Jim Jewett <jimjjew...@gmail.com> added the comment: > I have a lock that may or may not be currently held when I release it, > and now I know I can just catch RuntimeError in that case.
Only if you're willing to make assumptions about the threading model and the source of locks. And I fear the current change overpromises. For example, the LockType from _dummy_thread raises an error not based on RuntimeError, and has comments suggesting it might stop raising entirely. I believe I have seen other Lock-emulation code which also does not raise an error, though the closest I can come to finding it right now is logging_releaseLock() when the import of either _thread or threading failed. Starting with http://hg.python.org/cpython/file/acea9d95a6d8/Doc/library/threading.rst I would prefer to change to following two sentences: If an attempt is made to release an unlocked lock, a :exc:`RuntimeError` will be raised. ... When invoked on an unlocked lock, a :exc:`ThreadError` is raised. in any of the following ways: (a) Change "will be"/"is" --> "may be", so it isn't promised: If an attempt is made to release an unlocked lock, a :exc:`RuntimeError` may be raised. ... When invoked on an unlocked lock, a :exc:`ThreadError` may be raised. (b) Clarify that it is implementation-specific If an attempt is made to release an unlocked _thread.lock, a :exc:`RuntimeError` will be raised. ... When invoked on an unlocked _thread.lock, a :exc:`ThreadError` is raised. (and add to the caveats) Locks provided by other modules may have slightly different behavior, particularly when an an operation fails. For example, unlocking without first acquiring may raise a different error, or may not raise at all. (c) Clarify that alternatives are buggy (and fix those in the stdlib) If an attempt is made to release an unlocked lock, a :exc:`RuntimeError` will be raised. ... When invoked on an unlocked lock, a :exc:`ThreadError` is be raised. (and add to the caveats) Historically, many Locks have followed a slightly different contract, particularly when an an operation fails. For example, unlocking without first acquiring might raise a different error, or might not even raise at all. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue14502> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
