Came across the very same issue that is well described here : https://github.com/wagtail/wagtail/issues/7344#issue-946329708 but the fix doesn't seem to work in my case.
Basically I have a custom ChooserBlock supposed to make it possible to tie a model's given instance to a StructBlock. Rendering works differently if the ChooserBlock value is blank or not, so it is quite important that it actually can be blank.
But when left blank i stamble upon this error when trying to save :
Field 'id' expected a number but got ''.
The error's stack is exactly the same as the one depicted in the github issue I linked above.
I tried the given fix but it doesn't seem to make any difference, at least for my issue.
class CommunityChooserBlock(blocks.ChooserBlock):
target_model = Community
widget = forms.Select
# Return the key value for the select field
def value_for_form(self, value):
if value == "":
return None
else:
return super().value_from_form(value)
Did I miss anything ?
Edit:
I've also tried to override the get_prep_value and clean methods but it didn't change anything.
def get_prep_value(self, value):
if value == '':
return None
else:
super().get_prep_value(value)
def clean(self, value):
if value == '':
value = None
super().clean(value)
Update : I couldn't come up with a proper fix, so I changed my plans and went for a ChoiceBlock with dynamic choices list, as described here : https://stackoverflow.com/a/60979072/13934028.
It seems to work just fine for my case