Preserving forwarding of empty string arguments

.cmake-format

@@ -2,4 +2,5 @@ include: ["cmake/.cmake-format-additional_commands-cpm"]
 format:
   tab_size: 2
   line_width: 100
+  line_ending: auto
   dangle_parens: true

cmake/CPM.cmake

@@ -505,17 +505,50 @@ function(cpm_override_fetchcontent contentName)
   set_property(GLOBAL PROPERTY ${propertyName} TRUE)
 endfunction()
 
+macro(cpm_cmake_eval)
+  set(__ARGN "${ARGN}")
+  if(COMMAND cmake_language)
+    cmake_language(EVAL CODE "${__ARGN}")
+  else()
+    file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/eval.cmake "${__ARGN}")
+    include(${CMAKE_CURRENT_BINARY_DIR}/eval.cmake)
+  endif()
+endmacro()
+
 # Download and add a package from source
-function(CPMAddPackage)
+macro(CPMAddPackage)
+  set(__ARGN "${ARGN}")
+  list(LENGTH __ARGN __ARGN_Length)
+  if(__ARGN_Length EQUAL 1)
+    cpm_add_package_single_arg(${ARGN})
+  else()
+    # Forward preserving empty string arguments
+    # (https://gitlab.kitware.com/cmake/cmake/-/merge_requests/4729)
+    set(__ARGN_Quoted)
+    foreach(__ARG IN LISTS __ARGN)
+      string(APPEND __ARGN_Quoted " [==[${__ARG}]==]")
+    endforeach()
+    cpm_cmake_eval("cpm_add_package_multi_arg( ${__ARGN_Quoted} )")
+  endif()
+endmacro()
+
+macro(cpm_add_package_single_arg arg)
   cpm_set_policies()
+  cpm_parse_add_package_single_arg("${arg}" __ARGN_multi)
 
-  list(LENGTH ARGN argnLength)
-  if(argnLength EQUAL 1)
-    cpm_parse_add_package_single_arg("${ARGN}" ARGN)
+  # The shorthand syntax implies EXCLUDE_FROM_ALL
+  # cmake-format: off
+  list(APPEND __ARGN_multi
+    EXCLUDE_FROM_ALL YES
+    SYSTEM YES
+  )
+  # cmake-format: on
 
-    # The shorthand syntax implies EXCLUDE_FROM_ALL and SYSTEM
-    set(ARGN "${ARGN};EXCLUDE_FROM_ALL;YES;SYSTEM;YES;")
-  endif()
+  cpm_add_package_multi_arg(${__ARGN_multi}) # Forward function arguments to CPMAddPackage()
+endmacro()
+
+function(cpm_add_package_multi_arg)
+  cpm_set_policies()
 
   set(oneValueArgs
       NAME
@@ -538,7 +571,7 @@ function(CPMAddPackage)
 
   set(multiValueArgs URL OPTIONS DOWNLOAD_COMMAND)
 
-  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" "${ARGN}")
+  cmake_parse_arguments(PARSE_ARGV 0 CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}")
 
   # Set default values for arguments
 
@@ -916,7 +949,13 @@ function(cpm_declare_fetch PACKAGE VERSION INFO)
     return()
   endif()
 
-  FetchContent_Declare(${PACKAGE} ${ARGN})
+  # Forward preserving empty string arguments
+  # (https://gitlab.kitware.com/cmake/cmake/-/merge_requests/4729)
+  set(__argsQuoted)
+  foreach(__item IN LISTS ARGN)
+    string(APPEND __argsQuoted " [==[${__item}]==]")
+  endforeach()
+  cpm_cmake_eval("FetchContent_Declare(${PACKAGE} ${__argsQuoted} )")
 endfunction()
 
 # returns properties for a package previously defined by cpm_declare_fetch
@@ -1102,8 +1141,9 @@ function(cpm_prettify_package_arguments OUT_VAR IS_IN_COMMENT)
       SYSTEM
       GIT_SHALLOW
   )
+
   set(multiValueArgs URL OPTIONS DOWNLOAD_COMMAND)
-  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})

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/unit/forward_arguments.cmake

@@ -0,0 +1,58 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+include(${CPM_PATH}/CPM.cmake)
+include(${CPM_PATH}/testing.cmake)
+
+# 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(cpm_add_package_multi_arg)
+  set_property(GLOBAL PROPERTY last_cpm_add_package_multi_arg_ARGN "${ARGN}")
+endfunction()
+
+# TEST: CPM Module file shall store all arguments including empty strings
+include(${CPM_MODULE_PATH}/Findfibonacci.cmake)
+get_property(
+  last_cpm_add_package_multi_arg_ARGN GLOBAL PROPERTY last_cpm_add_package_multi_arg_ARGN
+)
+assert_equal(
+  "${last_cpm_add_package_multi_arg_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})