From: Geoffrey Thomas Date: Wed, 3 Dec 2014 11:18:11 -0600 Subject: Prevent pip from removing system packages. Adjust is_local() to consider OS-owned paths non-local. Fix the error message for is_local() in the non-virtualenv case. This patch can probably be dropped now that we have PEP-668 support. But we'll keep it for now until we see how things play out with PEP-668. Author: Geoffrey Thomas Bug-Debian: http://bugs.debian.org/771794 Origin: https://github.com/geofft/pip.git Forwarded: not-needed Reviewed-By: Donald Stufft Reviewed-By: Scott Kitterman Last-Update: 2014-12-04 --- src/pip/_internal/utils/misc.py | 34 +++++++++++++++++++++++++++++----- 1 file changed, 29 insertions(+), 5 deletions(-) diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py index baa1ba7..cdf9b3a 100644 --- a/src/pip/_internal/utils/misc.py +++ b/src/pip/_internal/utils/misc.py @@ -321,16 +321,40 @@ def renames(old: str, new: str) -> None: def is_local(path: str) -> bool: """ - Return True if path is within sys.prefix, if we're running in a virtualenv. + Return True if this is a path pip is allowed to modify. - If we're not in a virtualenv, all paths are considered "local." + If we're in a virtualenv, sys.prefix points to the virtualenv's + prefix; only sys.prefix is considered local. + + If we're not in a virtualenv, in general we can modify anything. + However, if the OS vendor has configured distutils to install + somewhere other than sys.prefix (which could be a subdirectory of + sys.prefix, e.g. /usr/local), we consider sys.prefix itself nonlocal + and the domain of the OS vendor. (In other words, everything _other + than_ sys.prefix is considered local.) Caution: this function assumes the head of path has been normalized with normalize_path. """ - if not running_under_virtualenv(): - return True - return path.startswith(normalize_path(sys.prefix)) + + path = normalize_path(path) + # Hard-coded becouse PyPy uses a different sys.prefix on Debian + prefix = '/usr' + + if running_under_virtualenv(): + return path.startswith(normalize_path(sys.prefix)) + else: + from pip._internal.locations import get_scheme + from pip._internal.models.scheme import SCHEME_KEYS + if path.startswith(prefix): + scheme = get_scheme("") + for key in SCHEME_KEYS: + local_path = getattr(scheme, key) + if path.startswith(normalize_path(local_path)): + return True + return False + else: + return True def write_output(msg: Any, *args: Any) -> None: