ValidationError crashes if initialised with a list that includes a ValidationError instance initialised with a dict.

[Sean]

According to the documentation, ValidationError can be initialised with a list of ValidationError instances. However, if the list includes a ValidationError that was initialised with a dictionary then it crashes with the following error: 'ValidationError' object has no attribute 'error_list'.

This bug would occur if someone wanted to raise a ValidationError with a set of field errors together with one or more non-field errors for example.

For example:

>>> from django.core.exceptions import ValidationError
>>> ValidationError([ValidationError({'age', 'age cannot be negative'}), ValidationError('Some other error')])

The problem is caused because when a ValidationError instance is initialised with a dictionary, its error_list attribute is not set (instead error_dict is set) but a ValidationError that is initialised with a list tries to compile a flattened list of all errors using this attribute from each list element. Either ValidationError should be modified to accept a mixture of field and non-field errors (appears to me to be the best solution) or the documentation and error message should be changed to make usage clear.

Related to https://code.djangoproject.com/ticket/23976

[Andrey Maslov]

Created pull request: ​https://github.com/django/django/pull/3769

[Tim Graham <timograham@…>]

In 7a878ca5cb50ad65fc465cb263a44cc93629f75c:

Fixed #24008 -- Fixed ValidationError crash with list of dicts.

[Tim Graham <timograham@…>]

In 8de2a44064ca11749579a5887f59821fa35e1fdc:

[1.7.x] Fixed #24008 -- Fixed ValidationError crash with list of dicts.

Backport of 7a878ca5cb50ad65fc465cb263a44cc93629f75c from master