only move _files/_cache dirs that have corresponding Rmd files

this should fix the problem reported at #1307 (comment), in which case config_files was moved by mistake

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: bookdown
 Type: Package
 Title: Authoring Books and Technical Documents with R Markdown
-Version: 0.36.1
+Version: 0.36.2
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Christophe", "Dervieux", , "[email protected]", role = c("ctb"),

NEWS.md

@@ -2,6 +2,8 @@
 
 - Custom config files passed to the `config_file` argument of `render_book()` are no longer temporarily renamed to `_bookdown.yml` (thanks, @debruine, #1307).
 
+- Do not move all `_files` directories temporarily to the `_bookdown_files` directory when calling `render_book()` (thanks, @steeleb, #1307).
+
 # CHANGES IN bookdown VERSION 0.36
 
 - Fix an issue with parsing resources from raw HTML code (thanks, @lennylin, https://community.rstudio.com/t/bookdown-image-with-a-weblink/172542)

R/utils.R

@@ -448,8 +448,11 @@ base64_css = function(css, exts = 'png', overwrite = FALSE) {
 
 files_cache_dirs = function(dir = '.') {
   if (!dir_exists(dir)) return(character())
-  out = list.files(dir, '_(files|cache)$', full.names = TRUE)
+  r = '_(files|cache)$'
+  out = list.files(dir, r, full.names = TRUE)
   out = out[dir_exists(out)]
+  # only use dirs that have corresponding Rmd files
+  if (dir == '.') out = out[file.exists(sub(r, '.Rmd', out))]
   out = out[basename(out) != '_bookdown_files']
   out
 }