Update method ignoring partial flag on serializer (updates all fields)

[mlaxm]

Update method ignoring partial flag on serializer (updates all fields)

[sarathak]

@mlaxm I believe there might be a misunderstanding regarding the partial function. The partial function specifically avoids validating certain fields. If you provide data without a required field, regular validation will trigger an error. However, when using partial, it won't enforce validation for those specific fields.

for example :

data = {
    "bio": "new bio",
}
serializer = UserSerializer(user, data=data, partial=False)
serializer.is_valid(raise_exception=True)

this will through validation error

with partial it will not through error

data = {
    "bio": "new bio",
}
serializer = UserSerializer(user, data=data, partial=True)
serializer.is_valid(raise_exception=True)

[mlaxm]

Thank you, @sarathak, for providing clarification on the functionality of the "partial" argument. I appreciate the insight into its purpose.

I would like to draw further attention to the matter raised in my previous comment regarding the save operation. Given that I am performing a partial update and consequently not encountering any validation errors from the serializer (as I am only intending to update the "bio" field, for instance), it seems that all fields of the user instance are being updated. I am seeking clarification on whether this behavior aligns with the intended workflow? It may not be the expected outcome when employing partial updates

[AlexanderNeilson]

@mlaxm

Partial updates documentation is fairly explicit that partial allows partial updates. It does not change the other behaviours.

You have shown in your example one way to selectively update only some fields.

Are you establishing a "patch" method that will execute the partial update with fields? This may be a semantic side effect of development if you are creating your API to perform partial updates on put method queries instead of using patch for the partial update.

If you want to use other http verbs to perform a partial update you can do so but your code will need to identify the fields being updated and only update those fields.

The save method doesn't know that you only want it to operate on the limited fields unless you tell it. You have opened up an object, built a serializer based on the object you grabbed and the submitted data, then you saved it. So it then saves the entire serializer object.

Regards
Alexander

[mlaxm]

@AlexanderNeilson
According to the source code, either the .create or .update methods are called (with .update being invoked if the instance exists). This update method in turn calls the .save method on the serializer. My concern is that the .save method on the serializer always updates all of the model's fields, rather than just a few. There doesn't appear to be a way to specify updating only validated fields?
Thanks for your assistance