From: Antoine Pitrou Date: Thu, 17 May 2012 19:13:45 +0000 (+0200) Subject: Add a mention of the new import locks in whatsnew. X-Git-Tag: v3.3.0a4~139 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=79341e7865db69ec4f056c7d274aec06bf58a16f;p=python Add a mention of the new import locks in whatsnew. --- diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst index 6fb60afdb9..fe1a84a2ce 100644 --- a/Doc/whatsnew/3.3.rst +++ b/Doc/whatsnew/3.3.rst @@ -573,6 +573,23 @@ Some smaller changes made to the core Python language are: .. XXX mention new error messages for passing wrong number of arguments to functions +A Finer-Grained Import Lock +=========================== + +Previous versions of CPython have always relied on a global import lock. +This led to unexpected annoyances, such as deadlocks when importing a module +would trigger code execution in a different thread as a side-effect. +Clumsy workarounds were sometimes employed, such as the +:c:func:`PyImport_ImportModuleNoBlock` C API function. + +In Python 3.3, importing a module takes a per-module lock. This correctly +serializes importation of a given module from multiple threads (preventing +the exposure of incompletely initialized modules), while eliminating the +aforementioned annoyances. + +(contributed by Antoine Pitrou in :issue:`9260`.) + + New and Improved Modules ========================