From f53d60a9efa5ff224bd0adcc9ac39685fd79b1a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Cs=C3=A1rdi?= <csardi.gabor@gmail.com>
Date: Thu, 9 Oct 2025 20:45:33 +0200
Subject: [PATCH] Fix potential error when worker process crashes

Reading the output might fail, so we need to `tryCatch()` it.

Closes #2262.
---
 R/parallel-taskq.R | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/R/parallel-taskq.R b/R/parallel-taskq.R
index 22300ce8b..2f0d0e776 100644
--- a/R/parallel-taskq.R
+++ b/R/parallel-taskq.R
@@ -88,8 +88,14 @@ task_q <- R6::R6Class(
             pr[[i]][["error"]] == "ready"
           outmsg <- NULL
           if (has_output) {
-            lns <- c(worker$read_output_lines(), worker$read_error_lines())
-            inc <- paste0(worker$read_output(), worker$read_error())
+            lns <- c(
+              safely(worker$read_output_lines(), character()),
+              safely(worker$read_error_lines(), character())
+            )
+            inc <- paste0(
+              safely(worker$read_output(), ""),
+              safely(worker$read_error(), "")
+            )
             if (nchar(inc)) {
               lns <- c(lns, strsplit(inc, "\n", fixed = TRUE)[[1]])
             }
@@ -249,4 +255,11 @@ df_add_row <- function(df, ..., .before = NULL) {
   }
 }
 
+safely <- function(expr, default = NULL) {
+  tryCatch(
+    expr,
+    error = function(e) default
+  )
+}
+
 silence_r_cmd_check <- function() callr::r_session