Error validating with nested oneOf/anyOf/allOf

[mikethecalamity]

What version of Ajv are you using? Does the issue happen if you use the latest version?
7.2.3 (latest)

Ajv options object

const Ajv = require("ajv/dist/2019").default;
const ajvFormats = require('ajv-formats').default;
const ajv = new Ajv({
    allErrors: true,
    validateFormats: true
});
ajvFormats(ajv);

JSON Schema

{
    "$schema": "https://json-schema.org/draft/2019-09/schema",
    "$id": "https://test.com/test.json",
    "type": "object",
    "anyOf": [
        {
            "required": [ "flag" ],
            "properties": {
                "type": {
                    "const": "FOO"
                },
                "flag": {
                    "type": "boolean"
                }
            }
        },
        {
            "properties": {
                "type": {
                    "enum": [ "BAR", "BAZ" ]
                }
            },
            "anyOf": [
                {
                    "required": [ "name" ],
                    "properties": {
                        "name": {
                            "type": "string"
                        }
                    }
                },
                {
                    "required": [ "value" ],
                    "properties": {
                        "value": {
                            "type": "number"
                        }
                    }
                }
            ]
        }
    ]
}

Sample data

{
    "type": "BAR",
    "value": 500
}

Your code

https://runkit.com/mweber03/605d4480645b6e001a445577

var validate = ajv.compile(schema);
console.log(validate(data));

Validation result, data AFTER validation, error messages

TypeError: Cannot convert undefined or null to object
    at Function.assign ()
    at validate539 (eval at compileSchema (node_modules\ajv\dist\c ompile\index.js:88:30), :3:4381)

What results did you expect?
A successful validation (It worked with draft04 and v5.2.0)

Are you going to resolve the issue?

[epoberezkin]

Confirmed - it is caused by handling of evaluated properties (to support unevaluatedProperties).

https://runkit.com/esp/605d8a27a850060013d0af69

If you do not use unevaluatedProperties keyword (or any other new draft-2019-09 features), you should use default import - it would have a smaller generated code.

Another workaround is to use ajv.opts.unevaluated = false (it would not work if you use unevaluatedProperties/Items keywords).

[epoberezkin]

in 7.2.4