Allow template packages to provide a default configuration `_pkgdown.…

…yml` (#1565)

Co-authored-by: Hadley Wickham <h.wickham@gmail.com>

NEWS.md

@@ -1,5 +1,13 @@
 # pkgdown (development version)
 
+* Allow template packages to provide a default configuration `_pkgdown.yml`, 
+  stored in `inst/pkgdown/_pkgdown.yml`. This can be used to set (e.g.) author 
+  definitions, Bootstrap version and variables, the sidebar, footer, navbar, etc.
+
+  Configuration parameters supplied by a template package have the lowest priority
+  They will be overridden by a local `_pkgdown.yml` which is in turn overridden by
+  `override` parameter of `build_site()`. (#1499)
+
 * pkgdown now contains templates using Bootstrap 4 (with help from @jayhesselberth).
    * Easy customisation of colours and fonts with bslib
    * Thoughtful typography to make the contents as easy as possible to read, regardless of the size of your device.

R/init.R

@@ -72,18 +72,20 @@ copy_assets <- function(pkg = ".") {
 
   # Copy assets from package
   if (!is.null(template$package)) {
-    copy_asset_dir(
-      pkg,
-      path_package_pkgdown(
-        template$package,
-        bs_version = pkg$bs_version,
-        "assets"
-      )
+    assets <- path_package_pkgdown(
+      template$package,
+      bs_version = get_bs_version(pkg),
+      "assets"
     )
+
+    copy_asset_dir(pkg, assets)
   }
 }
 
 copy_asset_dir <- function(pkg, from_dir, file_regexp = NULL) {
+  if (length(from_dir) == 0) {
+    return(character())
+  }
   from_path <- path_abs(from_dir, pkg$src_path)
   if (!file_exists(from_path)) {
     return(character())

R/package.r

@@ -20,6 +20,9 @@ as_pkgdown <- function(pkg = ".", override = list()) {
   meta <- read_meta(pkg)
   meta <- utils::modifyList(meta, override)
 
+  template_config <- find_template_config(meta[["template"]]$package)
+  meta <- modify_list(template_config, meta)
+
   # Ensure the URL has no trailing slash
   if (!is.null(meta$url)) {
     meta$url <- sub("/$", "", meta$url)
@@ -213,3 +216,16 @@ package_vignettes <- function(path = ".") {
     description = desc
   )
 }
+
+find_template_config <- function(package) {
+  if (is.null(package)) {
+    return(list())
+  }
+
+  config <- path_package_pkgdown(package, bs_version = NULL, "_pkgdown.yml")
+  if (length(config) == 0) {
+    return(list())
+  }
+
+  yaml::yaml.load_file(config) %||% list()
+}

R/utils-fs.R

@@ -106,10 +106,7 @@ path_package_pkgdown <- function(package, bs_version = NULL, ...) {
       return(path_package_pkgdown(package, bs_version = NULL, ...))
     }
 
-    stop(
-      package, " does not contain ", src_path("inst/pkgdown/", ...),
-      call. = FALSE
-    )
+    return(character())
   }
 
   pkg_path

R/utils.r

@@ -190,5 +190,6 @@ modify_list <- function(x, y) {
   if (is.null(y)) {
     return(x)
   }
+
   utils::modifyList(x, y)
 }