Same with CSV. It looks easy, but it isn't. I've never seen anyone who writes their own CSV parser actually implement features necessary to conform to the standard like quoting and escape sequences. The end result is software that breaks when delimiters or quotes appear in user input. Honestly, I prefer xlsx spreadsheets because of that. Nobody fools themselves into implementing the parser or serializer for the format themselves. The only tiny pitfall with them is when people create spreadsheets manually in excel and write numbers as text, but parsing strings to numbers is absolutely trivial. You have to do that with CSV anyway.

It really is easy:

$csv = str_getcsv( $input );

But PHP makes everything easy :trollface:

> I think a thing is not a good example though — takes longer than a few hours / an afternoon, to write a thing, add tests, fix bugs, corner cases. More like a week, or weeks, ...

You're making my point for me. This is exactly what I meant by the lifetime of support you're signing up for by writing lines of code. Once you write that code, you're now in the business of supporting that code. Was that a good decision for your business?

There's a fair middle ground when the dependency in itself doesn't have dependencies, and is small enough with a permissive license such that the entirety of its code can be dropped in to your project. Especially for very specific functionalities. I have used such tiny xml parsers, and I'm not affected by the fact that my copy is no longer the latest version. Its not so far from copying and pasting snippets of existing code.