> The only validation I'd always enforce is some sane length limit, [..]

Venture into the abyss of UTF-8 and behold the madness of multibyte characters. Diacritics dance devilishly upon characters, deceiving your simple count. Think a letter is but a single entity? Fools! Combining characters lurk in the shadows, binding invisibly, elongating the uninitiated's count into chaos. Every attempt to enumerate the true length of a string in UTF-8 conjures a specter of complications. Behold, a single glyph, yet multiple bytes cackle beneath, a multitude of codepoints coalesce in arcane unison. It is beautiful t he final snuffing of the lie s of Man ALL IS LOST ALL I S LOST the pony he comes he comes he comes the ich or permeates all MY FACE MY FACE ᵒh god no NO NOOO O NΘ stop the an * gles are n ot real ZALGΌ IS TOƝȳ THE PO NY HE COMES