Can we get more info from the missing required fields validator?

Consider:

import jsonschema

schema = {
	"type": "object",
	"properties": {
		"cat": {
			"type": "string"
		},
		"dog": {
			"type": "string"
		}
	},
	"required": ["cat","dog"]
}

data = {
	"cat": "socks"
}

validator = jsonschema.Draft7Validator(schema)

for e in validator.iter_errors(data):
	print("ERROR")
	for k,v in e.__dict__.items():
		print(k + " = " + str(v))

The output is:

ERROR
message = 'dog' is a required property
path = deque([])
relative_path = deque([])
schema_path = deque(['required'])
relative_schema_path = deque(['required'])
context = []
cause = None
validator = required
validator_value = ['cat', 'dog']
instance = {'cat': 'socks'}
schema = {'type': 'object', 'properties': {'cat': {'type': 'string'}, 'dog': {'type': 'string'}}, 'required': ['cat', 'dog']}
parent = None
_type_checker = <TypeChecker types={'array', 'boolean', 'integer', 'null', 'number', 'object', 'string'}>

In this case, only the "dog" field is missing but there is no field on the error that tells me that without taking apart the message (which I don't want to do as the message is more likely to change that a separate field).

validator_value lists both fields so that isn't useful.

Comparing the validator_value items to keys in instance may work, but that gets complex if there are 3 or more required fields:

import jsonschema

schema = {
	"type": "object",
	"properties": {
		"cat": {
			"type": "string"
		},
		"dog": {
			"type": "string"
		},
		"ferret": {
			"type": "string"
		}
	},
	"required": ["cat","dog", "ferret"]
}

data = {
	"cat": "socks"
}

validator = jsonschema.Draft7Validator(schema)

for e in validator.iter_errors(data):
	print("ERROR")
	for k,v in e.__dict__.items():
		print(k + " = " + str(v))

Gives:

ERROR
message = 'dog' is a required property
path = deque([])
relative_path = deque([])
schema_path = deque(['required'])
relative_schema_path = deque(['required'])
context = []
cause = None
validator = required
validator_value = ['cat', 'dog', 'ferret']
instance = {'cat': 'socks'}
schema = {'type': 'object', 'properties': {'cat': {'type': 'string'}, 'dog': {'type': 'string'}, 'ferret': {'type': 'string'}}, 'required': ['cat', 'dog', 'ferret']}
parent = None
_type_checker = <TypeChecker types={'array', 'boolean', 'integer', 'null', 'number', 'object', 'string'}>
ERROR
message = 'ferret' is a required property
path = deque([])
relative_path = deque([])
schema_path = deque(['required'])
relative_schema_path = deque(['required'])
context = []
cause = None
validator = required
validator_value = ['cat', 'dog', 'ferret']
instance = {'cat': 'socks'}
schema = {'type': 'object', 'properties': {'cat': {'type': 'string'}, 'dog': {'type': 'string'}, 'ferret': {'type': 'string'}}, 'required': ['cat', 'dog', 'ferret']}
parent = None
_type_checker = <TypeChecker types={'array', 'boolean', 'integer', 'null', 'number', 'object', 'string'}>

Could we have a new field added to this error to just state what is missing? (in the first example - "dog")

Happy to have a go if you think this is a good idea.

Thank you!

[Julian]

Hi, this is #119 -- which essentially is going to be solved by doing #119 (comment) -- a small PR to get that started likely is indeed welcome, though it's also on my own TODO list after I finish working on the $ref implementation.

Certainly if you care to give it a shot though it's welcome in small chunks! Otherwise keep an eye on that issue.