Is dropping the final period in a bare url done by-design?

Question

I have no idea if this is a potentially exploitable security issue or just a nit pick. In this comment:

yep! ;-) btw that's A._B._and_C. If you just past the link without the brackets, the SE url parser (for lack of a better name) thinks you made a mistake and truncates the link before the final period: https://en.wikipedia.org/wiki/A._B._and_C.

I point out that a bare url (from Wikipedia) that ends in a period is truncated, and sends you to the url without the period.

This automatic behavior produces a bad link when a good (but bare) link is pasted.

Is there any way to avoid this? I don't think it rises to the level of a bug, but is the auto-dropping of the trailing period in the url done by-design?

Answer 1

To answer the question in the title: yes. When URLs are auto-linked trailing periods, commas, question marks, etc. are discarded. This is status-bydesign for obvious reasons (i.e. ending of sentences often contain an URL) as explained by balpha in Why isn't the period rendered after a question link?.

The way to avoid it is to use the Markdown formatting for URLs as explained in How do I make this URL ending in a period work in the comments?. That is, use [https://en.wikipedia.org/wiki/A._B._and_C.](https://en.wikipedia.org/wiki/A._B._and_C.) or [<short-description>](https://en.wikipedia.org/wiki/A._B._and_C.).