From 9f83d275e8ca508785554488f78c460cc07adc4e Mon Sep 17 00:00:00 2001
From: prjanitor <prjanitortool@gmail.com>
Date: Thu, 2 Apr 2026 08:55:24 +0300
Subject: [PATCH] Fix missing error handling for IPC::Open3 in ipc_open3
 subroutine

Add validation to check if open3() succeeds before attempting to read from filehandles. If open3() fails, $writer, $reader, and $error will be undefined, causing silent failures or crashes when reading from undefined filehandles.

Closes #431
---
 lib/MIP/System_call.pm | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/MIP/System_call.pm b/lib/MIP/System_call.pm
index 8d8af3601..1ed9e0803 100644
--- a/lib/MIP/System_call.pm
+++ b/lib/MIP/System_call.pm
@@ -108,6 +108,11 @@ sub ipc_open3 {
     # System call
     my $pid = open3( $writer, $reader, $error, qq{$command_string} );
 
+    # Check if open3 succeeded
+    unless (defined $pid) {
+        croak(qq{open3 failed for command "$command_string": $OS_ERROR});
+    }
+
     # Terminate process
     waitpid $pid, 0 or croak(qq{Child process died: $OS_ERROR});