Actually, the traceback says what's happening is CookHeaders is trying to create the List-Id: header to be added to the message. It tries to create a header of the form: List-Id: list description <list.example.com> And the exception occurs when trying to rfc 2047 encode the list's description in the charset of the list's preferred language. This exception should be occurring on every list post. Is that the case? Also, what is the list's preferred_language and what is the raw value of the list's description attribute. Obtain this info with something like: $ bin/withlist list1 Loading list list1 (unlocked) The variable `m' is the list1 MailList instance

...

...

m.preferred_language 'en' m.description 'My List one'

(of course the list name and responses will be different in your case.) ** Changed in: mailman Importance: Undecided => Medium ** Changed in: mailman Status: New => Incomplete ** Changed in: mailman Milestone: None => 2.1.21 ** Changed in: mailman Assignee: (unassigned) => Mark Sapiro (msapiro) -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1462755 Title: qrunner crashes on invalid unicode sequence To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1462755/+subscriptions

It appears the underlying issue is someone has changed Mailman's character set for 'nl' (Dutch) from iso-8859-1 to utf-8. Possibly whoever did this did the appropriate things such as recoding the message catalog and templates to utf-8, but in any case, the strings in the attributes of this list weren't recoded. This is one of the major problems that make it difficult to change Mailman's encoding for a language. See the definitions of the recode(), doitem() and convert() functions in Mailman/versions.py in Mailman 2.1.19 or later. So basically, this issue appears to be a 'shot oneself in the foot' thing and probably could be fixed by setting the list's description to 'Lijst voor Caljent\xc3\xa9-leden', although I would be concerned that there are other iso-8859-1 strings in list attributes. Anyway, I see this as an issue worth fixing. The fix I would propose is in Mailman/Handlers/CookHeaders.py replace the line at the end of the definition of uheader which is currently return Header(s, charset, maxlinelen, header_name, continuation_ws) with try: return Header(s, charset, maxlinelen, header_name, continuation_ws) except UnicodeError: syslog('error', 'list: %s: can\'t decode "%s" as %s', mlist.internal_name(), s, charset) return Header('', charset, maxlinelen, header_name, continuation_ws) ** Changed in: mailman Importance: Medium => Low ** Changed in: mailman Status: Incomplete => In Progress -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1462755 Title: qrunner crashes on invalid unicode sequence To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1462755/+subscriptions

** Changed in: mailman Status: In Progress => Fix Committed -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1462755 Title: qrunner crashes on invalid unicode sequence To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1462755/+subscriptions

Actually, IncomingRunner doesn't actually "crash"; it does encounter an unanticipated exception causing it to log the exception and shunt the message, and yes, the underlying issue is definitely a "misconfiguration", but catching the exception and dealing with it more gracefully without shunting the message wasn't hard, so I thought it worthwhile. -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1462755 Title: qrunner crashes on invalid unicode sequence To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1462755/+subscriptions

For more information on the causes of this issue and the fallout from what turns out to be Debian's changing of the character set for several languages, see the thread "Encoding problem with 2.15 to 2.18 upgrade with Finnish" beginning at <https://mail.python.org/pipermail/mailman- users/2015-December/080221.html> and continuing at <https://mail.python.org/pipermail/mailman- users/2016-January/080275.html>. There is a script mentioned in that thread at <https://www.msapiro.net/scripts/recode_list> (mirrored at <http://fog.ccsf.edu/~msapiro/scripts/recode_list>) that can programmatically recode the strings in a list's configuration to "fix" this issue. -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1462755 Title: qrunner crashes on invalid unicode sequence To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1462755/+subscriptions

Setting the task for a whishlist item, since it is essentially a config change that breaks it (as Mark said 'shot oneself in the foot'. I'm personally not so keen about on-upgrade detection+warning since that (in general) has a history of too many false-positives leading people to config-break their system without a reason. But then as I read Mark this is due to Debian intentionally changing some encodings, so maybe it should be done ... ** Changed in: mailman (Ubuntu) Status: New => Confirmed ** Changed in: mailman (Ubuntu) Importance: Undecided => Wishlist -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1462755 Title: qrunner crashes on invalid unicode sequence To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1462755/+subscriptions