Bookdown text references not working if URL contains special characters

问题

There is some inconsistent behaviour of text references in bookdown with URLs containing special characters such as : or _. Here are some demonstrations:

---
output: bookdown::pdf_book
---

(ref:good) [This Works](https://commons.wikimedia.org/wiki)

(ref:good)


(ref:bad) [This Does Not](https://commons.wikimedia.org/wiki/File:Linear_visible_spectrum.svg)

(ref:bad)


The link will work normally [like here](https://commons.wikimedia.org/wiki/File:Linear_visible_spectrum.svg)

Is there a way to get text references to work if they contain special characters?

---

This behaviour was flagged in this question here, but the symbols were not directly identified as the key issues within the question. I wanted to make a focussed thread on SO before raising it as a potential issue on GitHub.

回答1:

The problem was not caused by special characters but the fact that the link was too long, so the line in LaTeX was wrapped by Pandoc by default:

(ref:bad)
\href{https://commons.wikimedia.org/wiki/File:Linear_visible_spectrum.svg}{This Does Not}

It should be considered as a bug of bookdown, but there is a workaround:

output:
  bookdown::pdf_book:
    pandoc_args: [--wrap=none]

来源：https://stackoverflow.com/questions/50098235/bookdown-text-references-not-working-if-url-contains-special-characters