prevent overriding declarations (#127)

* add scope protection

* rename to cpm_clean_argument_scope and update patch version

* undo unnecessary scope cleaning

* undo some changes

* consistent define checks

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.
@@ -137,6 +137,35 @@ CPM can be configured to use `find_package` to search for locally installed depe
 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.
 
+## 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 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
 
 These examples demonstrate how to include some well-known projects with CPM.

cmake/CPM.cmake

@@ -28,7 +28,7 @@
 
 cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
-set(CURRENT_CPM_VERSION 0.25.1)
+set(CURRENT_CPM_VERSION 0.26.2)
 
 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
@@ -206,9 +204,6 @@ 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 +212,11 @@ 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 +227,7 @@ 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()
 
@@ -243,12 +238,24 @@ function(CPMAddPackage)
     return()
   endif()
 
+  # Check for manual overrides
+  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 (DEFINED "CPM_DECLARATION_${CPM_ARGS_NAME}" AND NOT "${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})
-    set(CPM_DECLARATION_${CPM_ARGS_NAME} "${declaration}")
     cpm_export_variables(${CPM_ARGS_NAME})
     # checking again to ensure version and option compatibility
     CPMCheckIfPackageAlreadyAdded(${CPM_ARGS_NAME} "${CPM_ARGS_VERSION}" "${CPM_ARGS_OPTIONS}")
@@ -268,7 +275,7 @@ 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})
@@ -279,13 +286,15 @@ function(CPMAddPackage)
 
   if (DEFINED CPM_ARGS_GIT_TAG)
     set(PACKAGE_INFO "${CPM_ARGS_GIT_TAG}")
+  elseif (DEFINED CPM_ARGS_SOURCE_DIR)
+    set(PACKAGE_INFO "${CPM_ARGS_SOURCE_DIR}")
   else()
     set(PACKAGE_INFO "${CPM_ARGS_VERSION}")
   endif()
 
   if (DEFINED CPM_ARGS_DOWNLOAD_COMMAND)
     list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS DOWNLOAD_COMMAND ${CPM_ARGS_DOWNLOAD_COMMAND})
-  elseif(DEFINED CPM_ARGS_SOURCE_DIR)
+  elseif (DEFINED CPM_ARGS_SOURCE_DIR)
     list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS SOURCE_DIR ${CPM_ARGS_SOURCE_DIR})
   elseif (CPM_SOURCE_CACHE)
     string(TOLOWER ${CPM_ARGS_NAME} lower_case_name)
@@ -317,12 +326,12 @@ 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
@@ -345,7 +354,8 @@ 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/package-lock.cmake

@@ -45,4 +45,5 @@ ASSERT_NOT_EXISTS(${CMAKE_CURRENT_LIST_DIR}/test_project/package-lock.cmake)
 updatePackageLock()
 ASSERT_EXISTS(${CMAKE_CURRENT_LIST_DIR}/test_project/package-lock.cmake)
 configureWithDeclare(NO)
+execute_process(COMMAND ${CMAKE_COMMAND} -E rm -f ${CMAKE_CURRENT_LIST_DIR}/test_project/package-lock.cmake)
 

test/unit/package-override.cmake

@@ -0,0 +1,20 @@
+
+include(CMakePackageConfigHelpers)
+include(${CPM_PATH}/testing.cmake)
+
+set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/project-override)
+
+execute_process(COMMAND ${CMAKE_COMMAND} -E rm -rf ${TEST_BUILD_DIR})
+
+configure_package_config_file(
+  "${CMAKE_CURRENT_LIST_DIR}/test_project/OverrideCMakeLists.txt.in"
+  "${CMAKE_CURRENT_LIST_DIR}/test_project/CMakeLists.txt"
+  INSTALL_DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/junk
+)
+
+execute_process(
+  COMMAND ${CMAKE_COMMAND} -H${CMAKE_CURRENT_LIST_DIR}/test_project -B${TEST_BUILD_DIR} -DCPM_Dependency_SOURCE=${CMAKE_CURRENT_LIST_DIR}/test_project/dependency
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")

test/unit/test_project/OverrideCMakeLists.txt.in

@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMTest)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(@CPM_PATH@/CPM.cmake)
+
+CPMAddPackage(
+  NAME Dependency
+)
+
+# ---- Call dependency method to validate correct addition of directory ----
+
+dependency_function()