Add NO_CACHE option (#128)

* add NO_CACHE option

* add unit test

cmake/CPM.cmake

@@ -28,7 +28,7 @@
 
 cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
-set(CURRENT_CPM_VERSION 0.26.1)
+set(CURRENT_CPM_VERSION 0.27)
 
 if(CPM_DIRECTORY)
   if(NOT CPM_DIRECTORY STREQUAL CMAKE_CURRENT_LIST_DIR)
@@ -190,6 +190,7 @@ function(CPMAddPackage)
     SOURCE_DIR
     DOWNLOAD_COMMAND
     FIND_PACKAGE_ARGUMENTS
+    NO_CACHE
   )
 
   set(multiValueArgs
@@ -296,7 +297,7 @@ 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})
-  elseif (CPM_SOURCE_CACHE)
+  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})
     list(SORT origin_parameters)
@@ -354,9 +355,10 @@ macro(cpm_export_variables name)
 endmacro()
 
 # declares a package, so that any call to CPMAddPackage for the 
-# package name will use these arguments instead 
+# package name will use these arguments instead.
+# Previous declarations will not be overriden.
 macro(CPMDeclarePackage Name)
-  if (NOT DEFINED "${CPM_DECLARATION_${Name}}")
+  if (NOT DEFINED "CPM_DECLARATION_${Name}")
     set("CPM_DECLARATION_${Name}" "${ARGN}")
   endif()
 endmacro()

test/unit/cache.cmake

@@ -3,17 +3,13 @@ cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 include(${CPM_PATH}/testing.cmake)
 include(CMakePackageConfigHelpers)
 
-
 set(CPM_SOURCE_CACHE_DIR "${CMAKE_CURRENT_BINARY_DIR}/CPM")
 set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/cache)
 
 function(clear_cache)
   message(STATUS "clearing CPM cache")
   FILE(REMOVE_RECURSE ${CPM_SOURCE_CACHE_DIR})
-  
-  if (EXISTS "${CPM_SOURCE_CACHE_DIR}")
-    ASSERTION_FAILED("cache not cleared")
-  endif()
+  ASSERT_NOT_EXISTS("${CPM_SOURCE_CACHE_DIR}")
 endfunction()
 
 function(update_cmake_lists)
@@ -43,10 +39,7 @@ execute_process(
 )
 
 ASSERT_EQUAL(${ret} "0")
-
-if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
-  ASSERTION_FAILED("fibonacci not in cache")
-endif()
+ASSERT_EXISTS("${CPM_SOURCE_CACHE_DIR}/fibonacci")
 
 FILE(GLOB FIBONACCI_VERSIONs "${CPM_SOURCE_CACHE_DIR}/fibonacci/*")
 list(LENGTH FIBONACCI_VERSIONs FIBONACCI_VERSION_count)
@@ -84,10 +77,7 @@ execute_process(
 )
 
 ASSERT_EQUAL(${ret} "0")
-
-if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
-  ASSERTION_FAILED("fibonacci not in cache")
-endif()
+ASSERT_EXISTS("${CPM_SOURCE_CACHE_DIR}/fibonacci")
 
 ## Read CPM_SOURCE_CACHE from environment
 
@@ -100,10 +90,7 @@ execute_process(
 )
 
 ASSERT_EQUAL(${ret} "0")
-
-if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
-  ASSERTION_FAILED("fibonacci not in cache")
-endif()
+ASSERT_EXISTS("${CPM_SOURCE_CACHE_DIR}/fibonacci")
 
 ## Reuse cached packages for other build
 
@@ -126,7 +113,19 @@ execute_process(
 )
 
 ASSERT_EQUAL(${ret} "0")
+ASSERT_EXISTS("${CPM_SOURCE_CACHE_DIR}/fibonacci")
 
-if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
-  ASSERTION_FAILED("fibonacci not in cache")
-endif()
+## Use NO_CACHE option
+
+set(FIBONACCI_PACKAGE_ARGS "NO_CACHE YES")
+update_cmake_lists()
+reset_test()
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} -E env "CPM_SOURCE_CACHE=${CPM_SOURCE_CACHE_DIR}" ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/cache" "-B${TEST_BUILD_DIR}"
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")
+ASSERT_NOT_EXISTS("${CPM_SOURCE_CACHE_DIR}/fibonacci")

test/unit/cache/CMakeLists.txt.in

@@ -14,6 +14,7 @@ CPMAddPackage(
   NAME fibonacci
   GIT_REPOSITORY https://github.com/TheLartians/Fibonacci.git
   VERSION @FIBONACCI_VERSION@
+  @FIBONACCI_PACKAGE_ARGS@
 )
 
 # ---- Create binary ----