From 5adea1a81d477df3ee16b52d718c98e7b1af1d65 Mon Sep 17 00:00:00 2001
From: taekop <taekop@naver.com>
Date: Mon, 5 Oct 2026 16:36:16 +0900
Subject: [PATCH] Don't fail in the shiny progress handler before the bar is
 shown (#762)

---
 DESCRIPTION                             |  1 +
 NEWS.md                                 |  3 +++
 R/progress-server.R                     | 10 ++++++----
 tests/testthat/test-progress-handlers.R | 15 +++++++++++++++
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index b42fa86a2..10feb225e 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -40,6 +40,7 @@ Suggests:
     rmarkdown,
     rprojroot,
     rstudioapi,
+    shiny,
     testthat (>= 3.2.0),
     tibble,
     whoami,
diff --git a/NEWS.md b/NEWS.md
index 170ac4d2c..d9ee07309 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -51,6 +51,9 @@
   error when the progress bar is drawn with a value below zero or above
   the total (#580, @taekop).
 
+* `cli_progress_output()` no longer fails with the Shiny progress handler
+  if the progress bar has not been shown yet (#762, @taekop).
+
 # cli 3.6.6
 
 * New `{.num}` and `{.bytes}` inline styles to format numbers
diff --git a/R/progress-server.R b/R/progress-server.R
index b2b287bdb..7846305ce 100644
--- a/R/progress-server.R
+++ b/R/progress-server.R
@@ -392,10 +392,12 @@ builtin_handler_shiny <- list(
   output = function(bar, .envir, text) {
     bar$shiny_output <-
       last_lines(paste0(bar$shiny_output, " \u2022 ", text))
-    bar$shiny_progress$set(
-      value = bar$current,
-      detail = shiny_detail(bar, .envir)
-    )
+    if (!is.null(bar$shiny_progress)) {
+      bar$shiny_progress$set(
+        value = bar$current,
+        detail = shiny_detail(bar, .envir)
+      )
+    }
   }
 )
 
diff --git a/tests/testthat/test-progress-handlers.R b/tests/testthat/test-progress-handlers.R
index 1f0944947..81cd1e4be 100644
--- a/tests/testthat/test-progress-handlers.R
+++ b/tests/testthat/test-progress-handlers.R
@@ -56,3 +56,18 @@ test_that("builtin_handlers", {
   expect_true(is.list(builtin_handlers()))
   expect_true(all(c("cli", "shiny", "rstudio") %in% names(builtin_handlers())))
 })
+
+test_that("shiny handler, cli_progress_output() before the bar is shown", {
+  skip_if_not_installed("shiny")
+  withr::local_options(
+    cli.progress_handlers_only = "shiny",
+    cli.progress_show_after = 3600
+  )
+  server <- function(input, output, session) {
+    id <- cli_progress_bar(total = 10)
+    cli_progress_output("custom message", id = id)
+    cli_progress_update(id = id)
+    cli_progress_done(id = id)
+  }
+  expect_no_error(shiny::testServer(server, {}))
+})