From b8d24365f69863e2afd8ba6ee1486a0257550403 Mon Sep 17 00:00:00 2001
From: Thomas Jarosch <thomas.jarosch@intra2net.com>
Date: Wed, 31 Dec 2025 11:36:59 +0100
Subject: [PATCH] Modernize Boost module finding for CMake 3.30+

Add CMP0167 policy to suppress FindBoost deprecation warning on CMake 3.30+

Use modern Boost imported targets (Boost::iostreams, Boost::thread,
Boost::unit_test_framework) when available (CMAKE_VERSION >= 3.30)

Fallback to old-style variables for CMake 3.28.

Split target_link_libraries calls: Boost libraries + non-Boost libraries.

"include_directories" for Boost handled in root CMakeLists.txt.

Fixes: CMake warning about deprecated FindBoost module on CMake 3.30+:
*******************************************
CMake Warning (dev) at CMakeLists.txt:137 (find_package):
  Policy CMP0167 is not set: The FindBoost module is removed.  Run "cmake
  --help-policy CMP0167" for policy details.  Use the cmake_policy command to
  set the policy and suppress this warning.
*******************************************
---
 CMakeLists.txt      |   15 +++++++++++++--
 src/CMakeLists.txt  |   13 +++++++------
 test/CMakeLists.txt |   13 +++++++------
 3 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 308f85e..07f53fe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,12 @@
 cmake_minimum_required(VERSION 3.28 FATAL_ERROR)
 
+# Modern Boost integration (CMake 3.30+)
+# Use CMake's built-in Boost support instead of deprecated FindBoost module
+# For CMake < 3.30, keep old behavior to avoid errors
+if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.30)
+    cmake_policy(SET CMP0167 NEW)
+endif()
+
 # Project
 project(libi2ncommon)
 
@@ -134,8 +141,12 @@ endif(IMAP_UTF7_SUPPORT)
 include(FindPkgConfig)
 
 # Find Boost
-find_package(Boost 1.44 COMPONENTS iostreams unit_test_framework thread REQUIRED)
-include_directories(${Boost_INCLUDE_DIRS})
+find_package(Boost 1.44 REQUIRED COMPONENTS iostreams unit_test_framework thread)
+
+# CMake 3.28 compatibility: imported targets only available in CMake 3.30+
+if(CMAKE_VERSION VERSION_LESS 3.30)
+    include_directories(${Boost_INCLUDE_DIRS})
+endif()
 
 # Find pcrecpp
 pkg_check_modules(PCRECPP REQUIRED libpcrecpp)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 881dd88..43fa40a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -62,12 +62,13 @@ SET(cpp_headers
 
 add_library(i2ncommon SHARED ${cpp_sources} ${cpp_headers})
 
-target_link_libraries(i2ncommon
-                      ${Boost_IOSTREAMS_LIBRARIES}
-                      ${Boost_THREAD_LIBRARIES}
-                      ${ICONV_LIBRARIES}
-                      ${OPENSSL_LIBRARIES}
-                      ${PCRECPP_LIBRARIES})
+# CMake 3.30+ provides modern imported targets, CMake 3.28 uses old-style variables
+if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.30)
+    target_link_libraries(i2ncommon Boost::iostreams Boost::thread)
+else()
+    target_link_libraries(i2ncommon ${Boost_IOSTREAMS_LIBRARIES} ${Boost_THREAD_LIBRARIES})
+endif()
+target_link_libraries(i2ncommon ${ICONV_LIBRARIES} ${OPENSSL_LIBRARIES} ${PCRECPP_LIBRARIES})
 
 set_target_properties(i2ncommon PROPERTIES VERSION ${VERSION} SOVERSION 8)
 set_target_properties(i2ncommon PROPERTIES OUTPUT_NAME i2ncommon CLEAN_DIRECT_OUTPUT 1)
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 6694bff..673a4e3 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -36,9 +36,10 @@ add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} DEPENDS test_i2ncommon)
 enable_testing()
 add_test(test_i2ncommon test_i2ncommon)
 
-target_link_libraries(test_i2ncommon
-    i2ncommon
-    i2ncommon_utils
-    i2ncommon_config
-    ${Boost_UNIT_TEST_FRAMEWORK_LIBRARIES}
-)
+# CMake 3.30+ provides modern imported targets, CMake 3.28 uses old-style variables
+if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.30)
+    target_link_libraries(test_i2ncommon Boost::unit_test_framework)
+else()
+    target_link_libraries(test_i2ncommon ${Boost_UNIT_TEST_FRAMEWORK_LIBRARIES})
+endif()
+target_link_libraries(test_i2ncommon i2ncommon i2ncommon_utils i2ncommon_config)
-- 
1.7.1