From c21226ed94a91742449f49482e31747e3aab781f Mon Sep 17 00:00:00 2001
From: tz <185176969+tzhaoo@users.noreply.github.com>
Date: Wed, 7 Oct 2026 15:58:52 +0200
Subject: [PATCH] Reuse parent-provided ZLIB::ZLIB target

When ScopeWriter is added as a subdirectory of a project that already
defines ZLIB::ZLIB (for example via a static Qt build that pulls in
WrapZLIB), creating the alias fails with a duplicate target error.
Only alias the bundled zlibstatic when no ZLIB::ZLIB target exists.
---
 CMakeLists.txt | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 181a887..d40dc8c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,7 +19,10 @@ add_subdirectory(
         EXCLUDE_FROM_ALL
 )
 unset(SKIP_INSTALL_ALL)
-add_library(ZLIB::ZLIB ALIAS zlibstatic)
+# A parent project may already provide ZLIB::ZLIB (e.g. via a static Qt build).
+if (NOT TARGET ZLIB::ZLIB)
+    add_library(ZLIB::ZLIB ALIAS zlibstatic)
+endif ()
 
 set(CRC32C_BUILD_TESTS OFF)
 set(CRC32C_BUILD_BENCHMARKS OFF)