The point of the numbering changes is if you want to insert a new item half way through the list you don't have to change every single line. Unfortunately it probably confuses people more often than it helps them.
I've had very similar experiences as you. Every automatic "correction" of user input needs to at least be clearly indicated and easily reversible. In my opinion it shouldn't even happen until the user actively signed off on the proposed modification.
I think the same argument can be made for almost every "the machine knows better than the user" decision, so it seems to me that this is pointing out that the Markdown list behaviour should be tarred with exactly the same brush.
This is true of all these features in general. They're all well-intentioned. No one wants to design a system that annoys users. But my criteria is meant to illustrate why it might not have been a smart idea to begin with: the user didn't indicate they wanted the system to renumber their bullet points. In fact, very often the user indicates that they want a specific numbering by placing specific numbers. The feature would work if there was some way to indicate this is just a bulleted list with numbers. Instead, the system assumes 100% of the time that the user made an error, then fixes that error in a way that is difficult to detect without ever providing feedback about the changes. That's a bad system that happens to usually be trivial or at most embarrassing. But the design itself is flawed from first principles.
A better way to implement auto-numbered lists would be indicate you want to use auto-numbered lists, just like you indicate you want to use headings, links, or any other element. First, don't rewrite all numbers, making the fact that a correction is taking place under the hood invisible to even experienced users. Auto-numbered lists should be indicated by having multiple lines starting with, say, "<space>0.", or even better "<space>#." to be more congruent with the use of "#" for headings and subheadings in other markdown systems (languages?). Second, when a user submits a post, the system should indicate what has been changed, perhaps with a non-intrusive highlight.
The problem would never have arisen had the developers asked my two questions "did the user indicate X?" and "where/how did the user indicate X?"
I suppose you should add onto that "is the change transparent to the user?" which is also known to cause some potentially life-threatening errors: http://www.dkriesel.com/en/blog/2013/0802_xerox-workcentres_... - you probably think "it's markdown, what's the big deal?", but who knows. Maybe someone gets some medical or chemistry advice and, sure, they shouldn't trust reddit, but then maybe someone dies anyway. So I think it's always best practice to indicate that a change has been made.
1. If you insert a misnumbered item in the middle of the list then when you come back later to edit the text you will be confused by how the numbers in the source are different from the numbers in the formatted output.
2. There's no point in using a numbered list unless you're going to refer to the number(s) somehow. (In this case I'm using the word "couple" to introduce the list!) Markdown doesn't sort out those references for you so in practice you have to manually renumber things anyway.
I propose a new term: paternalistic software. It's software that overdoes being helpful, and becomes annoying or dangerous. It's the software that does things you don't want automatically, because it thinks it knows better than you. Automatic renumbering and autocorrect both fall under this.
It looks like you're trying to write a rant against Clippy. Would you like help?
maybe the solution is to renumber if a list uses all 1's, but leave it untouched if it has different out of order numbers.
So this gets renumbered:
1. item 1
1. item 2
1. item 3
But this does not:
1.
3.
7.
Reddit could then offer "use our text-editor assistant in your browser" to those who aren't using one.
The text box would have to define what it allowed as input: alnum, plaintext, markdown, etc., and the appropriate plugin would activate?
Like #463 GitHub auto linking, which I usually like, but occasionally been caught by it.
But I wouldn't—and it's a lot easier for you to process your Markdown and paste it into an HTML-enabled text field than it is for me to process my HTML and paste it into a text field that understands only one of the flavours of Markdown that doesn't have sufficient escape hatches built in (or that, like most flavours, has lots of features built in that you're apparently supposed to discover only by experimentation, preferably without any sandbox or preview available).