That claim doesn't even work for the 0 line shell script that used to be /bin/true (which is why it is no longer a 0 line shell script), much less any more complicated program.
Fuck those people, people who says that usually doesn't even understand half the time. When I ask people like that when they write a functionality a certain way during code review usually they'll just quote someone on Twitter or some blogspam article saying A is shit, B is the best way to do things.
you forget StackOverflow. I saw my coworker once copy-and-paste code... from the question.... and not understand why it wasn't working.... I'm all for using StackOverflow to get help with weird problems but, most of the time, simply reading the docs and applying that knowledge to the problem you are trying to solve is enough. a forgotten art for sure.....
I'd pretend to be Joey from Hackers and just throw commands at it to see what happens. Maybe I'll make an ATM in bumfuck, Egypt spit out hundreds of dollars or find a worm in a garbage file 🤷🏻♂️
Only if the source is structured and has readable names. Spaghetti code with made up variable names that only the programmer knows the meaning of (or may not even remember what they mean at all) isn't that much better than combing through the disassembled machine code.
Which is fine for a.small and simple tool. But I have seen massive graphic/UI libraries with a documentation of about two pages and a non-working example.
Worst offenders I have to deal with is mediawiki. Some random hacker replaces some code with his own, and immeditely obsoletes the previous code that worked absolutely fine. The new code might work, too, but the concept, the philosophy is 100% different that the old interface. So e.g. the old interface made a call with 10 or 20 parameters, the new one makes a ton of calls of the type "add one or two parameters to an object".
And of course the only documentation is just the excrement of a Doxygen call. Where nobody ever cared for the function description headers in the source.
My "favourite" one is a function with a parameter named "options" and a description as "option flags". Nothing more. And the source of the function? Well, I have seen staighter spaghetti dinners.