As a counter to Chesterton's Fence: sometimes the fastest way to understand what something does is to remove it and see what complains. You might get only 1 complainer for every 10 fences you take down. Putting that one fence back up takes much longer than taking it down, but the time saved from removing the other 9 unnecessary ones makes it a net win. And this time you can add Documentation to the rebuilt fence.
A further counterpoint: if you follow the Fence proponents' logic to its conclusion you can never remove any code which is clearly an absurd situation.
I think the real logical flaw is that Fencers (as I will now call them) put the blame on the person who removes an apparently useless fence. But they're wrong. The real blame lies with the person who built the apparently useless fence and didn't put a sign on it explaining why it shouldn't be removed.
> A further counterpoint: if you follow the Fence proponents' logic to its conclusion you can never remove any code which is clearly an absurd situation.
No, that would only be the case if one would never understand any code. Chesterton's Fence consists of two parts ("understanding some code" as a precondition to "removing some code"), and leaving one or the other part out makes it some other thing than what Chesterton's Fence means.
> The real blame lies with the person who built the apparently useless fence and didn't put a sign on it explaining why it shouldn't be removed.
Chesterton's Fence is not about blame, or the past in general - it is about how to deal with things that are in the present. (Although I agree that the original fence-builder should have left a note or two!)
The principle says you can’t remove it until you understand why it was there. It’s more about doing due diligence.
I follow the principle when I remove code, and it’s a reason why good code comments are important. “Oh yeah, this was written for [x] which is no longer a thing, we can remove it now”
And not putting up a sign explaining why it's a necessary fence is a bad decision. Avoiding removing all unlabeled fences because they might, maybe, potentially be useful, is also likely a bad decision if taken to it's conclusion.
Chesterton's Fence is a reminder to actually get up, walk over to the fence and skim the multiple labels and notes the builders left there - because the big problem is usually someone looking at a thing that came before them, and assuming they understand what it was for, without bothering to actually check it.
