Which is correct here, have or has?

Question

Which is correct here, have or has?

The original sentence.

In addition to halting the chain, an organizer will also rollback through the object that it has performed so that the failed object and each completed object has the opportunity to undo itself.

There was a suggestion to use "have" instead of "has" here.

In addition to halting the chain, an organizer will also rollback through the object that it has performed so that the failed object and each completed object have the opportunity to undo itself.

I'm not convinced that this is correct. My argument is that failed object, each completed object, and itself all reference singular nouns. I also think I have to change the tense of the sentence (e.g., will have).

If have is correct here, I'd like to know why. And at a minimum, having itself sounds wrong.

Can anyone offer the correct form and an explanation?

Answer 1

The subject of the clause is "the failed object and each completed object"; since it is plural, the verb needs to be have.

My father and I are going to visit my grandfather.

My girlfriend and her sister have visited Italy at least once.

That is because the clause is using and as conjunction; if it uses or, the subject would be singular.

My cousin or my sister knows the person who broken the glass of my car. They were near my car at the time it happened, but neither of them wants to say what happened.

I would rephrase the sentence as follows:

In addition to halting the chain, an organizer also rollbacks the actions done on the handled objects, so that the failed objects and each completed object have the opportunity to undo [direct object] themselves.

The present tense is perfectly fine in that case, since you are describing something that happens.

Pressing that button activates a camera, which captures an image of your face, and compares it with the images of people working for the company owning the building. If you are one of them, the door opens, and you can enter.

Itself/themselves sounds strange in that sentence because the direct object of undo is the action being undone.

He undid most of the good work of the previous manager.

It's not too late to try and undo some of the damage.

You could also say "the jacket undid itself," but in this case the phrase means (for example) that one or more buttons of the jacket unfastened without nobody touching the buttons.