Fix vignette build on Windows: forward-slash bib path

R/bibliography.R

@@ -66,9 +66,12 @@ create_biblio_file <- function(packages, out.dir,
     x = bib_lines[grep("PACKAGES_HERE", bib_lines)])
 
   # path to bib
+  # Use forward slashes: on Windows, tempdir() returns "C:\Users\...",
+  # and a substring like "\U..." is parsed as an invalid Unicode escape
+  # when the chunk is re-evaluated in the Rmd.
   bib_lines[grep("BIBPATH_HERE", bib_lines)] <- gsub(
     pattern = "BIBPATH_HERE",
-    replacement = paste0('"', dir_temp, '"'),
+    replacement = paste0('"', gsub("\\\\", "/", dir_temp), '"'),
     x = bib_lines[grep("BIBPATH_HERE", bib_lines)])
 
   # Link citation

tests/testthat/test-bibliography.R

@@ -0,0 +1,40 @@
+test_that("create_biblio_file substitutes BIBPATH with forward slashes", {
+  # On Windows, tempdir() returns a path with backslashes (e.g. "C:\Users\...").
+  # If that path is interpolated as-is into the rendered Rmd, R parses
+  # substrings like "\U..." as Unicode escapes and the chunk fails with
+  # `Error in file(): cannot open the connection`. The substitution must
+  # use forward slashes so the path is a valid R string literal on every OS.
+
+  fake_dir <- "C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\RtmpXXXX"
+  bib_template <- c(
+    "knitr::write_bib(packages, file.path(BIBPATH_HERE, 'packages.bib'))"
+  )
+  substituted <- gsub(
+    pattern = "BIBPATH_HERE",
+    replacement = paste0('"', gsub("\\\\", "/", fake_dir), '"'),
+    x = bib_template
+  )
+
+  expect_false(grepl("\\\\", substituted))
+  expect_true(grepl("C:/Users/RUNNER~1/AppData/Local/Temp/RtmpXXXX", substituted, fixed = TRUE))
+
+  expect_silent(
+    parse(text = substituted)
+  )
+})
+
+test_that("create_biblio_file produces an html bibliography", {
+  out <- tempfile()
+  dir.create(out)
+
+  suppressMessages(
+    create_biblio_file(
+      packages = c("rmarkdown", "knitr"),
+      out.dir = out,
+      to = "html",
+      edit = FALSE
+    )
+  )
+
+  expect_true(file.exists(file.path(out, "bibliography.html")))
+})