[CMake] error executing script with cmake -P

[Tom Finegan]

On Thu, Oct 17, 2019 at 2:14 AM Edoardo Pasca <edo.paskino at gmail.com> wrote:

> Hi Tom,
>
> I thought ${testdata} was going to be filled in by the actual
> patch_script.cmake at this line.
>
> file (STRINGS TestData.py testdata NEWLINE_CONSUME)
>

Sorry, some nasty formatting in my email client had me misreading your
script. My advice is mainly based on this error:

  CMake Error at build/patch_script.cmake:3 (string):
    string sub-command REPLACE requires at least four arguments

Looking at this line:
string(REPLACE \"sys.prefix\" \"os.environ[\\\'SIRF_INSTALL_PATH\\\']\"
patched \${testdata})

The most likely possible reason for that error being reported by CMake is
that ${testdata} is not defined when that line of script is executed. What
does line 3 of patch_script.cmake look like immediately after the error
message is output? My guess is that it looks something like this:

  string(REPLACE "sys.prefix" "os.environ[\'SIRF_INSTALL_PATH\']" patched )

As you'll notice REPLACE is only receiving 3 args in the above version.

Also note: I don't think you need to escape the single quotes in the
os.environ argument (unless they must be escaped in the final output).
Basic toy scripts here show it as unnecessary unless they must be escaped
in the patched file.


>
>  So it appears that this command doesn't quite work.
>
> I'll try also Alan's suggestion.
>
> Thanks
>
> Edo
>
> On Tue, Oct 15, 2019 at 7:00 PM Tom Finegan <tomfinegan at google.com> wrote:
>
>> It looks like you aren't passing the $testdata variable down to the
>> script. From your message it looks like you need to add the following to
>> your PATCH_COMMAND:
>>
>> -Dtestdata=${testdata}
>>
>> You must explicitly pass $testdata (and any other variables defined in
>> the calling script) to patch_script.cmake via -D parameters on the command
>> line. Also note that the -Dvar=value args must precede the -P <script>
>> argument for the arguments to be defined in the script.
>>
>> Note: I'm not certain about the rules for ExternalProject_Add. The above
>> is based on the behavior of execute_process(), but the error message you've
>> sent leads me to believe that the problem here is the same: Variables from
>> the calling CMake scope are not automatically passed along to the scope of
>> child CMake instances.
>>
>>
>>
>> On Mon, Oct 14, 2019 at 4:01 AM Edoardo Pasca <edo.paskino at gmail.com>
>> wrote:
>>
>>> Dear all,
>>>
>>> I am using external project. I would like to patch a source file. I came
>>> out with a cmake script that does the string replacement I'm interested in.
>>>
>>> I tested in a standalone project, with the following CMakeLists.txt
>>>
>>> cmake_minimum_required(VERSION 3.4)
>>> project(patching_string)
>>> file (STRINGS TestData.py testdata NEWLINE_CONSUME)
>>> string(REPLACE "sys.prefix" "os.environ[\'SIRF_INSTALL_PATH\']" patched
>>> ${testdata})
>>> file( WRITE ${CMAKE_CURRENT_SOURCE_DIR}/TestData.py ${patched} )
>>>
>>> and as a matter of facts this does the string replacement I'm interested
>>> in.
>>>
>>> Good, now I would like to use this to the project I'm really interested
>>> in which uses the ExternalProject_Add machinery. I added the patch step:
>>>
>>> <code>
>>>
>>> file (WRITE ${CMAKE_BINARY_DIR}/patch_script.cmake "
>>> file (STRINGS
>>> ${${proj}_SOURCE_DIR}/Wrappers/Python/ccpi/framework/TestData.py testdata
>>> NEWLINE_CONSUME)
>>> string(REPLACE \"sys.prefix\" \"os.environ[\\\'SIRF_INSTALL_PATH\\\']\"
>>> patched \${testdata})
>>> file( WRITE
>>> ${${proj}_SOURCE_DIR}/Wrappers/Python/ccpi/framework/TestData.py
>>> \${patched} ) ")
>>> ExternalProject_Add(
>>> ...
>>>
>>> PATCH_COMMAND ${CMAKE_COMMAND} -P ${CMAKE_BINARY_DIR}/patch_script.cmake
>>>
>>> ... )
>>>
>>> </code>
>>>
>>> Notice that I write the patch_script.cmake before the ExternalProject_Add
>>>
>>>
>>> Now, all of this WORKS. Or at least I get the patch_script.cmake file in
>>> the proper directoty, with the content I want. However, execution with
>>> cmake -P patch_script.cmake doesn't work as expected.
>>>
>>> I get
>>> CMake Error at build/patch_script.cmake:3 (string):
>>>   string sub-command REPLACE requires at least four arguments.
>>>
>>> Given that the patch_script.cmake has the same content of the standalone
>>> CMakeLists.txt above (without the first 2 lines), I don't know where things
>>> don't go well, except that I execute the script with cmake -P
>>>
>>> cmake version 3.15.2
>>>
>>> Thanks for any help.
>>>
>>> Edo
>>>
>>>
>>> --
>>> Edo
>>> I know you think you understand what you thought I said, but I'm not
>>> sure you realize that what you heard is not what I meant (prob. Alan
>>> Greenspan)
>>> :wq
>>> --
>>>
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>>
>
> --
> Edo
> I know you think you understand what you thought I said, but I'm not sure
> you realize that what you heard is not what I meant (prob. Alan Greenspan)
> :wq
>
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