Problem/Motivation
When editing a Workflow which has been created with either no states or no transitions (or both)) an Invalid argument error will be displayed.
No states: Warning: Invalid argument supplied for foreach() in Drupal\workflows\Form\WorkflowEditForm->copyFormValuesToEntity() (line 276 of core/modules/workflows/src/Form/WorkflowEditForm.php).
No transitions: Warning: Invalid argument supplied for foreach() in Drupal\workflows\Form\WorkflowEditForm->copyFormValuesToEntity() (line 279 of core/modules/workflows/src/Form/WorkflowEditForm.php).
This will only occur in rare cases where the Workflow Plugin does no provide any required states and when creating the Workflow the user chooses not to create the initial state when prompted. In this scenario it appears that in some cases $form_state->getValues() may not contain the states or transitions keys, which results in the errors being shown.
Tested using the
Workflows Field →
contrib module, which provides a plugin with no required states.
Currently this does not appear to be reliably reproducible, no other information is currently available which would indicate why this is not reliably reproducible.
Proposed resolution
Remaining tasks
Determine if code should be refactored to prevent the errors from being triggered, or wait until this can be more reliably reproduced.
User interface changes
API changes
Data model changes