Add NO_CACHE option (#128)

* add NO_CACHE option

* add unit test

README.md

@@ -105,7 +105,7 @@ Dependencies using CPM will automatically use the updated script of the outermos
 
 - **No pre-built binaries** For every new build directory, all dependencies are initially downloaded and built from scratch. To avoid extra downloads it is recommend to set the [`CPM_SOURCE_CACHE`](#CPM_SOURCE_CACHE) environmental variable. Using a caching compiler such as [ccache](https://github.com/TheLartians/Ccache.cmake) can drastically reduce build time.
 - **Dependent on good CMakeLists** Many libraries do not have CMakeLists that work well for subprojects. Luckily this is slowly changing, however, until then, some manual configuration may be required (see the snippets [below](#snippets) for examples). For best practices on preparing projects for CPM, see the [wiki](https://github.com/TheLartians/CPM.cmake/wiki/Preparing-projects-for-CPM.cmake). 
-- **First version used** In diamond-shaped dependency graphs (e.g. `A` depends on `C`@1.1 and `B`, which itself depends on `C`@1.2 the first added dependency will be used (in this case `C`@1.1). In this case, B requires a newer version of `C` than `A`, so CPM will emit a warning. This can be easily resolved by adding a new version of the dependency in the outermost project, or by introducing a [package lock file](https://github.com/TheLartians/CPM.cmake/wiki/Package-lock).
+- **First version used** In diamond-shaped dependency graphs (e.g. `A` depends on `C`@1.1 and `B`, which itself depends on `C`@1.2 the first added dependency will be used (in this case `C`@1.1). In this case, B requires a newer version of `C` than `A`, so CPM will emit a warning. This can be easily resolved by adding a new version of the dependency in the outermost project, or by introducing a [package lock file](#package-lock).
 
 For projects with more complex needs and where an extra setup step doesn't matter, it may be worth to check out an external C++ package manager such as [vcpkg](https://github.com/microsoft/vcpkg), [conan](https://conan.io) or [hunter](https://github.com/ruslo/hunter).
 Dependencies added with `CPMFindPackage` should work with external package managers.
@@ -139,9 +139,32 @@ These options can also be set as environmental variables.
 
 ## Local package override
 
-Library developers are often in the situation where they work on a locally checked out dependency at the same time as on a consumer.
-It is possible to override the consumer's dependency version with the local one by supplying the CMake option `CPM_<dependency name>_SOURCE`.
-For example, to use the local version of `Dep` at the absolute path `/path/to/dep`, the consumer can be build with `cmake -H. -Bbuild -DCPM_Dep_SOURCE=/path/to/dep`.
+Library developers are often in the situation where they work on a locally checked out dependency at the same time as on a consumer project.
+It is possible to override the consumer's dependency with the version by supplying the CMake option `CPM_<dependency name>_SOURCE` set to the absolute path of the local library.
+For example, to use the local version of the dependency `Dep` at the path `/path/to/dep`, the consumer can be built with the following command. 
+
+```bash
+cmake -Bbuild -DCPM_Dep_SOURCE=/path/to/dep
+```
+
+## Package lock
+
+In large projects with many transitive dependencies, it can be useful to introduce a package lock file.
+This will list all CPM.cmake dependencies and can be used to update dependencies without modifying the original `CMakeLists.txt`.
+To use a package lock, add the following line directly after including CPM.cmake.
+
+```cmake
+CPMUsePackageLock(package-lock.cmake)
+```
+
+To create or update the package lock file, build the `cpm-update-package-lock` target.
+
+```bash
+cmake -Bbuild
+cmake --build build --target cpm-update-package-lock
+```
+
+See the [wiki](https://github.com/TheLartians/CPM.cmake/wiki/Package-lock) for more info.
 
 ## Snippets
 

cmake/CPM.cmake

@@ -28,7 +28,7 @@
 
 cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
-set(CURRENT_CPM_VERSION 0.26)
+set(CURRENT_CPM_VERSION 0.27)
 
 if(CPM_DIRECTORY)
   if(NOT CPM_DIRECTORY STREQUAL CMAKE_CURRENT_LIST_DIR)
@@ -128,9 +128,6 @@ function(CPMFindPackage)
     if (DEFINED CPM_ARGS_GIT_TAG) 
       cpm_get_version_from_git_tag("${CPM_ARGS_GIT_TAG}" CPM_ARGS_VERSION)
     endif()
-    if (NOT DEFINED CPM_ARGS_VERSION) 
-      set(CPM_ARGS_VERSION 0)
-    endif()
   endif()
 
   if (CPM_DOWNLOAD_ALL)
@@ -158,13 +155,13 @@ endfunction()
 function(CPMCheckIfPackageAlreadyAdded CPM_ARGS_NAME CPM_ARGS_VERSION CPM_ARGS_OPTIONS)
   if ("${CPM_ARGS_NAME}" IN_LIST CPM_PACKAGES)
     CPMGetPackageVersion(${CPM_ARGS_NAME} CPM_PACKAGE_VERSION)
-    if(${CPM_PACKAGE_VERSION} VERSION_LESS ${CPM_ARGS_VERSION})
+    if("${CPM_PACKAGE_VERSION}" VERSION_LESS "${CPM_ARGS_VERSION}")
       message(WARNING "${CPM_INDENT} requires a newer version of ${CPM_ARGS_NAME} (${CPM_ARGS_VERSION}) than currently included (${CPM_PACKAGE_VERSION}).")
     endif()
     if (CPM_ARGS_OPTIONS)
       foreach(OPTION ${CPM_ARGS_OPTIONS})
         cpm_parse_option(${OPTION})
-        if(NOT "${${OPTION_KEY}}" STREQUAL ${OPTION_VALUE})
+        if(NOT "${${OPTION_KEY}}" STREQUAL "${OPTION_VALUE}")
           message(WARNING "${CPM_INDENT} ignoring package option for ${CPM_ARGS_NAME}: ${OPTION_KEY} = ${OPTION_VALUE} (${${OPTION_KEY}})")
         endif()
       endforeach()
@@ -183,6 +180,7 @@ function(CPMAddPackage)
 
   set(oneValueArgs
     NAME
+    FORCE
     VERSION
     GIT_TAG
     DOWNLOAD_ONLY
@@ -192,6 +190,7 @@ function(CPMAddPackage)
     SOURCE_DIR
     DOWNLOAD_COMMAND
     FIND_PACKAGE_ARGUMENTS
+    NO_CACHE
   )
 
   set(multiValueArgs
@@ -206,9 +205,6 @@ function(CPMAddPackage)
     if (DEFINED CPM_ARGS_GIT_TAG) 
       cpm_get_version_from_git_tag("${CPM_ARGS_GIT_TAG}" CPM_ARGS_VERSION)
     endif()
-    if (NOT DEFINED CPM_ARGS_VERSION) 
-      set(CPM_ARGS_VERSION 0)
-    endif()
   endif()
 
   if(CPM_ARGS_DOWNLOAD_ONLY)
@@ -217,11 +213,11 @@ function(CPMAddPackage)
     set(DOWNLOAD_ONLY NO)
   endif()
 
-  if (CPM_ARGS_GITHUB_REPOSITORY)
+  if (DEFINED CPM_ARGS_GITHUB_REPOSITORY)
     set(CPM_ARGS_GIT_REPOSITORY "https://github.com/${CPM_ARGS_GITHUB_REPOSITORY}.git")
   endif()
 
-  if (CPM_ARGS_GITLAB_REPOSITORY)
+  if (DEFINED CPM_ARGS_GITLAB_REPOSITORY)
     list(CPM_ARGS_GIT_REPOSITORY "https://gitlab.com/${CPM_ARGS_GITLAB_REPOSITORY}.git")
   endif()
 
@@ -232,7 +228,7 @@ function(CPMAddPackage)
     endif()
   endif()
 
-  if (CPM_ARGS_GIT_TAG)
+  if (DEFINED CPM_ARGS_GIT_TAG)
     list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS GIT_TAG ${CPM_ARGS_GIT_TAG})
   endif()
 
@@ -244,19 +240,20 @@ function(CPMAddPackage)
   endif()
 
   # Check for manual overrides
-  if (NOT "${CPM_${CPM_ARGS_NAME}_SOURCE}" STREQUAL "")
+  if (NOT CPM_ARGS_FORCE AND NOT "${CPM_${CPM_ARGS_NAME}_SOURCE}" STREQUAL "")
     set(PACKAGE_SOURCE ${CPM_${CPM_ARGS_NAME}_SOURCE})
     set(CPM_${CPM_ARGS_NAME}_SOURCE "")
     CPMAddPackage(
       NAME ${CPM_ARGS_NAME}
       SOURCE_DIR ${PACKAGE_SOURCE}
+      FORCE True
     )
     cpm_export_variables(${CPM_ARGS_NAME})
     return()
   endif()
 
   # Check for available declaration
-  if (NOT "${CPM_DECLARATION_${CPM_ARGS_NAME}}" STREQUAL "")
+  if (NOT CPM_ARGS_FORCE AND NOT "${CPM_DECLARATION_${CPM_ARGS_NAME}}" STREQUAL "")
     set(declaration ${CPM_DECLARATION_${CPM_ARGS_NAME}})
     set(CPM_DECLARATION_${CPM_ARGS_NAME} "")
     CPMAddPackage(${declaration})
@@ -279,7 +276,7 @@ function(CPMAddPackage)
     endif()
   endif()
 
-  CPMRegisterPackage(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION})
+  CPMRegisterPackage("${CPM_ARGS_NAME}" "${CPM_ARGS_VERSION}")
 
   if (CPM_ARGS_OPTIONS)
     foreach(OPTION ${CPM_ARGS_OPTIONS})
@@ -300,7 +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)
@@ -330,12 +327,12 @@ function(CPMAddPackage)
     endif()
   endif()
 
-  cpm_declare_fetch(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION} ${PACKAGE_INFO} ${CPM_ARGS_UNPARSED_ARGUMENTS})
-  cpm_fetch_package(${CPM_ARGS_NAME} ${DOWNLOAD_ONLY})
-  cpm_get_fetch_properties(${CPM_ARGS_NAME})
+  cpm_declare_fetch("${CPM_ARGS_NAME}" "${CPM_ARGS_VERSION}" "${PACKAGE_INFO}" "${CPM_ARGS_UNPARSED_ARGUMENTS}")
+  cpm_fetch_package("${CPM_ARGS_NAME}" "${DOWNLOAD_ONLY}")
+  cpm_get_fetch_properties("${CPM_ARGS_NAME}")
 
   SET(${CPM_ARGS_NAME}_ADDED YES)
-  cpm_export_variables(${CPM_ARGS_NAME})
+  cpm_export_variables("${CPM_ARGS_NAME}")
 endfunction()
 
 # Fetch a previously declared package
@@ -358,7 +355,8 @@ 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_${Name}")
     set("CPM_DECLARATION_${Name}" "${ARGN}")

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 ----