support svglite dependency inference (#1930)

NEWS.md

@@ -1,6 +1,9 @@
 
 # renv (development version)
 
+* `renv` now infers a dependency on the `svglite` package if it detects
+  calls of the form `ggsave(filename = "path.svg")`. (#1930)
+
 * `renv` now supports setting of GitHub authentication credentials via
   any of `GITHUB_TOKEN`, `GITHUB_PAT`, and `GH_TOKEN`. (#1937)
 

R/dependencies.R

@@ -1060,6 +1060,7 @@ renv_dependencies_discover_r <- function(path = NULL,
     renv_dependencies_discover_r_box,
     renv_dependencies_discover_r_targets,
     renv_dependencies_discover_r_glue,
+    renv_dependencies_discover_r_ggplot2,
     renv_dependencies_discover_r_parsnip,
     renv_dependencies_discover_r_database
   )
@@ -1423,6 +1424,30 @@ renv_dependencies_discover_r_glue <- function(node, stack, envir) {
 
 }
 
+renv_dependencies_discover_r_ggplot2 <- function(node, stack, envir) {
+
+  node <- renv_call_expect(node, "ggplot2", "ggsave")
+  if (is.null(node))
+    return(FALSE)
+
+  # check for attempts to save to '.svg', and assume svglite is
+  # required in this scenario.
+  matched <- catch(match.call(function(filename, ...) {}, node))
+  if (inherits(matched, "error"))
+    return(FALSE)
+
+  filename <- matched$filename
+  if (!is.character(filename))
+    return(FALSE)
+
+  if (!endswith(filename, ".svg"))
+    return(FALSE)
+
+  envir[["svglite"]] <- TRUE
+  TRUE
+
+}
+
 renv_dependencies_discover_r_glue_impl <- function(string, node, envir) {
 
   # get open, close delimiters

tests/testthat/test-dependencies.R

@@ -550,3 +550,18 @@ test_that("dependencies() with different extensions", {
   expect_true("B" %in% deps$Package)
 
 })
+
+test_that("dependencies() can infer an svglite dependency from ggsave", {
+
+  document <- heredoc('
+    library(ggplot2)
+    ggsave(filename = "test.svg")
+  ')
+
+  file <- renv_scope_tempfile("renv-test-", fileext = ".R")
+  writeLines(document, con = file)
+
+  deps <- dependencies(file, quiet = TRUE)
+  expect_contains(deps$Package, "svglite")
+
+})