del StripeOject.metadata['some_key'] deletes key AND raises KeyError

[apinsard]

python: 3.5.3
stripe-python: 2.29.4

I just experienced quite unexpected KeyError exception the following code:

# pi is a `stripe.PaymentIntent`
if 'damage_deposit_amount' in pi.metadata:
    del pi.metadata['damage_deposit_amount']  # <- raises `KeyError`

According to the information I have in my error report 'damage_deposit_amount' is indeed not in pi.metadata. So, I first thought 'key' in StripeObject always returns True.

However, after testing it in a python console I figured out the following:

In [1]: from utils.stripe import stripe  # (= import stripe + stripe.api_key = settings.STRIPE['SECRET_KEY'])

In [2]: pi = stripe.PaymentIntent.retrieve('pi_deadbeef')

In [3]: pi.metadata
Out[3]: 
<StripeObject at 0x7f92140c5098> JSON: {
  "booking_id": "13506",
  "damage_deposit_amount": "20000",
  "waiting_for_webhook": "True"
}

In [4]: 'foobar' in pi.metadata
Out[4]: False

In [5]: del pi.metadata['damage_deposit_amount']
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-5-e399e0ff7d29> in <module>
----> 1 del pi.metadata['damage_deposit_amount']

/usr/share/virtualenvs/cocoonr/lib/python3.5/site-packages/stripe/stripe_object.py in __delitem__(self, k)
    136         # Allows for unpickling in Python 3.x
    137         if hasattr(self, "_unsaved_values"):
--> 138             self._unsaved_values.remove(k)
    139
    140     # Custom unpickling method that uses `update` to update the dictionary

KeyError: 'damage_deposit_amount'

In [6]: pi.metadata
Out[6]: 
<StripeObject at 0x7f92140c5098> JSON: {
  "booking_id": "13506",
  "waiting_for_webhook": "True"
}

In [7]: pi.save()
Out[7]: 
<PaymentIntent payment_intent id=pi_deadbeef at 0x7f9214136598> JSON: {
  ...
  "metadata": {
    "booking_id": "13506",
    "waiting_for_webhook": "True"
  },
  ...
}

In [8]: pi = stripe.PaymentIntent.retrieve('pi_deadbeef')

In [9]: pi.metadata
Out[9]: 
<StripeObject at 0x7f92168b07c8> JSON: {
  "booking_id": "13506",
  "damage_deposit_amount": "20000",
  "waiting_for_webhook": "True"
}

In [10]:

To sum it up:

1. del pi.metadata['damage_deposit_amount'] deleted the key, but raised a KeyError.
2. Saving the object returned an object without the deleted key.
3. Reloading the object showed that the key was actually not deleted.

[ob-stripe]

Hi @apinsard, thanks for the report.

You can unset metadata keys like this:

stripe.PaymentIntent.modify('pi_deadbeef', metadata={'damage_deposit_amount': ''})

or like this:

pi = stripe.PaymentIntent.retrieve('pi_deadbeef')
pi.metadata['damage_deposit_amount'] = None
pi.save()

Nevertheless, the KeyError when using the del keyword is unexpected. We'll investigate and work on a fix (or at least a clearer error message).

[apinsard]

Thank you for the quick answer and the provided workaround!

[ob-stripe]

I just released version 2.33.1, using del should no longer throw a KeyError. Though note that to unset metadata keys you'd still need to use one of the two ways I showed in my previous message.