[Zope] ZEO manageUndo not working - DisconnectedError

[Tino Wildenhain]

Hi Sebastian,

Am 06.05.2015 um 15:26 schrieb Sebastian Tänzer:
 > After further testing I was able to sort this one out by downgrading 
ZopeUndo to 2.12.0 (pip install ZopeUndo==2.12.0 --force —upgrade).
 > PyPi only said 4.0 brought Py3 compability. Should I expect any 
problems using ZopeUndo 2.12 + ZEO/ZODB4/ZODB3 with their latest versions?
 >

Undo has long been a standard functionality in Zope2 but proven to be
quite dangerous as it is possible to totally mess up your object
tree.

IIRC undo has therefore been removed even from the ZODB - that is
what you are experiencing with the current version.

What seems to work quite well is to enable history support where you
have access to every old transaction and can compare or copy them
to be on top of the stack - which avoids the problem with disappearing
transactions as Undo has.

Unfortunately out of the box only a few Products have history support
enabled. Some monkey patching can enable it for many of the other
Products of stock Zope2. ObjectManager/Folder is a bit limited
since accessing a whole historic version of a subtree can't be done
easily. However, if you are interested and want to try:

http://old.zope.org/Members/tino/PatchHistory/view

(very old, but seems to work with the 2.12 at least)

Best,
Tino

> Best, Sebastian