Add dependencies using EXCLUDE_FROM_ALL flag (#198)

* add dependencies using EXCLUDE_FROM_ALL flag

* respect DOWNLOAD_ONLY flag

* set EXCLUDE_FROM_ALL as an optional flag

* use one value arg for consistency

* fix argument passing

* add unit test

* update cmake-format

.cmake-format

@@ -33,6 +33,7 @@ parse:
         DOWNLOAD_NO_EXTRACT: 1
         HTTP_USERNAME: 1
         HTTP_PASSWORD: 1
+        EXCLUDE_FROM_ALL: 1
         OPTIONS: +
     cpmfindpackage:
       pargs:

cmake/testing.cmake

@@ -10,6 +10,18 @@ function(ASSERT_EQUAL)
   endif()
 endfunction()
 
+function(ASSERT_NOT_EQUAL)
+  if(NOT ARGC EQUAL 2)
+    message(FATAL_ERROR "assertion failed: invalid argument count: ${ARGC}")
+  endif()
+
+  if(${ARGV0} STREQUAL ${ARGV1})
+    message(FATAL_ERROR "assertion failed: '${ARGV0}' == '${ARGV1}'")
+  else()
+    message(STATUS "test passed: '${ARGV0}' != '${ARGV1}'")
+  endif()
+endfunction()
+
 function(ASSERT_EMPTY)
   if(NOT ARGC EQUAL 0)
     message(FATAL_ERROR "assertion failed: input ${ARGC} not empty: '${ARGV}'")

test/unit/broken_dependency/.gitignore

@@ -0,0 +1,2 @@
+/CMakeLists.txt
+/package-lock.cmake

test/unit/broken_dependency/CMakeLists.txt.in

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMTest)
+
+# ---- Dependencies ----
+
+include(@CPM_PATH@/CPM.cmake)
+
+CPMAddPackage(
+  NAME BrokenDependency
+  SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/dependency
+  EXCLUDE_FROM_ALL @EXCLUDE_FROM_ALL@
+)

test/unit/broken_dependency/dependency/CMakeLists.txt

@@ -0,0 +1,3 @@
+project(BrokenDependency)
+
+add_custom_target(error ALL ${CMAKE_COMMAND} -E false)

test/unit/exclude_from_all.cmake

@@ -0,0 +1,35 @@
+include(CMakePackageConfigHelpers)
+include(${CPM_PATH}/testing.cmake)
+
+set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/exclude_from_all)
+
+function(init_project EXCLUDE_FROM_ALL)
+  configure_package_config_file(
+    "${CMAKE_CURRENT_LIST_DIR}/broken_dependency/CMakeLists.txt.in"
+    "${CMAKE_CURRENT_LIST_DIR}/broken_dependency/CMakeLists.txt"
+    INSTALL_DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/junk
+  )
+
+  execute_process(
+    COMMAND ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/broken_dependency" "-B${TEST_BUILD_DIR}"
+    RESULT_VARIABLE ret
+  )
+
+  assert_equal(${ret} "0")
+endfunction()
+
+function(build_project expected_success)
+  execute_process(COMMAND ${CMAKE_COMMAND} "--build" "${TEST_BUILD_DIR}" RESULT_VARIABLE ret)
+
+  if(expected_success)
+    assert_equal(${ret} 0)
+  else()
+    assert_not_equal(${ret} 0)
+  endif()
+endfunction()
+
+init_project(FALSE)
+build_project(FALSE)
+
+init_project(TRUE)
+build_project(TRUE)