[Python-checkins] python/dist/src/Misc NEWS,1.1059,1.1060

[tim_one at users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Misc
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv22505/Misc

Modified Files:
	NEWS 
Log Message:
"Core" and "C API" news about new semantics for failing imports.


Index: NEWS
===================================================================
RCS file: /cvsroot/python/python/dist/src/Misc/NEWS,v
retrieving revision 1.1059
retrieving revision 1.1060
diff -C2 -d -r1.1059 -r1.1060
*** NEWS	1 Aug 2004 22:48:06 -0000	1.1059
--- NEWS	2 Aug 2004 03:48:03 -0000	1.1060
***************
*** 13,16 ****
--- 13,36 ----
  -----------------
  
+ - When importing a module M raises an exception, Python no longer leaves M
+   in sys.modules.  Before 2.4a2 it did, and a subsequent import of M would
+   succeed, picking up a module object from sys.modules reflecting as much
+   of the initialization of M as completed before the exception was raised.
+   Subsequent imports got no indication that M was in a partially-
+   initialized state, and the importers could get into arbitrarily bad
+   trouble as a result (the M they got was in an unintended state,
+   arbitrarily far removed from M's author's intent).  Now subsequent
+   imports of M will continue raising exceptions (but if, for example, the
+   source code for M is edited between import attempts, then perhaps later
+   attempts will succeed, or raise a different exception).
+ 
+   This can break existing code, but in such cases the code was probably
+   working before by accident.  In the Python source, the only case of
+   breakage discovered was in a test accidentally relying on a damaged
+   module remaining in sys.modules.  Cases are also known where tests
+   deliberately provoking import errors remove damaged modules from
+   sys.modules themselves, and such tests will break now if they do an
+   unconditional del sys.modules[M].
+ 
  - u'%s' % obj will now try obj.__unicode__() first and fallback to
    obj.__str__() if no __unicode__ method can be found.
***************
*** 142,146 ****
      "%default" in an option's help string is expanded to str() of
      that option's default value, or "none" if no default value.
!     
    - Bug #955889: option default values that happen to be strings are
      now processed in the same way as values from the command line; this
--- 162,166 ----
      "%default" in an option's help string is expanded to str() of
      that option's default value, or "none" if no default value.
! 
    - Bug #955889: option default values that happen to be strings are
      now processed in the same way as values from the command line; this
***************
*** 178,181 ****
--- 198,213 ----
  -----
  
+ - PyImport_ExecCodeModule() and PyImport_ExecCodeModuleEx():  if an
+   error occurs while loading the module, these now delete the module's
+   entry from sys.modules.  All ways of loading modules eventually call
+   one of these, so this is an error-case change in semantics for all
+   ways of loading modules.  In rare cases, a module loader may wish
+   to keep a module object in sys.modules despite that the module's
+   code cannot be executed.  In such cases, the module loader must
+   arrange to reinsert the name and module object in sys.modules.
+   PyImport_ReloadModule() has been changed to reinsert the original
+   module object into sys.modules if the module reload fails, so that
+   its visible semantics have not changed.
+ 
  - A large pile of datetime field-extraction macros is now documented,
    thanks to Anthony Tuininga (patch #986010).