[issue25641] urllib/request.py/getproxies_environment() throws "dictionary changed size during iteration" error occasionally

[alphalfalfa]

New submission from alphalfalfa:

For the following lines of code, "dictionary changed size during iteration" would be thrown when the environment variables change while in iteration.

Python-3.5.0/Lib/urllib/request.py
2393     for name, value in os.environ.items():
2394         name = name.lower()
2395         if value and name[-6:] == '_proxy':
2396             proxies[name[:-6]] = value

----------
components: Library (Lib)
messages: 254767
nosy: alphalfalfa
priority: normal
severity: normal
status: open
title: urllib/request.py/getproxies_environment() throws "dictionary changed size during iteration" error occasionally
versions: Python 3.4, Python 3.5

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue25641>
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