CPM_DIRECTORY always stores absolute non symlink paths (#379)

* CPM_DIRECTORY always stores absolute non symlink paths

When CPM is brought into a project via downloading it will be placed
in the build directory. When the build directory is a symlink the
CPM_DIRECTORY value will hold the symlink value. This means that
trying to run CMake via the real build directory will cause CPM
to fail since it considers the current CMAKE_CURRENT_LIST_DIR
to be different and will early exit.

This resolves the issue be always getting CMake to resolve symlinks
before comparing paths for CPM_DIRECTORY.

* Refactor logic based on PR review

README.md

@@ -227,6 +227,22 @@ cmake --build build --target cpm-update-package-lock
 
 See the [wiki](https://github.com/cpm-cmake/CPM.cmake/wiki/Package-lock) for more info.
 
+## Private repositories and CI
+
+When using CPM.cmake with private repositories, there may be a need to provide an [access token](https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token) to be able to clone other projects. Instead of providing the token in CMake, we recommend to provide the regular URL and use [git-config](https://git-scm.com/docs/git-config) to rewrite the URLs to include the token.
+
+As an example, you could include one of the following in your CI script.
+
+```bash
+# Github
+git config --global url."https://${USERNAME}:${TOKEN}@github.com".insteadOf "https://github.com"
+```
+
+```bash
+# GitLab
+git config --global url."https://gitlab-ci-token:${CI_JOB_TOKEN}@gitlab.com".insteadOf "https://gitlab.com"
+```
+
 ## Built with CPM.cmake
 
 Some amazing projects that are built using the CPM.cmake package manager.
@@ -258,6 +274,22 @@ If you know others, feel free to add them here through a PR.
         <p align="center"><b>ModernCppStarter</b></p>
       </a>
     </td>
+    <td>
+      <a href="https://git.io/liblava">
+        <p align="center">
+          <img src="https://github.com/liblava.png" alt="liblava" width="100pt" />
+        </p>
+        <p align="center"><b>liblava - Modern Vulkan library</b></p>
+      </a>
+    </td>
+    <td>
+      <a href="https://github.com/variar/klogg">
+        <p align="center">
+          <img src="https://github.com/variar/klogg/blob/master/src/app/images/hicolor/scalable/klogg.svg" alt="klogg" width="100pt" />
+        </p>
+        <p align="center"><b>klogg - fast advanced log explorer</b></p>
+      </a>
+    </td>
   </tr>
 </table>
 
@@ -275,7 +307,7 @@ CPMAddPackage("gh:catchorg/Catch2@2.5.0")
 ### [Range-v3](https://github.com/ericniebler/range-v3)
 
 ```Cmake
-CPMAddPackage("gh:ericniebler/range-v3#0.11.0")
+CPMAddPackage("gh:ericniebler/range-v3#0.12.0")
 ```
 
 ### [Yaml-cpp](https://github.com/jbeder/yaml-cpp)

cmake/CPM.cmake

@@ -30,8 +30,9 @@ cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
 set(CURRENT_CPM_VERSION 1.0.0-development-version)
 
+get_filename_component(CPM_CURRENT_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}" REALPATH)
 if(CPM_DIRECTORY)
-  if(NOT CPM_DIRECTORY STREQUAL CMAKE_CURRENT_LIST_DIR)
+  if(NOT CPM_DIRECTORY STREQUAL CPM_CURRENT_DIRECTORY)
     if(CPM_VERSION VERSION_LESS CURRENT_CPM_VERSION)
       message(
         AUTHOR_WARNING
@@ -93,7 +94,7 @@ set(CPM_VERSION
     CACHE INTERNAL ""
 )
 set(CPM_DIRECTORY
-    ${CMAKE_CURRENT_LIST_DIR}
+    ${CPM_CURRENT_DIRECTORY}
     CACHE INTERNAL ""
 )
 set(CPM_FILE
@@ -433,6 +434,47 @@ function(cpm_check_git_working_dir_is_clean repoPath gitTag isClean)
 
 endfunction()
 
+# method to overwrite internal FetchContent properties, to allow using CPM.cmake to overload
+# FetchContent calls. As these are internal cmake properties, this method should be used carefully
+# and may need modification in future CMake versions. Source:
+# https://github.com/Kitware/CMake/blob/dc3d0b5a0a7d26d43d6cfeb511e224533b5d188f/Modules/FetchContent.cmake#L1152
+function(cpm_override_fetchcontent contentName)
+  cmake_parse_arguments(PARSE_ARGV 1 arg "" "SOURCE_DIR;BINARY_DIR" "")
+  if(NOT "${arg_UNPARSED_ARGUMENTS}" STREQUAL "")
+    message(FATAL_ERROR "Unsupported arguments: ${arg_UNPARSED_ARGUMENTS}")
+  endif()
+
+  string(TOLOWER ${contentName} contentNameLower)
+  set(prefix "_FetchContent_${contentNameLower}")
+
+  set(propertyName "${prefix}_sourceDir")
+  define_property(
+    GLOBAL
+    PROPERTY ${propertyName}
+    BRIEF_DOCS "Internal implementation detail of FetchContent_Populate()"
+    FULL_DOCS "Details used by FetchContent_Populate() for ${contentName}"
+  )
+  set_property(GLOBAL PROPERTY ${propertyName} "${arg_SOURCE_DIR}")
+
+  set(propertyName "${prefix}_binaryDir")
+  define_property(
+    GLOBAL
+    PROPERTY ${propertyName}
+    BRIEF_DOCS "Internal implementation detail of FetchContent_Populate()"
+    FULL_DOCS "Details used by FetchContent_Populate() for ${contentName}"
+  )
+  set_property(GLOBAL PROPERTY ${propertyName} "${arg_BINARY_DIR}")
+
+  set(propertyName "${prefix}_populated")
+  define_property(
+    GLOBAL
+    PROPERTY ${propertyName}
+    BRIEF_DOCS "Internal implementation detail of FetchContent_Populate()"
+    FULL_DOCS "Details used by FetchContent_Populate() for ${contentName}"
+  )
+  set_property(GLOBAL PROPERTY ${propertyName} TRUE)
+endfunction()
+
 # Download and add a package from source
 function(CPMAddPackage)
   list(LENGTH ARGN argnLength)
@@ -609,6 +651,20 @@ 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 ${CPM_ARGS_UNPARSED_ARGUMENTS})
@@ -644,8 +700,15 @@ function(CPMAddPackage)
         "${${CPM_ARGS_NAME}_SOURCE_DIR}/${CPM_ARGS_SOURCE_SUBDIR}" "${${CPM_ARGS_NAME}_BINARY_DIR}"
         "${CPM_ARGS_EXCLUDE_FROM_ALL}" "${CPM_ARGS_OPTIONS}"
       )
-      set(CPM_SKIP_FETCH TRUE)
       set(PACKAGE_INFO "${PACKAGE_INFO} at ${download_directory}")
+
+      # As the source dir is already cached/populated, we override the call to FetchContent.
+      set(CPM_SKIP_FETCH TRUE)
+      cpm_override_fetchcontent(
+        "${lower_case_name}" SOURCE_DIR "${${CPM_ARGS_NAME}_SOURCE_DIR}/${CPM_ARGS_SOURCE_SUBDIR}"
+        BINARY_DIR "${${CPM_ARGS_NAME}_BINARY_DIR}"
+      )
+
     else()
       # Enable shallow clone when GIT_TAG is not a commit hash. Our guess may not be accurate, but
       # it should guarantee no commit hash get mis-detected.

examples/range-v3/CMakeLists.txt

@@ -6,7 +6,7 @@ project(CPMRangev3Example)
 
 include(../../cmake/CPM.cmake)
 
-CPMAddPackage("gh:ericniebler/range-v3#0.11.0")
+CPMAddPackage("gh:ericniebler/range-v3#0.12.0")
 
 # ---- Executable ----
 

test/integration/test_fetchcontent_compatibility.rb

@@ -0,0 +1,43 @@
+require_relative './lib'
+
+# Tests FetchContent overriding with CPM
+
+class FetchContentCompatibility < IntegrationTest
+  def setup
+    @cache_dir = File.join(cur_test_dir, 'cpmcache')
+    ENV['CPM_SOURCE_CACHE'] = @cache_dir
+  end
+
+  def test_add_dependency_cpm_and_fetchcontent
+    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"
+      )
+
+      # should have no effect, as we added the dependency using CPM
+      FetchContent_Declare(
+        testpack-adder
+        GIT_REPOSITORY https://github.com/cpm-cmake/testpack-adder
+        GIT_TAG v1.0.0
+      )
+      FetchContent_MakeAvailable(testpack-adder)
+    PACK
+
+    # configure with unpopulated cache
+    assert_success prj.configure
+    assert_success prj.build
+
+    # cache is populated
+    assert_true File.exist?(File.join(@cache_dir, "testpack-adder"))
+
+    # configure with populated cache
+    assert_success prj.configure
+    assert_success prj.build
+  end
+
+end

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