You don't approve it. You just slowly grind the submitter down with minor feedback. At some point they lose interest and after a year you can close the PR, or ask the submitter to open a new PR.
It works best if you don't reply immediately. I recommend successively increasing the response delay. Keep it short enough to make sure that they don't start bugging you on other channels, but long enough to make sure they have time to cool down and question if the continued effort is really worth it.
As long as the response delay increases at least geometrically, there is a finite bound to the amount of work required to deal with a pull request that you will never merge.
Tragically, when you are organisationally impaired from saying 'no', this is the only way (besides, you know, quitting and getting a new job).
It's absolutely soul crushing when you're motivated to do a good job, but have a few colleagues around you that have differing priorities, and aren't empowered to do the right thing, even when management agrees with you.
I am both an open source maintainer and contributor. This is absolutely despicable behavior. You are purposefully wasting the time of a contributor for no other reason than your own fear of saying “no.”
If you’re not going to merge something, just ficking say so.
If you've read the thread, the strategy you're replying to is about a workplace scenario where outright rejection is, for whatever reason, forbidden; not an open source situation where "no" is readily available.
It makes even less sense in a work context either. This behavior will permanently alienate this user & potential customer. I’ve seen this exact scenario play out many times before.
Why would it be acceptable for the sumbitter to behave this way and not the reviewer? We do have AI "assisted" submitters behaving exactly like this and acting irate when forced to actually reflect on the turd they're trying to shove into my inbox