prompt becomes a question mark if Authors@R is NULL

[mcol]

I am experiencing a problem when running devtools::document() with roxygen2 version 6.0.1 (version 5.0.1 seems unaffected).

My package is not using the Authors@R construct. When processing the package documentation file (with the "_PACKAGE" sentinel), eventually package_authors() is reached, which calls parse(text = desc$Authors@R). My desc contains the following fields:

> names(desc)
 [1] "Package"     "Type"        "Title"       "Version"     "Date"       
 [6] "Author"      "Maintainer"  "Description" "License"     "URL"        
[11] "LazyLoad"    "Depends"     "Imports"     "LinkingTo"   "ByteCompile"
[16] "RoxygenNote"

So desc$Authors@R is NULL, hence parse() displays a ? as prompt, which cannot be dismissed without an error.