support upper-case engine names (closes #1803)

NEWS.md

@@ -1,5 +1,9 @@
 # renv (development version)
 
+* Fixed an issue where `renv` could fail to infer dependencies from
+  R Markdown code chunks using engine 'R' (upper-case) rathern than
+  'r' (lower-case). (#1803)
+
 * Fixed an issue where `renv` did not report out-of-sync packages when
   one or more packages used in the project were not installed. (#1788)
 

R/dependencies.R

@@ -814,7 +814,7 @@ renv_dependencies_discover_chunks_ignore <- function(chunk) {
 
   # skip non-R chunks
   engine <- chunk$params[["engine"]]
-  ok <- is.character(engine) && engine %in% c("r", "rscript")
+  ok <- is.character(engine) && tolower(engine) %in% c("r", "rscript")
   if (!ok)
     return(TRUE)
 
@@ -905,7 +905,7 @@ renv_dependencies_discover_chunks <- function(path, mode) {
   if (mode %in% "qmd") {
     for (chunk in chunks) {
       engine <- chunk$params[["engine"]]
-      if (is.character(engine) && engine %in% c("r", "rscript")) {
+      if (is.character(engine) && tolower(engine) %in% c("r", "rscript")) {
         qdeps <- renv_dependencies_list(path, "rmarkdown")
         break
       }

tests/testthat/test-dependencies.R

@@ -500,3 +500,18 @@ test_that("dependencies() can parse NAMESPACE files", {
   expect_setequal(deps$Package, c("graphics", "tools", "utils"))
 
 })
+
+test_that("dependencies() handles upper-case engine names", {
+
+  document <- heredoc("
+    ```{R}
+    library(A)
+    ```
+  ")
+
+  file <- renv_scope_tempfile(fileext = ".Rmd")
+  writeLines(document, con = file)
+  deps <- dependencies(file, quiet = TRUE)
+  expect_true("A" %in% deps$Package)
+
+})