>In my pull request, I had noted that a given test suite and the associated code weren’t actually used and working and so I was commenting them out. At the time, he told me to delete the lines instead of commenting them out; citing that “dead code” (e.g., unused, unexercised or otherwise unneeded code) served as a greater liability than source of future implementation and re-use.
I generally agree with this sentiment ... but while a likely good rule-of-thumb, you also have to know when it's NOT good to apply
If you have version control, it's almost always correct - delete away, and revert if you need to
But when you don't ... commenting-out (and dating when it was commented) ends up serving as a [very] poor man's version control
I end up having to do this (or make copies and only work on the copy) with the product I use most for work because it has NO concept of version control anywhere ... and the add-ons that attempt it do it very poorly