add removed test cases

Also:
- Support cmake-format on Windows by using auto lione-ending

.cmake-format

@@ -1,6 +1,7 @@
 format:
   tab_size: 2
   line_width: 100
+  line_ending: auto
   dangle_parens: true
 
 parse:

.github/workflows/test.yaml

@@ -17,6 +17,13 @@ jobs:
         # we need at least ruby 2.7 for the tests
         # instead of dealing with installing a modern version of ruby on 2019, we'll just use windows-2022 here
         os: [ubuntu-latest, windows-2022, macos-latest]
+        # we want to ensure compatibility with a recent CMake version as well as the lowest officially supported
+        # legacy version that we define as the default version of the second-latest Ubuntu LTS release currently available
+        cmake_version: ['3.16.3', '3.25.1']
+        exclude:
+          # there seems to be an issue with CMake 3.16 not finding a C++ compiler on windows-2022 
+          - os: windows-2022
+            cmake_version: '3.16.3'
 
     steps:
       - name: clone
@@ -25,14 +32,17 @@ jobs:
       - name: Setup cmake
         uses: jwlawson/actions-setup-cmake@v1.13
         with:
-          cmake-version: '3.25.x'
+          cmake-version: ${{ matrix.cmake_version }}
 
       - name: unit tests
         run: |
           cmake -Stest -Bbuild/test
           cmake --build build/test --target test-verbose
+        env:
+          CMAKE_VERSION: ${{ matrix.cmake_version }}
 
       - name: integration tests
         run: ruby test/integration/runner.rb
         env:
           CPM_INTEGRATION_TEST_DIR: ./build/integration
+          CMAKE_VERSION: ${{ matrix.cmake_version }}

README.md

@@ -45,6 +45,18 @@ target_link_libraries(main fmt::fmt nlohmann_json::nlohmann_json Catch2::Catch2W
 
 See the [examples directory](https://github.com/cpm-cmake/CPM.cmake/tree/master/examples) for complete examples with source code and check [below](#snippets) or in the [wiki](https://github.com/cpm-cmake/CPM.cmake/wiki/More-Snippets) for example snippets.
 
+## Adding CPM
+
+To add CPM to your current project, simply add the [latest release](https://github.com/cpm-cmake/CPM.cmake/releases/latest) of `CPM.cmake` or `get_cpm.cmake` to your project's `cmake` directory.
+The command below will perform this automatically.
+
+```bash
+mkdir -p cmake
+wget -O cmake/CPM.cmake https://github.com/cpm-cmake/CPM.cmake/releases/latest/download/get_cpm.cmake
+```
+
+You can also download CPM.cmake directly from your project's `CMakeLists.txt`. See the [wiki](https://github.com/cpm-cmake/CPM.cmake/wiki/Downloading-CPM.cmake-in-CMake) for more details.
+
 ## Usage
 
 After `CPM.cmake` has been [added](#adding-cpm) to your project, the function `CPMAddPackage` can be used to fetch and configure a dependency.
@@ -83,7 +95,7 @@ CPMAddPackage("uri#tag")
 CPMAddPackage("uri@version#tag")
 ```
 
-In the shorthand syntax if the URI is of the form `gh:user/name`, it is interpreted as GitHub URI and converted to `https://github.com/user/name.git`. If the URI is of the form `gl:user/name`, it is interpreted as a [GitLab](https://gitlab.com/explore/) URI and converted to `https://gitlab.com/user/name.git`. If the URI is of the form `bb:user/name`, it is interpreted as a [Bitbucket](https://bitbucket.org/) URI and converted to `https://bitbucket.org/user/name.git`. Otherwise the URI used verbatim as a git URL. All packages added using the shorthand syntax will be added using the [EXCLUDE_FROM_ALL](https://cmake.org/cmake/help/latest/prop_tgt/EXCLUDE_FROM_ALL.html) flag.
+In the shorthand syntax if the URI is of the form `gh:user/name`, it is interpreted as GitHub URI and converted to `https://github.com/user/name.git`. If the URI is of the form `gl:user/name`, it is interpreted as a [GitLab](https://gitlab.com/explore/) URI and converted to `https://gitlab.com/user/name.git`. If the URI is of the form `bb:user/name`, it is interpreted as a [Bitbucket](https://bitbucket.org/) URI and converted to `https://bitbucket.org/user/name.git`. Otherwise the URI used verbatim as a git URL. All packages added using the shorthand syntax will be added using the [EXCLUDE_FROM_ALL](https://cmake.org/cmake/help/latest/prop_tgt/EXCLUDE_FROM_ALL.html) and [SYSTEM](https://cmake.org/cmake/help/latest/prop_tgt/SYSTEM.html#prop_tgt:SYSTEM) flag.
 
 The single-argument syntax also works for URLs:
 
@@ -107,21 +119,9 @@ For using CPM.cmake projects with external package managers, such as conan or vc
 
 In rare cases, this behaviour may be desirable by default. The function `CPMFindPackage` will try to find a local dependency via CMake's `find_package` and fallback to `CPMAddPackage`, if the dependency is not found.
 
-## Adding CPM
-
-To add CPM to your current project, simply add the [latest release](https://github.com/cpm-cmake/CPM.cmake/releases/latest) of `CPM.cmake` or `get_cpm.cmake` to your project's `cmake` directory.
-The command below will perform this automatically.
-
-```bash
-mkdir -p cmake
-wget -O cmake/CPM.cmake https://github.com/cpm-cmake/CPM.cmake/releases/latest/download/get_cpm.cmake
-```
-
-You can also download CPM.cmake directly from your project's `CMakeLists.txt`. See the [wiki](https://github.com/cpm-cmake/CPM.cmake/wiki/Downloading-CPM.cmake-in-CMake) for more details.
-
 ## Updating CPM
 
-To update CPM to the newest version, update the script in the project's root directory, for example by running the command above.
+To update CPM to the newest version, update the script in the project's root directory, for example by running the same command as for [adding CPM](#adding-cpm).
 Dependencies using CPM will automatically use the updated script of the outermost project.
 
 ## Advantages
@@ -199,11 +199,14 @@ This can be controlled on a per package basis with the `CPM_DOWNLOAD_<dependency
 ### CPM_USE_LOCAL_PACKAGES
 
 CPM can be configured to use `find_package` to search for locally installed dependencies first by setting the CMake option `CPM_USE_LOCAL_PACKAGES`.
+
 If the option `CPM_LOCAL_PACKAGES_ONLY` is set, CPM will emit an error if the dependency is not found locally.
 These options can also be set as environmental variables.
 
 In the case that `find_package` requires additional arguments, the parameter `FIND_PACKAGE_ARGUMENTS` may be specified in the `CPMAddPackage` call. The value of this parameter will be forwarded to `find_package`.
 
+Note that this does not apply to dependencies that have been defined with a truthy `FORCE` parameter. These will be added as defined.
+
 ### CPM_USE_NAMED_CACHE_DIRECTORIES
 
 If set, CPM use additional directory level in cache to improve readability of packages names in IDEs like CLion. It changes cache structure, so all dependencies are downloaded again. There is no problem to mix both structures in one cache directory but then there may be 2 copies of some dependencies.

cmake/CPM.cmake

@@ -505,6 +505,60 @@ function(cpm_override_fetchcontent contentName)
   set_property(GLOBAL PROPERTY ${propertyName} TRUE)
 endfunction()
 
+# replaces empty arguments with a placeholder to compensate CMake issues with handling empty
+# arguments
+function(cpm_encode_empty_arguments args outVar)
+  set(out "")
+  # note: we don't use string replacement for ';;' -> ';__CPM_EMPTY_ARG;' here, as it would
+  # interfere with nested arguments
+  foreach(ARG IN LISTS args)
+    if(NOT out STREQUAL "")
+      string(APPEND out ";")
+    endif()
+    if(ARG STREQUAL "")
+      string(APPEND out "__CPM_EMPTY_ARG")
+    else()
+      # prevent escaped characters from getting resolved early
+      string(REPLACE "\\" "\\\\\\" ARG "${ARG}")
+      string(APPEND out "${ARG}")
+    endif()
+  endforeach()
+  set("${outVar}"
+      "${out}"
+      PARENT_SCOPE
+  )
+endfunction()
+
+function(cpm_decode_empty_argument arg outVar)
+  if("${arg}" STREQUAL "__CPM_EMPTY_ARG")
+    set("${outVar}"
+        ""
+        PARENT_SCOPE
+    )
+  else()
+    set("${outVar}"
+        "${arg}"
+        PARENT_SCOPE
+    )
+  endif()
+endfunction()
+
+# replaces placeholder arguments from `cpm_encode_empty_arguments` with empty arguments
+function(cpm_decode_empty_arguments args outVar)
+  set(out "")
+  foreach(ARG IN LISTS args)
+    if(NOT out STREQUAL "")
+      string(APPEND out ";")
+    endif()
+    cpm_decode_empty_argument("${ARG}" ARG)
+    string(APPEND out "${ARG}")
+  endforeach()
+  set("${outVar}"
+      "${out}"
+      PARENT_SCOPE
+  )
+endfunction()
+
 # Download and add a package from source
 function(CPMAddPackage)
   cpm_set_policies()
@@ -512,7 +566,6 @@ function(CPMAddPackage)
   list(LENGTH ARGN argnLength)
   if(argnLength EQUAL 1)
     cpm_parse_add_package_single_arg("${ARGN}" ARGN)
-
     # The shorthand syntax implies EXCLUDE_FROM_ALL and SYSTEM
     set(ARGN "${ARGN};EXCLUDE_FROM_ALL;YES;SYSTEM;YES;")
   endif()
@@ -539,10 +592,26 @@ function(CPMAddPackage)
 
   set(multiValueArgs URL OPTIONS)
 
-  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" "${ARGN}")
+  # Encode arguments for `cmake_parse_arguments`
+  cpm_encode_empty_arguments("${ARGN}" "PARSE_ARGS")
+
+  # Parse arguments
+  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" "${PARSE_ARGS}")
+
+  # Decode arguments
+  foreach(ARG IN LISTS oneValueArgs)
+    if(DEFINED CPM_ARGS_${ARG})
+      cpm_decode_empty_argument("${CPM_ARGS_${ARG}}" CPM_ARGS_${ARG})
+    endif()
+  endforeach()
+  foreach(ARG IN LISTS multiValueArgs)
+    if(DEFINED CPM_ARGS_${ARG})
+      cpm_decode_empty_arguments("${CPM_ARGS_${ARG}}" CPM_ARGS_${ARG})
+    endif()
+  endforeach()
+  cpm_decode_empty_arguments("${CPM_ARGS_UNPARSED_ARGUMENTS}" CPM_ARGS_UNPARSED_ARGUMENTS)
 
   # Set default values for arguments
-
   if(NOT DEFINED CPM_ARGS_VERSION)
     if(DEFINED CPM_ARGS_GIT_TAG)
       cpm_get_version_from_git_tag("${CPM_ARGS_GIT_TAG}" CPM_ARGS_VERSION)
@@ -648,6 +717,7 @@ function(CPMAddPackage)
     return()
   endif()
 
+  if(NOT CPM_ARGS_FORCE)
     if(CPM_USE_LOCAL_PACKAGES OR CPM_LOCAL_PACKAGES_ONLY)
       cpm_find_package(${CPM_ARGS_NAME} "${CPM_ARGS_VERSION}" ${CPM_ARGS_FIND_PACKAGE_ARGUMENTS})
 
@@ -663,6 +733,7 @@ function(CPMAddPackage)
         )
       endif()
     endif()
+  endif()
 
   CPMRegisterPackage("${CPM_ARGS_NAME}" "${CPM_ARGS_VERSION}")
 
@@ -914,8 +985,7 @@ function(cpm_declare_fetch PACKAGE VERSION INFO)
     cpm_message(STATUS "${CPM_INDENT} Package not declared (dry run)")
     return()
   endif()
-
-  FetchContent_Declare(${PACKAGE} ${ARGN})
+  FetchContent_Declare(${PACKAGE} "${ARGN}")
 endfunction()
 
 # returns properties for a package previously defined by cpm_declare_fetch
@@ -1103,7 +1173,7 @@ function(cpm_prettify_package_arguments OUT_VAR IS_IN_COMMENT)
       GIT_SHALLOW
   )
   set(multiValueArgs OPTIONS)
-  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  cmake_parse_arguments(PARSE_ARGV 2 CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}")
 
   foreach(oneArgName ${oneValueArgs})
     if(DEFINED CPM_ARGS_${oneArgName})

cmake/get_cpm.cmake

@@ -27,6 +27,7 @@ else()
   if("${check}" STREQUAL "")
     download_cpm()
   endif()
+  unset(check)
 endif()
 
 include(${CPM_DOWNLOAD_LOCATION})

test/integration/README.md

@@ -12,7 +12,7 @@ To run all tests from the repo root execute:
 $ ruby test/integration/runner.rb
 ```
 
-The runner will run all tests and generate a report of the exeuction.
+The runner will run all tests and generate a report of the execution.
 
 The current working directory doesn't matter. If you are in `<repo-root>/test/integration`, you can run simply `$ ruby runner.rb`.
 

test/integration/test_system_warnings.rb

@@ -2,6 +2,11 @@ require_relative './lib'
 
 class SystemWarnings < IntegrationTest
   
+  def setup
+    # system is only supported for CMake >= 3.25 
+    @system_supported = (!ENV['CMAKE_VERSION']) || (Gem::Version.new(ENV['CMAKE_VERSION']) >= Gem::Version.new('3.25'))
+  end
+
   def test_dependency_added_using_system
     for use_system in [true, false] do
       prj = make_project name: use_system ? "system" : "no_system", from_template: 'using-adder'
@@ -21,7 +26,7 @@ class SystemWarnings < IntegrationTest
       PACK
 
       assert_success prj.configure
-      if use_system
+      if use_system and @system_supported
         assert_success prj.build
       else
         assert_failure prj.build
@@ -42,7 +47,11 @@ class SystemWarnings < IntegrationTest
     PACK
 
     assert_success prj.configure
+    if @system_supported
       assert_success prj.build
+    else
+      assert_failure prj.build
+    end
   end
 
 end

test/unit/forward_arguments.cmake

@@ -0,0 +1,69 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+include(${CPM_PATH}/CPM.cmake)
+include(${CPM_PATH}/testing.cmake)
+
+set(input "a;;b;c;;;;def;g;;")
+cpm_encode_empty_arguments("${input}" encoded)
+foreach(arg IN LISTS encoded)
+  assert_not_equal("${arg}" "")
+endforeach()
+assert_equal("${contains_empty_arg}" "")
+cpm_decode_empty_arguments("${encoded}" decoded)
+assert_equal("${decoded}" "${input}")
+
+# ignore source cache if set
+set(CPM_SOURCE_CACHE "")
+
+# Intercept underlying `FetchContent_Declare`
+function(FetchContent_Declare)
+  set_property(GLOBAL PROPERTY last_FetchContent_Declare_ARGN "${ARGN}")
+endfunction()
+cpm_declare_fetch(PACKAGE VERSION INFO EMPTY "" ANOTHER)
+
+# TEST:`cpm_declare_fetch` shall forward empty arguments
+get_property(last_FetchContent_Declare_ARGN GLOBAL PROPERTY last_FetchContent_Declare_ARGN)
+assert_equal("${last_FetchContent_Declare_ARGN}" "PACKAGE;EMPTY;;ANOTHER")
+
+# TEST:`CPMDeclarePackage` shall store all including empty
+CPMDeclarePackage(FOO EMPTY "" ANOTHER)
+assert_equal("${CPM_DECLARATION_FOO}" "EMPTY;;ANOTHER")
+
+# Stub the actual fetch
+set(fibonacci_POPULATED YES)
+set(fibonacci_SOURCE_DIR ".")
+set(fibonacci_BINARY_DIR ".")
+macro(FetchContent_GetProperties)
+
+endmacro()
+
+# TEST:`CPMAddPackage` shall call `FetchContent_declare` with unmodified arguments including any
+# Empty-string arguments
+CPMAddPackage(
+  NAME fibonacci
+  GIT_REPOSITORY https://github.com/cpm-cmake/testpack-fibonacci.git
+  VERSION 1.2.3 EMPTY_OPTION "" COMMAND_WITH_EMPTY_ARG foo "" bar
+)
+get_property(last_FetchContent_Declare_ARGN GLOBAL PROPERTY last_FetchContent_Declare_ARGN)
+assert_equal(
+  "${last_FetchContent_Declare_ARGN}"
+  "fibonacci;EMPTY_OPTION;;COMMAND_WITH_EMPTY_ARG;foo;;bar;GIT_REPOSITORY;https://github.com/cpm-cmake/testpack-fibonacci.git;GIT_TAG;v1.2.3"
+)
+
+# Intercept underlying `cpm_add_package_multi_arg`
+function(CPMAddPackage)
+  set_property(GLOBAL PROPERTY last_cpmaddpackage_argn "${ARGN}")
+endfunction()
+
+# TEST: CPM Module file shall store all arguments including empty strings
+include(${CPM_MODULE_PATH}/Findfibonacci.cmake)
+
+get_property(last_cpmaddpackage_argn GLOBAL PROPERTY last_cpmaddpackage_argn)
+assert_equal(
+  "${last_cpmaddpackage_argn}"
+  "NAME;fibonacci;GIT_REPOSITORY;https://github.com/cpm-cmake/testpack-fibonacci.git;VERSION;1.2.3;EMPTY_OPTION;;COMMAND_WITH_EMPTY_ARG;foo;;bar"
+)
+
+# remove generated files
+file(REMOVE_RECURSE ${CPM_MODULE_PATH})
+file(REMOVE ${CPM_PACKAGE_LOCK_FILE})

test/unit/options.cmake

@@ -2,6 +2,8 @@ include(CMakePackageConfigHelpers)
 include(${CPM_PATH}/testing.cmake)
 
 set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/source_dir)
+# clean existing build if it exists
+file(REMOVE_RECURSE "${TEST_BUILD_DIR}")
 
 set(TEST_DEPENDENCY_NAME Dependency)