Comment by hahn-kev
18 hours ago
As a non Python dev this seems like very surprising behavior for a system library to be modified by just having a file with a specific name in the same folder.
18 hours ago
As a non Python dev this seems like very surprising behavior for a system library to be modified by just having a file with a specific name in the same folder.
It's an awful problem, and a pretty big gotcha for the ecosystem. For example, I worked on a tool that used `tool_name/random.py` for analysis of RNG usage. However, any command run within that directory would shadow the builtin `import random`. As a result, I couldn't run the `black` formatter from within that directory, because it would accidentally import the local `random.py`.
The solution is to update the python flags to include `-I`, so that python will run in an isolated mode.
<rant>
This is relates to my frustration with how PEP-668 was implemented. Python has long had a problem with accidental overwriting of system libraries. If you `sudo python -mpip install foo`, then that can interact very poorly with your distro's `sudo apt-get install python-foo`, since pip would add/remove files that were expected to be managed solely through `apt-get`.
But in adding a warning to prevent this, they also applied the same warning to `~/.local/pythonX.Y/site-packages`, which is where traditionally a user would install additional packages with `python -mpip --local foo`. The argument is that since this is part of the import path of `/usr/bin/python`, it belongs to the system's python installation, so installation to the user's site-packages should also be blocked. This is a sleight of hand that changes the goal of PEP-668 from "avoid conflicts in file ownership" to "ensure an isolated python environment for system tools".
If I were to accept their argument that /usr/bin/python's imports should only be affected by distro-managed installations, then I should also be prevented from making any `*.py` files anywhere. After all, if those were in the working directory, they would be imported. This is clearly ridiculous, and so I don't buy the argument that breaking user-level site-packages is justified in order to have an isolated system-level python.
The correct solution would be for distro-managed programs to use `#!/usr/bin/python -I` as their shebang instead of `#!/usr/bin/python`, so they would actually get an isolated environment. Instead, PEP-668 needlessly broke user-level site-packages, and didn't even solve the problem that it set out to do.
</rant>
You would get a similar thing in C and C++ with a system header in a library directory (maybe some compilers would warn on such a thing?). Most languages don't privilege their standard libraries in a way that would prevent this.
Privileging the standard library would be a pretty bad way of fixing the issue. It wouldn't prevent the same issue from affecting non-standard libraries, which are also subject to the same issue.
The correct way to avoid this issue would be to require local code to be imported in a distinct manner from installed libraries, with an explicitly defined relative path, which is how it works in the javascript ecosystem. If you want to import local code, you just `import foo from './foo';` (for a module in the same folder, `import foo from '../foo';` for module from parent folder, etc.), and if you want to import an installed library, `import foo from 'foo';`.
Yeah, I wasn't recommending it as a mitigation per se. python /does/ have relative imports but they're not required. C and C++ notionally have a similar thing with "include.h" vs <include.h> but the behavior is complex and not really designed for avoiding confusion about where the header is coming from.
Yeah my takeaway after reading the article was this seems more like a demonstrated vulnerability in Python than in Claude Code.
Yeah my first impression here is just “wow python is bad”