GH-47005: [C++] Disable exporting CMake packages (#47006)

kou · web-flow · commit f52d81bca789 · 2025-07-13T07:16:22.000+09:00
### Rationale for this change azure-sdk-for-cpp uses `export(PACKAGE)` https://cmake.org/cmake/help/latest/command/export.html#package . It changes user package registry (`~/.cmake/packages/`) https://cmake.org/cmake/help/latest/manual/cmake-packages.7.html#user-package-registry . It's outside of a build directory. If user package registry is changed, other build may be failed. ### What changes are included in this PR? Disable `export(PACKAGE)`. ### Are these changes tested? Yes. ### Are there any user-facing changes? Yes. * GitHub Issue: #47005 Authored-by: Sutou Kouhei <kou@clear-code.com> Signed-off-by: Sutou Kouhei <kou@clear-code.com>
diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
@@ -61,6 +61,11 @@ cmake_policy(SET CMP0074 NEW)
 # option() honors normal variables.
 cmake_policy(SET CMP0077 NEW)
 
+# https://cmake.org/cmake/help/latest/policy/CMP0090.html
+#
+# export(PACKAGE) does nothing by default.
+cmake_policy(SET CMP0090 NEW)
+
 # https://cmake.org/cmake/help/latest/policy/CMP0091.html
 #
 # MSVC runtime library flags are selected by an abstraction.
diff --git a/cpp/cmake_modules/ThirdpartyToolchain.cmake b/cpp/cmake_modules/ThirdpartyToolchain.cmake
@@ -1016,7 +1016,8 @@ macro(prepare_fetchcontent)
   set(BUILD_TESTING OFF)
   set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "")
   set(CMAKE_COMPILE_WARNING_AS_ERROR OFF)
-  set(CMAKE_EXPORT_NO_PACKAGE_REGISTRY OFF)
+  set(CMAKE_EXPORT_NO_PACKAGE_REGISTRY ON)
+  set(CMAKE_EXPORT_PACKAGE_REGISTRY OFF)
   set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "")
   set(CMAKE_MACOSX_RPATH ${ARROW_INSTALL_NAME_RPATH})
   # We set CMAKE_POLICY_VERSION_MINIMUM temporarily due to failures with CMake 4
