From 0cc24534d7ad8174e759a24abf8e0cde716db886 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Wed, 18 Feb 2026 19:47:23 -0500
Subject: [PATCH] ctest --launch: Restore sharing of stdin with child process

This was broken by commit 96b3dd329e (cmCTestLaunchReporter: Replace
cmsysProcess with cmUVProcessChain, 2023-07-26, v3.28.0-rc1~138^2~2).
KWSys Process shares stdin by default.  Now it must be explicit.

Issue: #27610
---
 Source/CTest/cmCTestLaunch.cxx | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Source/CTest/cmCTestLaunch.cxx b/Source/CTest/cmCTestLaunch.cxx
index 9669d76a32..cbe53a7705 100644
--- a/Source/CTest/cmCTestLaunch.cxx
+++ b/Source/CTest/cmCTestLaunch.cxx
@@ -152,6 +152,9 @@ void cmCTestLaunch::RunChild()
   cmUVProcessChainBuilder builder;
   builder.AddCommand(this->RealArgV);
 
+  // We always share the input pipe.
+  builder.SetExternalStream(cmUVProcessChainBuilder::Stream_INPUT, stdin);
+
   cmsys::ofstream fout;
   cmsys::ofstream ferr;
   if (this->Reporter.Passthru) {