From 53982dbab4fd3eb01b0712b2eacbdb38ea15d850 Mon Sep 17 00:00:00 2001
From: Joey Parrish <joeyparrish@users.noreply.github.com>
Date: Mon, 17 Jul 2023 06:41:23 -0700
Subject: [PATCH] chore: Split out CMake policies into package/policies.cmake
 (#1236)

---
 CMakeLists.txt          | 23 ++++-------------------
 packager/policies.cmake | 31 +++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 19 deletions(-)
 create mode 100644 packager/policies.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 55a815d0c8..412f911b93 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,35 +6,20 @@
 
 # Root-level CMake build file.
 
-# Minimum CMake version.
+# Minimum CMake version.  This must be in the root level CMakeLists.txt.
 # We could require as low as 3.10, but glog requires 3.16.
 cmake_minimum_required(VERSION 3.16)
 
+# These policy settings should be included before the project definition.
+include("packager/policies.cmake")
+
 # Project name.  May not contain spaces.  Versioning is managed elsewhere.
-cmake_policy(SET CMP0048 NEW)
 project(shaka-packager VERSION "")
 
 # The only build option for Shaka Packager is whether to build a shared
 # libpackager library.  By default, don't.
 option(LIBPACKAGER_SHARED "Build libpackager as a shared library" OFF)
 
-# No in-source builds allowed.
-set(CMAKE_DISABLE_SOURCE_CHANGES ON)
-set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
-# TODO: Prevent accidental cmake invocation from deeper inside packager tree?
-
-# Minimum C++ version.
-set(CMAKE_CXX_STANDARD 17)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-
-# Minimum GCC version, if using GCC.
-if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
-  # Require at least GCC 9.  Before GCC 9, C++17 filesystem libs don't link.
-  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9)
-    message(FATAL_ERROR "GCC version must be at least 9! (Found ${CMAKE_CXX_COMPILER_VERSION})")
-  endif()
-endif()
-
 # Global include paths.
 # Project root, to reference packager/foo/bar/...
 include_directories(.)
diff --git a/packager/policies.cmake b/packager/policies.cmake
new file mode 100644
index 0000000000..c6ba4451b3
--- /dev/null
+++ b/packager/policies.cmake
@@ -0,0 +1,31 @@
+# Copyright 2023 Google LLC. All rights reserved.
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+# CMake policy settings.  These will be included before the project definition.
+# NOTE: Flags like MSVC are not available at this level.
+
+# Do not set default warning levels for MSVC.  We will choose the warning level.
+cmake_policy(SET CMP0092 NEW)
+
+# Use modern project versioning behavior to avoid a warning on newer CMake.
+cmake_policy(SET CMP0048 NEW)
+
+# No in-source builds allowed.
+set(CMAKE_DISABLE_SOURCE_CHANGES ON)
+set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
+# TODO: Prevent accidental cmake invocation from deeper inside packager tree?
+
+# Minimum C++ version.
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# Minimum GCC version, if using GCC.
+if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+  # Require at least GCC 9.  Before GCC 9, C++17 filesystem libs don't link.
+  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9)
+    message(FATAL_ERROR "GCC version must be at least 9! (Found ${CMAKE_CXX_COMPILER_VERSION})")
+  endif()
+endif()