From ede60451a91bec12e889338a13d2a336ae138648 Mon Sep 17 00:00:00 2001
From: Thomas Mosegaard Pedersen <thomas-mp@users.noreply.github.com>
Date: Tue, 26 Jul 2022 09:15:11 +0200
Subject: [PATCH] CPMAddPackage fails if the SOURCE_DIR directory is deleted.
 (#370)

* Fixed: Deleted SOURCE_DIR directory would abort just after git stash save --quiet;--include-untracked

* Fixed: Review comments

* Added: Integration test for deleted SOURCE_DIR with FetchContent

* Fixed: Review comments

* Fixed: Review comments
---
 cmake/CPM.cmake                            | 14 +++++++++
 test/integration/test_remove_source_dir.rb | 36 ++++++++++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 test/integration/test_remove_source_dir.rb

diff --git a/cmake/CPM.cmake b/cmake/CPM.cmake
index 9b47e70..6271991 100644
--- a/cmake/CPM.cmake
+++ b/cmake/CPM.cmake
@@ -650,6 +650,20 @@ function(CPMAddPackage)
     list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS DOWNLOAD_COMMAND ${CPM_ARGS_DOWNLOAD_COMMAND})
   elseif(DEFINED CPM_ARGS_SOURCE_DIR)
     list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS SOURCE_DIR ${CPM_ARGS_SOURCE_DIR})
+    if(NOT IS_ABSOLUTE ${CPM_ARGS_SOURCE_DIR})
+      # Expand `CPM_ARGS_SOURCE_DIR` relative path. This is important because EXISTS doesn't work
+      # for relative paths.
+      get_filename_component(
+        source_directory ${CPM_ARGS_SOURCE_DIR} REALPATH BASE_DIR ${CMAKE_CURRENT_BINARY_DIR}
+      )
+    else()
+      set(source_directory ${CPM_ARGS_SOURCE_DIR})
+    endif()
+    if(NOT EXISTS ${source_directory})
+      string(TOLOWER ${CPM_ARGS_NAME} lower_case_name)
+      # remove timestamps so CMake will re-download the dependency
+      file(REMOVE_RECURSE "${CPM_FETCHCONTENT_BASE_DIR}/${lower_case_name}-subbuild")
+    endif()
   elseif(CPM_SOURCE_CACHE AND NOT CPM_ARGS_NO_CACHE)
     string(TOLOWER ${CPM_ARGS_NAME} lower_case_name)
     set(origin_parameters ${CPM_ARGS_UNPARSED_ARGUMENTS})
diff --git a/test/integration/test_remove_source_dir.rb b/test/integration/test_remove_source_dir.rb
new file mode 100644
index 0000000..852c12d
--- /dev/null
+++ b/test/integration/test_remove_source_dir.rb
@@ -0,0 +1,36 @@
+require_relative './lib'
+
+class RemoveSourceDir < IntegrationTest
+  def test_remove_source_dir
+    prj = make_project 'using-adder'
+    
+    prj.create_lists_from_default_template package: <<~PACK
+      CPMAddPackage(
+        NAME testpack-adder
+        GITHUB_REPOSITORY cpm-cmake/testpack-adder
+        VERSION 1.0.0
+        OPTIONS "ADDER_BUILD_TESTS OFF"
+        SOURCE_DIR testpack-adder
+      )
+    PACK
+
+    # configure and build
+    assert_success prj.configure
+    assert_success prj.build
+
+    # source_dir is populated
+    assert_true File.exist?(File.join(prj.bin_dir, 'testpack-adder'))
+
+    # source_dir is deleted by user
+    FileUtils.remove_dir(File.join(prj.bin_dir, 'testpack-adder'), true)
+    assert_false File.exist?(File.join(prj.bin_dir, 'testpack-adder'))
+
+    # configure and build with missing source_dir to fetch new content
+    assert_success prj.configure
+    assert_success prj.build
+
+    # source_dir is populated
+    assert_true File.exist?(File.join(prj.bin_dir, 'testpack-adder'))
+  end
+
+end