Preconditions/Environment
-------------------------
Debian-9
Latest github.com:openembedded/openembedded, master or rocko branches
Bitbake 1.32, 134, or 1.36 (bitbake dir as a symlink in oe-core directory)

Any oe-core on or after commit 7267e7c000c76c44d09835d4cd2bc485b6a39a2a
triggers this error for me.

Triggering Action/Cause
-----------------------
git clone git://git.openembedded.org/bitbake
git clone git://github.com/openembeded/openembedded
cd openembedded
ln -s ../bitbake .
. ./oe-init-env
bitbake -c listtasks
(other bitbake actions also fail, this is just a simple test case)

Expectation
-----------
Should get 'Nothing to do.  Use 'bitbake world' to build everything, or run 'bitbake --help' for usage information.'

Actual Result
-------------
Get

ERROR: Execution of event handler 'base_eventhandler' failed
Traceback (most recent call last):
  File "/home/cshoredaniel/Build/firmware/openembedded/oe-core-error/meta/classes/base.bbclass", line 231, in
base_eventhandler(e=<bb.event.ConfigParsed object at 0x7f483d66c1d0>):

    >    if isinstance(e, bb.event.MultiConfigParsed):
             # We need to expand SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS in each of the multiconfig data stores
AttributeError: module 'bb.event' has no attribute 'MultiConfigParsed'

ERROR: Error parsing configuration files
Traceback (most recent call last):
  File "/home/cshoredaniel/Build/firmware/openembedded/bitbake/lib/bb/cookerdata.py", line 274, in CookerDataBuilder.parseBaseConfiguration():

    >            bb.event.fire(bb.event.ConfigParsed(), self.data)

  File "/home/cshoredaniel/Build/firmware/openembedded/bitbake/lib/bb/event.py", line 211, in fire(event=<bb.event.ConfigParsed object at 0x7f483d66c1d0>, d=<bb.data_smart.DataSmart object at 0x7f483daf0cf8>):

    >    fire_class_handlers(event, d)
         if worker_fire:
  File "/home/cshoredaniel/Build/firmware/openembedded/bitbake/lib/bb/event.py", line 134, in fire_class_handlers(event=<bb.event.ConfigParsed object at 0x7f483d66c1d0>, d=<bb.data_smart.DataSmart object at 0x7f483daf0cf8>):
                         continue
    >            execute_handler(name, handler, event, d)

  File "/home/cshoredaniel/Build/firmware/openembedded/bitbake/lib/bb/event.py", line 106, in execute_handler(name='base_eventhandler', handler=<function base_eventhandler at 0x7f483d20bb70>, event=<bb.event.ConfigParsed object at 0x7f483d66c1d0>, d=<bb.data_smart.DataSmart object at 0x7f483daf0cf8>):
         try:
    >        ret = handler(event)
         except (bb.parse.SkipRecipe, bb.BBHandledException):
  File "/home/cshoredaniel/Build/firmware/openembedded/oe-core-error/meta/classes/base.bbclass", line 231, in
base_eventhandler(e=<bb.event.ConfigParsed object at 0x7f483d66c1d0>):

    >    if isinstance(e, bb.event.MultiConfigParsed):
             # We need to expand SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS in each of the multiconfig data stores
AttributeError: module 'bb.event' has no attribute 'MultiConfigParsed'


Reproducibility
---------------
always with commits on or after 7267e7c000c76c44d09835d4cd2bc485b6a39a2a

I did a git bisect with an old commit as known good (f43290f6e302dbacf5581d1fe1c6c991dd387779) and current master HEAD (5e5569c962c9ebc898eeb5044214e95117b190e1) as bad, and narrowed it down to a single commit (7267e7c000c76c44d09835d4cd2bc485b6a39a2a) as the where the error begins occurring.