a path that no longer exists since the move to `src/` layout, so the omit rule is dead configuration. (inferred)
- Release-critical files are protected by CODEOWNERS requiring lead-maintainer review: `.github/workflows/`, `src/requests/__version__.py`, `HISTORY.md` and `pyproject.toml`.