- fix broken assert statement; should just raise

have differing refcount semantics.  If anyone sees a prettier way to
acheive the same ends, then please go for it.

I think this is the first time I've ever used Py_XINCREF.

(or to whatever the 'insert' method chose to return).

must have annoyed me at some point.

* Fixes an incorrect variable in a PyDict_CheckExact.
* Allow general mapping locals arguments for the execfile() function
  and exec statement.
* Add tests.

"@ seems the syntax that everybody can hate equally"
Implementation by Mark Russell, from SF #979728.

after a failed import.

This is the last checkin in the "change import failure semantics" series.

    test_failing_import_sticks -- if an import raises an exception,
        ensure that trying to import it again continues raising exceptions
    test_failing_reload -- if a module loads OK, but a reload raises an
        exception, ensure that the module is still in sys.modules, and
        that its __dict__ reflects as much of the reload attempt as
        succeeded.  That doesn't seem like sane semantics, but it is
        backward-compatible semantics <wink>.

getting left beyind in sys.modules.

PyImport_ReloadModule():  restore the module to sys.modules in error cases.
load_package():  semantic-neutral refactoring from an earlier stab at
                 this patch; giving it a common error exit made the code
                 easier to follow, so retaining that part.
_RemoveModule():  new little utility to delete a key from sys.modules.

in failure cases, incompletely initalized module objects are no longer
left behind in sys.modules.

already correct, so not changed here.

Backport candidate.

Backport candidate.

of no more than 8 elements cannot fail.

listpop():  Take advantage of that its calls to list_resize() and
list_ass_slice() can't fail.  This is assert'ed in a debug build now, but
in an icky way.  That is, you can't say:

	assert(some_call() >= 0);

because then some_call() won't occur at all in a release build.  So it
has to be a big pile of #ifdefs on Py_DEBUG (yuck), or the pleasant:

        status = some_call();
        assert(status >= 0);

But in that case, compilers may whine in a release build, because status
appears unused then.  I'm not certain the ugly trick I used here will
convince all compilers to shut up about status (status is always "used" now,
as the first (ignored) clause in a comma expression).

This fixes 15 spurious test failures on Windows (probably all due to
the test leaving a wrong path in sys.argv[0], which then prevented
regrtest.py from finding the expected-output files for tests running
after test_optparse).

  * add expansion of default values in help text: the string
    "%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
    allows generation of nicer help when using custom types.  Can
    be disabled with parser.set_process_default_values(False).
  * bug #960515: don't crash when generating help for callback
    options that specify 'type', but not 'dest' or 'metavar'.
  * feature #815264: change the default help format for short options
    that take an argument from e.g. "-oARG" to "-o ARG"; add
    set_short_opt_delimiter() and set_long_opt_delimiter() methods to
    HelpFormatter to allow (slight) customization of the formatting.
  * patch #736940: internationalize Optik: all built-in user-
    targeted literal strings are passed through gettext.gettext().  (If
    you want translations (.po files), they're not included with Python
    -- you'll find them in the Optik source distribution from
    http://optik.sourceforge.net/ .)
  * bug #878453: respect $COLUMNS environment variable for
    wrapping help output.
  * feature #988122: expand "%prog" in the 'description' passed
    to OptionParser, just like in the 'usage' and 'version' strings.
    (This is *not* done in the 'description' passed to OptionGroup.)

impossible to remember, so renamed one to something obvious.  Headed
off potential signed-vs-unsigned compiler complaints I introduced by
changing the type of a vrbl to unsigned.  Removed the need for the
tedious explanation about "backward pointer loops" by looping on an
int instead.

result.

list_resize():  Document the intent.  Code is increasingly relying on
subtle aspects of its behavior, and they deserve to be spelled out.

list_ass_slice():  A bit more simplification, by giving it a common
error exit and initializing more values.

Be clearer in comments about what "size" means (# of elements?  # of
bytes?).

While the number of elements in a list slice must fit in an int, there's
no guarantee that the number of bytes occupied by the slice will.  That
malloc() and memmove() take size_t arguments is a hint about that <wink>.
So changed to use size_t where appropriate.

ihigh - ilow should always be >= 0, but we never asserted that.  We do
now.

The loop decref'ing the recycled slice had a subtle insecurity:  C doesn't
guarantee that a pointer one slot *before* an array will compare "less
than" to a pointer within the array (it does guarantee that a pointer
one beyond the end of the array compares as expected).  This was actually
an issue in KSR's C implementation, so isn't purely theoretical.  Python
probably has other "go backwards" loops with a similar glitch.
list_clear() is OK (it marches an integer backwards, not a pointer).

- document the use of the return value for cmd.Cmd.do_*() methods