The information below is quoted for archival purposes, showing why $XVG Verge chose to steal $XSH SHIELD's code to fix their second devastating timewarp attack.
Let's start at the beginning.
When Verge initially got rekt by the timewarp attack, @sunerok makes the following commit (and also shows us he cant do basic maths?):
(2 * 15 = 30 seconds, not fifteen minutes...!? Anyway...)
He seems to realise there's something wrong with his maths (or maybe not, I'm not sure), but then he increases it to this (7.5mins):
Note that at this point, he has changed the timedrift value AFTER an attack on the chain. This makes wallets that update to this patch STUCK and unable to sync past the attacker's blocks, as also pointed out by @ocminer here:
So this attempt at an initial "fix" basically split the network in half! So to fix this, it's time for an emergency patch, right? :
So he reverts nMaxClockDrift back to its original value.
Then they try some messy new stuff inside the AcceptBlock() method for a fork at block 2040000, and also make oldMaxDrift:
@sunerok also tries to shrink Verge's drift time again (though I don't know why). This is also around the time SHIELD lead developer @NullFunction writes a proper timedrift patch and commits it to the SHIELD git:
@sunerok realises that by shrinking the drift size, despite the previous commit, the network is still split. So he reverts it:
All this proves a massive headache for #Vergefam when they get timewarp attacked yet again, so @sunerok looks through the code to find out what went wrong. Then he realises 'oh damn, I couldnt figure out how to fix that wretched timedrift thing, no wonder we got rekt again...'
'Wait, maybe SHIELD fixed it? I should probably go "check" their code'
Enter the copypasta (note how it is IDENTICAL to the patch shown above by @NullFunction, but made 50 days later):
So, can you work out who patched the drift first? Was it Verge, or was it actually SHIELD?
Here's Verge lead developer @sunerok in the Verge Telegram after the first timewarp attack, and before the second:
While @sunerok was sitting around calling himself a beast (for a patch that didn't work), guys on the SHIELD team not only saw the mistake, but predicted the actual attack method almost 50 days before it happened.