use base::isFALSE() instead

yihui/xfun#67

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: blogdown
 Title: Create Blogs and Websites with R Markdown
-Version: 1.15.3
+Version: 1.15.4
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Christophe", "Dervieux", role = "aut", email = "[email protected]", comment = c(ORCID = "0000-0003-4474-2498")),
@@ -43,6 +43,7 @@ License: GPL-3
 URL: https://github.com/rstudio/blogdown,
     https://pkgs.rstudio.com/blogdown/
 BugReports: https://github.com/rstudio/blogdown/issues
+Depends: R (>= 3.5.0)
 Imports:
     bookdown (>= 0.22),
     htmltools,

NEWS.md

@@ -4,6 +4,8 @@
 
 - Fixed a bug that caused `config.toml.bak.toml` to be recognized as the config file mistakenly, which led to an obscure error (thanks, @CerebralMastication, #742).
 
+- This package requires R >= 3.5.0 now.
+
 # CHANGES IN blogdown VERSION 1.15
 
 - Restored the old default `options(blogdown.method = "html")` (thanks, @pachadotdev, #739).

R/render.R

@@ -68,7 +68,7 @@ build_site = function(local = FALSE, run_hugo = TRUE, build_rmd = FALSE, ...) {
   if (!knitting) on.exit(run_script('R/build.R', as.character(local)), add = TRUE)
   if (build_method() == 'custom') return()
 
-  if (!xfun::isFALSE(build_rmd)) {
+  if (!isFALSE(build_rmd)) {
     if (is.character(build_rmd) && length(build_rmd) == 1) {
       build_rmd = switch(
         build_rmd, timestamp = filter_timestamp, md5sum = filter_md5sum,