Non Boolean comparisons in flow.switch().case() Django-Viewflow

Question

I have a standar viewflow flow process, in one of the states id want to split my proccess based on the text value that is introduced in one of the fields. I have defined my field of interest this way in models.py

estado_de_aprobacion= models.CharField(max_length=15, choices=REVIEW_CHOICES)

my choices:

REVIEW_CHOICES = (
   ('APROBACION_FINAL', 'Aprobar definitivamente'),
   ('APROBACION_NUEVO_REVISOR', 'Enviar a otro revisor'),
   ('DEVOLVER_EJECUTOR','Devolver al ejecutor')
)

so basically what happens is that a drop list is displayed so the user can choose one of the options, and based on that I appliy the followinf split in the flow:

split =(
        #If(lambda activation: activation.process.aprobacion_final)
        flow.Switch()
        .Case(this.end, cond=((lambda act: act.process.estado_de_aprobacion)=='APROBACION_FINAL'))
        .Case(this.revisor_check, cond=((lambda act: act.process.estado_de_aprobacion)=='APROBACION_NUEVO_REVISOR'))
        .Case(this.ejecutar, cond=((lambda act: act.process.estado_de_aprobacion)=='DEVOLVER_EJECUTOR'))
    )

I assume that the lamba expression returns the value contained in the specified proccess atributes but since the comparisson isn't working im thinking its wrong.

score 1 · Accepted Answer · answered Feb 21 '19 at 16:51

Let's unpack what is going on in the cond value.

cond=((lambda act: act.process.estado_de_aprobacion)=='APROBACION_FINAL')

(lambda act: act.process.estado_de_aprobacion) returns a function which extracts the relevant field from act. Then you are comparing this to =='APROBACION_FINAL', which is always going to fail because you are comparing a lambda function and a string. So the actual value of cond being passed to the function is False.

I assume cond need to be a function that returns true or false? In which case you should do the comparison in the lambda function.

cond=lambda act: act.process.estado_de_aprobacion=='APROBACION_FINAL'

The extract parentheses in the original code are unnecessary, and are in fact probably the source of the problem.

Non Boolean comparisons in flow.switch().case() Django-Viewflow

1 Answers1