Repairing photos stuck on 100%
MacBook Pro, iOS 10.3.3
You really need to make a backup of the library before you try to repair it. Otherwise you cannot restore it, when the repair fails or gets stuck like now.
As it is now, you can only wait a bit longer to see, if the repair will finally finish.
If it does not finish at all, shut down the Mac, the restart the Mac in Safe Mode as described here (Use safe mode to isolate issues with your Mac - Apple Support). This will clear some caches, the restart normally, make a backup copy of the library and try to repair again.
Sometimes a second repair will finish more quickly after a restart.
Details please? What version of the OS are you using? Where is your Photos library located? If on an external drive what is the drive format?
and your choice not to have a backup is a very bad choice and gives you a 100% guarantee that you will lose everything including your photos sooner or later - hopefully not but it may have just happened - if your data and photos have any value to you you must always have a good, current bacup
LN
Repairing photos stuck on 100%