vectorise textVersion of bib entries

[bastistician]

tweaking a949228 and #1267 to account for CITATION files with multiple bib entries, where pkgdown currently always uses the textVersion even if that is missing

[bastistician]

See the current colorspace site at http://colorspace.r-forge.r-project.org/authors.html (generated with pkgdown 1.6.1) for an example of missing HTML versions of the citations:

I expect many other packages with multiple citations to be affected by this bug as the textVersion element is often not needed and then "recommended to leave unspecified", see help(bibentry).

[hadley]

Could you provide a test or two too please?

[bastistician]

Could you provide a test or two too please?

Yes, see my additional commit.
Note that all CITATION tests are excluded from R CMD check.

BTW, I think the "textVersion" format should be HTML-escaped in case it contains & < or > (e.g., "Proof of b < a"):

diff --git a/R/build-home-citation.R b/R/build-home-citation.R
index fe19872..a69b757 100644
--- a/R/build-home-citation.R
+++ b/R/build-home-citation.R
@@ -48,7 +48,7 @@ data_citations <- function(pkg = ".") {
   cit <- list(
     html = ifelse(text_version == "",
                   format(cit, style = "html"),
-                  paste0("<p>", text_version, "</p>")),
+                  paste0("<p>", escape_html(text_version), "</p>")),
     bibtex = format(cit, style = "bibtex")
   )

Let me know if I should add this change as a commit to this PR.

[hadley]

Yes, would be great to fix the HTML escaping while you're in here (with another test please). Thanks for the help!

[hadley]

Does R already take care of escaping { in bibtex? i.e. what if the title is Proof of b < a { c?