roxygen2 8.1.0

• Markdown support:
  • Multibyte characters inside Rd tags are now handled correctly; previously a tag like \code{café} would corrupt the markdown processing of the text that followed it.
  • Warnings triggered by an rd_family_title prefix (e.g. for an unsupported level 1 heading) no longer error.
  • Link targets and inherited Rd topics are now resolved with cached indexes provided by the new rdtools package, replacing repeated help() calls and roxygen2's own topic lookup and package-qualification code. This substantially speeds up documenting packages with many cross-references, e.g. Rd generation for testthat is nearly twice as fast.
• DESCRIPTION:
  • The migration from RoxygenNote to Config/roxygen2/version now happens whenever it's needed, not just when the roxygen2 version has changed. This fixes two cases where the deprecated RoxygenNote field was left in DESCRIPTION forever: when a collaborator using roxygen2 7.x re-added it after the package had already been migrated, and when its value happened to match the installed version (#1876).
  • Config/roxygen2/ flag fields (like markdown) are now parsed case-insensitively, so true and True work as well as TRUE, and an invalid value gives a clear error (#1875).
  • The automatic usage for a data object now recognises all the ways of setting LazyData to true, e.g. yes, Yes, and True (@jranke, #1881).
• NAMESPACE:
  • @import now inserts the directive as is when it contains a comma, making it possible to use other forms like @import rlang, except = ":=".
  • @importFrom now generates a single multi-line importFrom() directive per package instead of one directive per symbol. This fixes a performance issue with loadNamespace() for packages that import many symbols.
  • @importFrom, @importClassesFrom, and @importMethodsFrom now accept multi-line input, restoring the ability to spread imports across multiple lines for readability. Continuation lines must use a hanging indent, so the tag ends at the first unindented or blank line, and content after it (e.g. from a forgotten @examples) is no longer silently absorbed into the namespace (#1890).
• @inheritParams no longer errors when a topic uses argument selection in more than one tag, e.g. @inheritParams a x followed by @inheritParams b y (#1879). If the same source is used in multiple tags, the union of their selections is now inherited, rather than the selections being ignored, so an unfiltered tag inherits every parameter.
• @section titles can now contain code that includes a colon (#1878).
• S7 methods for [, [[, [<-, and [[<- now generate valid usage (#1883).
• setAs() and setGroupGeneric() are now recognised, so they get the same automatic alias and \usage as setMethod() and setGeneric(), fixing the "Rd files without \usage" note from R CMD check (#1908).