(backport from rev. 53522)

Patch #1464708 from William McVey: fixed handling of nested comments in mail
addresses.  E.g.

"Foo ((Foo Bar)) <foo@example.com>"

Fixes for both rfc822.py and email package.  This patch needs to be back
ported to Python 2.3 for email 2.5.

* Use +=
* Replace loop logic with str.splitlines equivalent
* Don't use variable names that shadow tuple, list, and str
* Use dict.get instead of equivalent try/except
* Minor loop logic simplications

Add iteration support to the Message class.

Specifically, time.strftime() no longer accepts a 0 in the yday position of a
time tuple, since that can crash some platform strftime() implementations.

parsedate_tz(): Change the return value to return 1 in the yday position.

Update tests in test_rfc822.py and test_email.py

Quinn Dunkan's mimelib SF patch #573204) fixes the problem.

Change default for get() back to None.
Will backport to 2.2.1.

fixed (re: SF bug #555035).  Include a unittest.

instead of calling the getaddrlist() method, since the latter doesn't
work with multiple calls (it will return the empty list for the second
and subsequent calls).

Closes SF bug #555035.  Include a unittest.

    rfc822.AddressList incorrectly handles empty address.
    "<>" is converted to None and should be "".
    AddressList.__str__() fails on None.
    I got an email with such an address and my program
    failed processing it.

    Example:
    >>> import rfc822

    >>> rfc822.AddressList("<>").addresslist
    [('', None)]
    >>> str(rfc822.AddressList("<>"))
    Traceback (most recent call last):
    File "<stdin>", line 1, in ?
    File "/usr/lib/python2.1/rfc822.py", line 753, in __str__
    return ", ".join(map(dump_address_pair,
    self.addresslist))
    TypeError: sequence item 0: expected string, None found

[His solution: in the internal routine AddrlistClass.getrouteaddr(),
initialize adlist to "".]

IndexError when a Date: field exists with an empty value.

mostly changes of / operators into //.  Once or twice I did more or
less than recommended.

Modify rfc822.formatdate() to always generate English names,
regardless of locale.  This is required by RFC 1123.

In open_local_file() of urllib and urllib2, use new formatdate() from
rfc822.

#437395

now allowed in unquoted RealName areas (technically, they are defined
as "obsolete syntax" we MUST accept in phrases, as part of the
obs-phrase production).  Thus, parsing

    To: User J. Person <person@dom.ain>

correctly returns "User J. Person" as the RealName.

AddrlistClass.__init__(): Add definition of self.phraseends which is
just self.atomends with `.' removed.

getatom(): Add an optional argument `atomends' which, if None (the
default) means use self.atomends.

getphraselist(): Pass self.phraseends to getatom() and break out of
the loop only when the current character is in phraseends instead of
atomends.  This allows dots to continue to serve as atom delimiters in
all contexts except phrases.

Also, loads of docstring updates to document RFC 2822 conformance
(sorry, this should have been two separate patches).

setdefault() the empty string.  In setdefault(), use + to join the value
to create the entry for the headers attribute so that TypeError is raised
if the value is of the wrong type.

also modified check_all function to suppress all warnings since they aren't
relevant to what this test is doing (allows quiet checking of regsub, for
instance)

and isdigit() methods.

string.digits are left.

try/except.

literal be wrapped in square brackets.  This fix replaces the square
brackets that were previously being stripped off.  Closes SF bug
#110621.

rfc822 (Addresslist) modules. Also a preliminary testcase for augmented
assignment, which should actually be merged with the test_class testcase I
added last week.

comments, docstrings or error messages. I fixed two minor things in
test_winreg.py ("didn't" -> "Didn't" and "Didnt" -> "Didn't").

There is a minor style issue involved: Guido seems to have preferred English
grammar (behaviour, honour) in a couple places. This patch changes that to
American, which is the more prominent style in the source. I prefer English
myself, so if English is preferred, I'd be happy to supply a patch myself ;)

ParsedDate didn't have the correct day of week.

colon, the first character of the value is lost.

It breaks Mailman, it was actually documented in the docstring, so it
was an intentional deviation from the usual del semantics.  Let's
document the original behavior in Doc/lib/librfc822.tex.