fix: don't register full_screen Shiny input for non-full-screen cards

NEWS.md

@@ -2,6 +2,8 @@
 
 ## Bug fixes
 
+* `card()` and `value_box()` no longer register `input$<id>_full_screen` for cards that don't have `full_screen = TRUE`, avoiding unexpected inputs in bookmarking workflows. (#1305)
+
 * Fixed label-to-options spacing on `shiny::radioButtons()` and `shiny::checkboxGroupInput()` in Bootstrap 5, where a Shiny rule was overriding the bslib fix. (#1308)
 
 # bslib 0.11.0

R/card.R

@@ -26,10 +26,9 @@
 #'   together into one `wrapper` call (e.g. given `card("a", "b",
 #'   card_body("c"), "d")`, `wrapper` would be called twice, once with `"a"` and
 #'   `"b"` and once with `"d"`).
-#' @param id Provide a unique identifier for the `card()` or `value_box()` to
-#'   report its full screen state to Shiny. For example, using `id = "my_card"`,
-#'   you can observe the card's full screen state with
-#'   `input$my_card_full_screen`.
+#' @param id A unique identifier for the card. Note that full-screen
+#'   capability cannot be added after card creation; `full_screen` must be set
+#'   at creation time.
 #'
 #' @return A [htmltools::div()] tag.
 #'
@@ -90,7 +89,11 @@ card <- function(
   children <- as_card_items(args[!nzchar(argnames)], wrapper = wrapper)
   children <- card_image_add_classes(children)
 
-  is_shiny_input <- !is.null(id)
+  # When full_screen=TRUE and id is provided, the card registers
+  # input$<id>_full_screen to report its full screen state to Shiny.
+  # The bslib-card-input class is what triggers this JS-side registration,
+  # so it must only be added when the card actually has full screen capability.
+  is_shiny_input <- !is.null(id) && full_screen
 
   if (full_screen && is.null(id)) {
     # a11y: full screen cards need an ID for aria-controls on the toggle button

tests/testthat/test-card.R

@@ -40,6 +40,20 @@ test_that("card_image()", {
   )
 })
 
+test_that("card() only registers as Shiny input when full_screen=TRUE", {
+  card_no_fs <- card(id = "my_card", "content")
+  card_with_fs <- card(id = "my_card", full_screen = TRUE, "content")
+  card_fs_no_id <- card(full_screen = TRUE, "content")
+
+  classes_no_fs <- htmltools::tagGetAttribute(card_no_fs, "class")
+  classes_with_fs <- htmltools::tagGetAttribute(card_with_fs, "class")
+  classes_fs_no_id <- htmltools::tagGetAttribute(card_fs_no_id, "class")
+
+  expect_no_match(classes_no_fs, "bslib-card-input")
+  expect_match(classes_with_fs, "bslib-card-input")
+  expect_no_match(classes_fs_no_id, "bslib-card-input")
+})
+
 test_that("card_image() input validation", {
   expect_snapshot(
     error = TRUE,