Jeff Allen <ja...@farowl.co.uk> added the comment:
I'm interested in Thomas' reasons, but here are some of mine (as far as I understand things): 1. It is specific to one interpreter implemented in C, equipped with a GIL, and on certain assumptions about the byte code interpreter and the implementation of built-ins, that may not hold long-term. 2. In x = L[i], the index and assignment are distinct actions (in today's byte code), allowing L or i to change before x is assigned. This applies to multiple other of the examples. 3. A compiler (even a CPU) is free to re-order operations and cache values in unguessable ways, on the assumption of a single thread. 4. Code written on these principals is fragile. It only takes the replacement of a built-in with sub-class redefining __getitem__ (to support some worthy aim elsewhere in the code) to invalidate it. 5. sort() is not atomic if an element is of a type that overrides comparison in Python. (Nor is modifying a dictionary if __hash__ or __eq__ are redefined.) If you want retain the question, with a better answer, the last sentence is good: "When in doubt, use a mutex!", accompanied by "Always be in doubt." ---------- nosy: +jeff.allen _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue45435> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
