feat: Use stable leaflet.providers html dep if available (#884)

Author: gadenbuie

DESCRIPTION

@@ -54,7 +54,7 @@ Imports:
     htmltools,
     htmlwidgets (>= 1.5.4),
     jquerylib,
-    leaflet.providers (>= 1.8.0),
+    leaflet.providers (>= 1.13.0.9001),
     magrittr,
     methods,
     png,
@@ -79,4 +79,6 @@ Suggests:
 Config/testthat/edition: 3
 Encoding: UTF-8
 LazyData: true
+Remotes:
+    rstudio/leaflet.providers
 RoxygenNote: 7.2.3

NEWS.md

@@ -1,5 +1,7 @@
 # leaflet (development version)
 
+* When `addProviderTiles()` is used with `{leaflet.providers}` version 2.0.0 or later, the `leaflet-providers` HTML dependency produced can be correctly cached by knitr. When used with older versions of `{leaflet.providers}`, the HTML dependency uses temp files that break knitr's caching mechanism (thanks @qdread, @jaredlander; #884).
+
 # leaflet 2.2.0
 
 ### Features

R/plugin-providers.R

@@ -89,7 +89,19 @@ NULL
 # Active binding added in zzz.R
 "providers.src"
 
+# Active binding added in zzz.R
+"providers.dep"
+
 get_providers_html_dependency <- function() {
+  if (is.null(providers.dep)) {
+    return(create_temp_providers_html_dependency())
+  }
+
+  providers.dep
+}
+
+create_temp_providers_html_dependency <- function() {
+  # for compatibility with older versions of leaflet.providers
   tmpfile <- file.path(tempdir(), paste0("leaflet-providers_", providers.version_num, ".js"))
 
   if (!file.exists(tmpfile)) {

R/zzz.R

@@ -15,4 +15,8 @@ leaflet_envir <- environment()
   makeActiveBinding("providers.src", function() {
     leaflet.providers::providers_loaded()$src
   }, env = leaflet_envir)
+
+  makeActiveBinding("providers.dep", function() {
+    leaflet.providers::providers_loaded()$dep
+  }, env = leaflet_envir)
 }