bpo-39395: Clear env vars set by Python at exit #18078
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Environment variables set by os.environ and os.putenv() are now cleared at exit. Python manages their memory which is released at exit.
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cc @eduardo-elizondo @ericsnowcurrently @serhiy-storchaka @encukou (author and reviewers of PR #10854 and PR #15892). |
| static int | ||
| _posix_clear(PyObject *module) | ||
| { | ||
| Py_CLEAR(_posixstate(module)->billion); | ||
| #ifdef HAVE_UNSETENV | ||
| posix_unset_envvars(_posixstate(module)->posix_putenv_garbage); | ||
| #endif | ||
| Py_CLEAR(_posixstate(module)->posix_putenv_garbage); |
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Given that you are already doing these fixes around this, posix_putenv_garbage should also be guarded by HAVE_PUTENV (check its initialization in the init function).
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Good catch, looks good to me 👍 |
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Should the docs for os.environ and os.putenv be updated to note this explicit deletion? Is it possible that, on some platforms, existing programs might be using the current undefined behavior without crashing and thus might break with this change so it should be documented? |
Yes, it is possible. Python 3.8 was safe: the memory was never released, so environment variables remained available and didn't crash. I will first implement https://bugs.python.org/issue39406 before updating this PR to document the incompatible change. |
serhiy-storchaka
added
needs backport to 3.7
type-bug
This issue is now implemented: os.putenv() is now implemented with setenv() if setenv() is available. So I proposed PR #18135 to fix bpo-39395 differently: on non-Windows platforms, Python now requires setenv() to build. This PR has no backward compatibility issue: it doesn't unset environment variables at exit. |
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I wrote PR #18135 which doesn't introduce a backward incompatible change. I close this PR. |
Environment variables set by os.environ and os.putenv() are now
cleared at exit. Python manages their memory which is released
at exit.
https://bugs.python.org/issue39395