Fix save_image() compatibility with kaleido v1 (#2475)

cpsievert · claude · cpsievert · commit b1103b226742 · 2026-01-23T11:12:49.000-06:00
Use py_has_attr() instead of tryNULL() to check for kaleido.scopes
attribute. Accessing a non-existent Python attribute can throw an
AttributeError that may not be caught properly by tryCatch in certain
reticulate configurations.

Also add force(kaleido) in newKaleidoScope to avoid potential lazy
evaluation issues with closures.

Co-Authored-By: Claude Opus 4.5 &lt;noreply@anthropic.com&gt;
diff --git a/R/kaleido.R b/R/kaleido.R
@@ -97,17 +97,18 @@ kaleido <- function(...) {
     }
   )
   
-  res <- if (is.null(tryNULL(kaleido$scopes))) {
-    newKaleidoScope(kaleido)
-  } else {
+  res <- if (reticulate::py_has_attr(kaleido, "scopes")) {
     legacyKaleidoScope(kaleido)
+  } else {
+    newKaleidoScope(kaleido)
   }
   
   class(res) <- "kaleidoScope"
   res
 }
 
 newKaleidoScope <- function(kaleido) {
+  force(kaleido)
   list(
     scopes = NULL,
     transform = function(p, file, ..., width = NULL, height = NULL, scale = NULL) {

Original file line number	Diff line number	Diff line change
`@@ -97,17 +97,18 @@ kaleido <- function(...) {`
`97`	`97`	`}`
`98`	`98`	`)`
`99`	`99`
`100`		`- res <- if (is.null(tryNULL(kaleido$scopes))) {`
`101`		`- newKaleidoScope(kaleido)`
`102`		`- } else {`
	`100`	`+ res <- if (reticulate::py_has_attr(kaleido, "scopes")) {`
`103`	`101`	`legacyKaleidoScope(kaleido)`
	`102`	`+ } else {`
	`103`	`+ newKaleidoScope(kaleido)`
`104`	`104`	`}`
`105`	`105`
`106`	`106`	`class(res) <- "kaleidoScope"`
`107`	`107`	`res`
`108`	`108`	`}`
`109`	`109`
`110`	`110`	`newKaleidoScope <- function(kaleido) {`
	`111`	`+ force(kaleido)`
`111`	`112`	`list(`
`112`	`113`	`scopes = NULL,`
`113`	`114`	`transform = function(p, file, ..., width = NULL, height = NULL, scale = NULL) {`