VueJS extend component: remove parent's property

I have two Vue components, one extends the other:

// CompA.vue

export default {
    props: {
        value1: Object,
    },

    data: function () {
        return {
            value2: 'hello2 from A',
            value3: 'hello3 from A'
        }
    }
}

// CompB.vue

import CompA from './CompA.vue';

export default {
    extends: CompA,

    props: {
        value4: Object
    },

    data: function(){
        return {
            value2: 'hello2 from B'
        }
    }
}

As described in the docs, CompB's options are merged into CompA's, resulting:

{
    props: {
        value1: Object,
        value4: Object
    },

    data: function () {
        return {
            value2: 'hello2 from B',
            value3: 'hello3 from A'
        }
    }
}

However my desired result is having property value1 removed:

{
    props: {
        value4: Object
    },

    data: function () {
        return {
            value2: 'hello2 from B',
            value3: 'hello3 from A'
        }
    }
}

I think it should be possible using Custom Option Merge Strategies

But even if I return null or undefined, the property isn't removed.

Vue.config.optionMergeStrategies.data = function(parentVal, childVal) {
    return null;
};

Is it even possible to such thing? If yes, how?