From b150e8757c17a060ae442266a2e61d8cb2d21252 Mon Sep 17 00:00:00 2001
From: Ralf Habacker <ralf.habacker@freenet.de>
Date: Tue, 3 Nov 2026 11:48:20 +0100
Subject: [PATCH] ctest: Restore handling of -U and --union with no value

Refactoring in commit c0c4d48ba2 (cmCTest: Use cmCommandLineArgument
command-line parsing infrastructure, 2024-10-12, v4.0.0-rc1~646^2)
accidentally made `-U` and `--union` require an argument, but the
documentation states that no argument is required.

Closes: #28243
---
 Source/cmCTest.cxx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Source/cmCTest.cxx b/Source/cmCTest.cxx
index ed1516f9a1..b1d8de5e9c 100644
--- a/Source/cmCTest.cxx
+++ b/Source/cmCTest.cxx
@@ -2445,8 +2445,8 @@ int cmCTest::Run(std::vector<std::string> const& args)
     CommandArgument{ "-I", CommandArgument::Values::One, dashI },
     CommandArgument{ "--tests-information", CommandArgument::Values::One,
                      dashI },
-    CommandArgument{ "-U", CommandArgument::Values::One, dashU },
-    CommandArgument{ "--union", CommandArgument::Values::One, dashU },
+    CommandArgument{ "-U", CommandArgument::Values::Zero, dashU },
+    CommandArgument{ "--union", CommandArgument::Values::Zero, dashU },
     CommandArgument{ "-R", CommandArgument::Values::One, dashR },
     CommandArgument{ "--tests-regex", CommandArgument::Values::One, dashR },
     CommandArgument{ "-E", CommandArgument::Values::One, dashE },