From 591872ea30c2e072999e33bca10f86d9cb56ec66 Mon Sep 17 00:00:00 2001
From: Patricia Aas <patricia@turtlesec.no>
Date: Tue, 22 Jun 2021 10:40:17 +0200
Subject: [PATCH] Try to make cmake to git submodule things

---
 CMakeLists.txt | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5518997..9b8dd96 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,6 +8,25 @@ project(modern_cpp_exercises )
 
 set(CMAKE_CXX_STANDARD 20)
 
+find_package(Git QUIET)
+if(GIT_FOUND AND EXISTS "${PROJECT_SOURCE_DIR}/.git")
+    # Update submodules as needed
+    option(GIT_SUBMODULE "Check submodules during build" ON)
+    if(GIT_SUBMODULE)
+        message(STATUS "Submodule update")
+        execute_process(COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive
+                WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+                RESULT_VARIABLE GIT_SUBMOD_RESULT)
+        if(NOT GIT_SUBMOD_RESULT EQUAL "0")
+            message(FATAL_ERROR "git submodule update --init failed with ${GIT_SUBMOD_RESULT}, please checkout submodules")
+        endif()
+    endif()
+endif()
+
+if(NOT EXISTS "${PROJECT_SOURCE_DIR}/vcpkg/LICENSE.txt")
+    message(FATAL_ERROR "The submodules were not downloaded! GIT_SUBMODULE was turned off or failed. Please update submodules and try again.")
+endif()
+
 add_subdirectory(lib)
 add_subdirectory(src)
 add_subdirectory(test)