From 2e71df0156e7946959c91fac65a68cbcba341e95 Mon Sep 17 00:00:00 2001
From: Matthew Woehlke <matthew.woehlke@kitware.com>
Date: Mon, 1 Dec 2025 13:07:01 -0500
Subject: [PATCH] export: Explicitly allow empty NAMESPACE

Modify argument handling in `HandleExportMode` to explicitly allow an
empty `NAMESPACE`. In practice, this was already the case because we
weren't actually checking for the parsing errors that would cause the
`NonEmpty` decoration to reject an empty value, but we want to be able
to do that going forward, and changing the behavior for `NAMESPACE`
would potentially break legitimate uses. (In particular, one of our unit
tests relies on the current behavior.)
---
 Source/cmExportCommand.cxx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Source/cmExportCommand.cxx b/Source/cmExportCommand.cxx
index b4f73435af..736694209d 100644
--- a/Source/cmExportCommand.cxx
+++ b/Source/cmExportCommand.cxx
@@ -212,7 +212,7 @@ static bool HandleExportMode(std::vector<std::string> const& args,
   struct ExportArguments
   {
     ArgumentParser::NonEmpty<std::string> ExportSetName;
-    ArgumentParser::NonEmpty<std::string> Namespace;
+    ArgumentParser::MaybeEmpty<std::string> Namespace;
     ArgumentParser::NonEmpty<std::string> Filename;
     ArgumentParser::NonEmpty<std::string> CxxModulesDirectory;
     cm::optional<cmPackageInfoArguments> PackageInfo;