[Mailman-Users] Upgrading/migrating Mailman v2.1.9 -> v2.1.18-1

Mark Sapiro mark at msapiro.net
Thu Jan 15 07:25:23 CET 2015

On 01/14/2015 09:50 PM, Chris Nulk wrote:
> On Wed, Jan 14, 2015 at 7:03 PM, Mark Sapiro <mark at msapiro.net> wrote:
>> in 2.1.18-1, DATA_FILE_VERSION is already 104. The only reason to
>> increment DATA_FILE_VERSION is so versions.Update() will run when an
>> older list in first instantiated. Since your changes were made at
>> DATA_FILE_VERSION = 97, there's no point in incrementing
>> DATA_FILE_VERSION beyond 104.
> ​Hmmm.  I have already changed it to 105, restarted Mailman, and created a
> couple of lists to test.  Is there any harm with deleting the lists,
> backing out the change, and restarting Mailman?

No, there's no problem with that. In fact it would be best as it
relieves you of the need to keep incrementing it.

Consider that if you leave yours at 105, and then I make a change which
increments mine to 105, you have to increment yours to 106 to pick up my
change on your existing lists. Better to leave yours at 104.

You do need to be sure that you have code in MailList.py in the InitVars
method to initialize your attribute for new lists.

The only way you would run into difficulty with not incrementing
DATA_FILE_VERSION beyond 104 would be if you moved a 2.1.18 or later
list's config.pck to your Mailman from another Mailman that didn't have
your changes, but I think it unlikely that you would do that, and if you
did, you could use withlist to either set the data_version attribute to
say 103 (which would then magically update the list and set it back to
104) or to add your new attribute manually.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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