@audiofanatic I've tried to use the download_project function in a child directory of a project and it doesn't download the external project.

Any tip or hint? thanks!

Since projects are downloaded as source, when a project uses ${CMAKE_SOURCE_DIRECTORY} it uses the source directory of the highest level project and disrupts the resulting paths.

Is this a limitation of this approach, or can this be worked around?

The GTest example actually doesn't work with MSVC 11 (toolset v110) due to VC++ not supporting variadic templates.

The problem can be fixed by defining GTEST_HAS_TR1_TUPLE to 0 or _VARIADIC_MAX to 10, although the latter is more of a band aid than a solution.

This is just a heads up for anyone who might want to use this with an old version of MSVC

When I used your extension as

include(DownloadProject)
download_project(PROJ                googletest
                 GIT_REPOSITORY      https://github.com/google/googletest.git
                 GIT_TAG             master
                 ${UPDATE_DISCONNECTED_IF_AVAILABLE}
)
add_subdirectory(${googletest_SOURCE_DIR} ${googletest_BINARY_DIR})

I have the problem that the downloaded project gets installed as well when my project installs can I somehow disable this?

This is not related to this library but maybe you can help :-)

We use this awesome script to download our 3rdparty repository containing several gigabytes of pre-buillt thirdparty libraries.

However, when we add a new prebuild there and consequently update the referenced version in our main repository's cmake, the whole repository is checked out again (Instead of just downloading the diff). This takes hours for our +20 GB repository, especially via VPN.

Is there a way to achieve just a git pull using DownloadProject or FetchContent?

When I try to use it with a project that requires SSH autentication it is not working. I use the url in the form [email protected]:Crascit/DownloadProject.git but it seems not able to grab the private key. Is it supported?

This fixes an issue with CLion that means that the dependencies get built in the wrong directory due to the CMakeCache.txt being copied between the directories. No adverse effect is caused for other generators.

The UPDATE_DISCONNECTED command is broken in cmake 3.5 and cmake 3.6. Here is the bug report: https://cmake.org/Bug/view.php?id=15904. Currently its use is recommended in your docs:

https://github.com/Crascit/DownloadProject/blob/master/DownloadProject.cmake#L58

Please consider removing this advice.

Hi, very interesting idea and I wanted to get your feedback on a couple ideas.

The first is an issue with an independent generate + build process. I am getting the following error:

gtest.lib(gtest-all.cc.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MTd_StaticDebug' doesn't match value 'MDd_DynamicDebug' in mytest.cpp.obj

My thoughts (not an expert in this area) are the separate execute_process is not pulling in my current CMake options, such as MSVC compile flags. Do you see a convenient way of forwarding these in the DownloadProject.cmake?

2. I don't want these sources in the same folder as my tests. I've roughly injected a static path for this:

include(CMakeParseArguments)

set(DOWNLOAD_PROJECT_DIR ${CMAKE_CURRENT_LIST_DIR})

function(download_project)
...
    configure_file("${DOWNLOAD_PROJECT_DIR}/DownloadProject.CMakeLists.cmake.in" ${DL_ARGS_PROJ}-download/CMakeLists.txt)
...
endfunction()

Curious about your thoughts. Thanks!

I would like to have all the external projects under the same directory. A ThirdParty folder placed at the rood of cmake_binary_dir. When using ExternalProject_Add, this can be done locally to each project using [PREFIX dir] or globally as follows:

# Set default ExternalProject root directory
set_directory_properties(PROPERTIES EP_PREFIX ${CMAKE_BINARY_DIR}/ThirdParty)

However when using DownloadProject, this EP_PREFIX has no effect even when forced like this:

download_project(PROJ                googletest
                 PREFIX "ThirdParty"
                 GIT_REPOSITORY      https://github.com/google/googletest.git
                 GIT_TAG             master
                 ${UPDATE_DISCONNECTED_IF_AVAILABLE}
)

The project is downloaded at ./ThirdParty/googletest-download indeed, but then CMake crushes since ./ThirdParty/googletest-src is not created.

-- Build files have been written to: /tmp/DownloadProject/build/ThirdParty/googletest-download
Scanning dependencies of target googletest-download
[ 11%] Creating directories for 'googletest-download'
[ 22%] Performing download step (git clone) for 'googletest-download'
Cloning into 'googletest-src'...
Already on 'master'
Your branch is up-to-date with 'origin/master'.
[ 33%] No patch step for 'googletest-download'
[ 44%] Skipping update step for 'googletest-download'
[ 55%] No configure step for 'googletest-download'
[ 66%] No build step for 'googletest-download'
[ 77%] No install step for 'googletest-download'
[ 88%] No test step for 'googletest-download'
[100%] Completed 'googletest-download'
[100%] Built target googletest-download
CMake Error at CMakeLists.txt:25 (add_subdirectory):
  add_subdirectory given source "ThirdParty/googletest-src" which is not an
  existing directory.

What am I missing?

I'm trying to automate the download and build of mariadb-connector-c and added this to he CMakeLists.txt where I define my tests (not the one at the root of my project):

download_project(PROJ               mariadb-connector-c
                 GIT_REPOSITORY     https://github.com/MariaDB/mariadb-connector-c
                 GIT_TAG            master
                 ${UPDATE_DISCONNECTED_IF_AVAILABLE}
)
add_subdirectory(${mariadb-connector-c_SOURCE_DIR} ${mariadb-connector-c_BINARY_DIR})

While the source code is downloaded, the result of running CMake on the connector is stored in the -download folder and the product is not built or configured, I need to run cmake manually again.

Is there a way to go around this?

A similar tool was just added to CMake 3.11: the FetchContent module, which downloads content at configure time. I would recommend adding a mention of this module to the README just in case a user is okay with requiring CMake 3.11+.