[CMake] How to set environment variables with spaces in commands

[Attila Krasznahorkay]

Hi Ruslan,

Thanks, this is good to know.

I absolutely agree that one needs to avoid using "&&" in the commands themselves. As it also causes problems when you try to use CTEST_USE_LAUNCHERS=1. (I myself ran into that issue...)

But I did not have any issues so far with putting "whatever" into a shell script that I then later execute. This is how I got around not being able to use wildcards in some installation commands for instance.

However, I quite like your solution of using a CMake script instead of a *nix shell one. As that should be indeed much more portable. Even if my current project will not work on Windows for a lot of reasons anyway...

Cheers,
              Attila

> On 10 Dec 2015, at 13:38, Ruslan Baratov <ruslan_baratov at yahoo.com> wrote:
> 
> On 10-Dec-15 12:52, Attila Krasznahorkay wrote:
>> Hi QP,
>> 
>> Probably not the intended solution, but what I’m doing in such cases is that in a patch step I create a shell script that does the configuration for me. With all the environment settings and everything. Like:
>> 
>> PATCH_COMMAND ${CMAKE_COMMAND} -E echo “cd someDir/; CC=\”something\” ./configure” > configure.sh
>> CONFIGURE_COMMAND sh configure.sh
>> 
> ...
> 
>> Unfortunately this makes the code quite unportable, as it will only work on POSIX platforms like this.
> Even on *nix platforms such code will not always works as expected. As documentation states (https://cmake.org/cmake/help/v3.4/module/ExternalProject.html):
> Behavior of shell operators like && is not defined.
> I've hit this on practice by using `LOG_* 1` feature. You can try this example (I've moved PATCH_COMMAND to CONFIGURE_COMMAND since there is no LOG_PATCH option):
> 
> https://gist.github.com/ruslo/e8c7be03521f167ae8f0
> 
> Result:
> [ 62%] Performing configure step for 'Foo'
> cd /.../Foo-prefix/src/Foo-build && /.../cmake -P /.../Foo-prefix/src/Foo-stamp/Foo-configure-.cmake
> CMake Error at /.../Foo-prefix/src/Foo-stamp/Foo-configure-.cmake:16 (message):
>   Command failed: 1
> The reason of the failure is because CMake collect all arguments into one command and run execute_process:
> set(command "/.../cmake;-E;echo;cd ..;>;configure.sh")
> execute_process(COMMAND ${command} RESULT_VARIABLE result)
> which of course doesn't make sense.
> 
> This makes writing ExternalProject_Add steps with modification of environment quite non-trivial task (at least doing it correctly). This feature definitely missing in CMake. I've mentioned it once already: https://cmake.org/pipermail/cmake-developers/2015-August/026053.html
> 
> but I've changed my mind about the approach because of LOG_* issue. Now I do the next:
> 
> * wrap each step with CMake script, i.e. instead of `CC=something ./configure` do
> set(ENV{CC} "something")
> execute_process(COMMAND ./configure ...)
> * run CMake script in *_COMMAND:
> 
> CONFIGURE_COMMAND
> "${CMAKE_COMMAND}" -P "/path/to/configure.cmake"
> This makes it cross-platform and *_LOG friendly but require more tricks. Like if you're building in source (non-cmake packages) you have to copy script before execution since CMake will remove source directory on DOWNLOAD step. Which makes it looks like this:
> 
> CONFIGURE_COMMAND
> "${CMAKE_COMMAND}" -E copy "/path/to/source/configure.cmake" "/path/to/unpacked/configure.cmake"
> COMMAND
> "${CMAKE_COMMAND}" -P "/path/to/unpacked/configure.cmake"
> 
> PS I'm hitting problems in ExternalProject with environment variables all the time. E.g. at this moment fixing MinGW + Boost: https://github.com/ruslo/hunter/pull/273
> 
> Ruslo
> 
>>  But I guess that’s the case anyway once you start setting environment variables.
>> 
>> Cheers,
>>            Attila
>> 
>> P.S. I often create build.sh and install.sh scripts as well in additional patch commands.
>> 
>> 
>>> On Dec 10, 2015, at 5:35 AM, Qingping Hou <dave2008713 at gmail.com>
>>>  wrote:
>>> 
>>> Hi all,
>>> 
>>> I am trying to setup an ExternalProject in cmake but got stuck in the
>>> configuration step. I am using ccache to speed up the compilation:
>>> 
>>> ```
>>> ExternalProject_Add(
>>>  ...
>>>  CONFIGURE_COMMAND CC="ccache arm-linux-gnueabihf-gcc" ./configure
>>>  ...
>>> )
>>> ```
>>> 
>>> However, when cmake generates the Makefile, it moves the quotes around
>>> and breaks the command:
>>> 
>>> ```
>>> "CC=ccache arm-linux-gnueabihf-gcc" ./configure
>>> ```
>>> 
>>> I have tried various escaping method to try to get it work properly
>>> without any luck. Is this a bug or an unintended feature?
>>> 
>>> Thanks,
>>> QP
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