[Scons-users] 回复： "Defer to SCons to build build\__cpp_path.txt"

Thu Apr 28 08:16:05 EDT 2022

Hello Daniel Moody,
Attached is the build.ninja file generated by executing the scons command twice, there are indeed differences.
Below I extract the first difference:
<<< first
build $
    D$:\work\current\master\knd\libs\CncSys\K2000PRJ\DataItems\DataItemApiwInputDialogUi.autogen.h $
    D$:\work\current\master\knd\libs\CncSys\K2000PRJ\DataItems\DataItemApiwInputDialogUi.autogen.cpp: $
    GENERATED_CMD | $
    D$:\work\current\master\knd\libs\CncSys\K2000PRJ\DataItems\DataItemApiwInputDialog_Ui.py

>>>

<<< second
build $
    D$:\work\current\master\knd\libs\CncSys\K2000PRJ\DataItems\DataItemApiwInputDialogUi.autogen.cpp $
    D$:\work\current\master\knd\libs\CncSys\K2000PRJ\DataItems\DataItemApiwInputDialogUi.autogen.h: $
    GENERATED_CMD | $
    D$:\work\current\master\knd\libs\CncSys\K2000PRJ\DataItems\DataItemApiwInputDialog_Ui.py

>>>

You can see that "autogen.cpp" and "autogen.h" are in different order.

The relevant generation scripts for these two files(cppFile, hFile) are as follows:
<<<
UiPyFiles = glob.glob(cwd + "/**/*_Ui.py", recursive=True)
    for f in UiPyFiles:
        (filePath, fileName) = os.path.split(f)
        pyModuleName = fileName[:-6]
        cppFile = f[:-6] + "Ui.autogen.cpp"
        hFile = cppFile[:-4] + ".h"
        Env.Command(
            [cppFile, hFile],
            [f],
            [
                '''@cd ${SOURCE.dir} && @%s -c "import sys;sys.path.insert(0, '%s');sys.path.insert(0, '%s');from %s import %s; %s.render();"''' % (sys.executable, os.path.join(rtconfig.KND_ROOT, "tools", "python").replace("\\", "/"), filePath.replace("\\", "/"), fileName[:-3], pyModuleName, pyModuleName),
                "@echo Create file: %s, %s" % (cppFile, hFile)
            ]
        )
        path = os.path.relpath(cppFile, cwd)
        obj = Env.Object(target = path[:-4] + ".o", source = cppFile)
        autogenObjs += obj

>>>

You can see that the target order in env.Command is consistent with the order in the second build.ninja.

------------------ 原始邮件 ------------------
发件人:                                                                                                                        "Daniel Moody"                                                                                    <dmoody256 at gmail.com>;
发送时间: 2022年4月27日(星期三) 晚上11:36
收件人: "liruncong2018"<liruncong2018 at qq.com>;"SCons users mailing list"<scons-users at scons.org>;

主题: Re: [Scons-users] "Defer to SCons to build build\__cpp_path.txt"

Hello Liruncong,

I could not reproduce your case in a simple test. I think your build is creating some differences each time scons is run. The ninja tool will regenerate the ninja file if there are any differences from the previous ninja file, for example even if the command line options for some compilation are the same but in a different order. In that case all things which ninja will defer to scons to build, must be rebuilt. SCons however may determine for those items that they do not need to be rebuilt because the inputs (the CPPPATH string) have not changed.

I pushed an update to the ninja_integration_branch which prints an additional message if scons decided to regenerate the file. If it decides to regenerate the build.ninja file you should see a message like:

Generated new build.ninja!

If scons decided not to regenerate the ninja file because there were no changes you should see:

No updates detected,  build.ninja  not regenerated.

If you see the ninja file is being regenerated each time, please make a copy of the build.ninja file, then run again and compare the original copy to the newly generated ninja file. You can send me both copies so I can see if for some reason scons is causing the unexpected regeneration.

On Wed, Apr 27, 2022 at 7:16 AM liruncong2018 <liruncong2018 at qq.com> wrote:

Hi,
After successful compilation, select a file and add a blank line, then execute the following two commands in sequence:
1) run_ninja_env.bat -d explain build\__cpp_path.txt
2) scons -j%NUMBER_OF_PROCESSORS% --experimental=ninja
The attachment is the execution result of the above two commands.
The following output from the log record should be removed:
···
[2/2518] Defer to SCons to build build\__link_objects.txt [2K
[3/2518] Defer to SCons to build build\__exe_cpp_path.txt [2K
[4/2518] Defer to SCons to build build\__cpp_path.txt [2K
[5/2518] Defer to SCons to build build\__define_options.txt [2K

···

From the file time point of view, the 4 txt files have not been recompiled, so there should be no output information.

------------------ 原始邮件 ------------------
发件人:                                                                                                                        "Daniel Moody"                                                                                    <dmoody256 at gmail.com>;
发送时间: 2022年4月27日(星期三) 凌晨2:51
收件人: "SCons users mailing list"<scons-users at scons.org>;
抄送: "liruncong2018"<liruncong2018 at qq.com>;
主题: Re: [Scons-users] "Defer to SCons to build build\__cpp_path.txt"

It depends on the specific files in question and their dependencies. Looking at the most recent build.ninja you sent, these files only depend on the scons build (they are from the Textfile builder, so then in the scons build, the only dependency is the source string, which is generated from CPPPATH in the SConscripts files).

I would like to know why ninja decided to rebuild these files if they are already built. After this issue is occurring, then run this command

run_ninja_env.bat -d explain build\__cpp_path.txt

And ninja should say why it is attempting to rebuild the file. Please send me the output as well.

On Tue, Apr 26, 2022, 8:18 AM liruncong2018 via Scons-users <scons-users at scons.org> wrote:

Hi,When there are file errors that are not corrected, the following lines always appear when compiling, but the file time has not changed, indicating that the file has not been regenerated.Is it possible not to display this information if the file is not regenerated? Otherwise, users will think these files have been updated.···[2/2518] Defer to SCons to build build\__cpp_path.txt [2K[3/2518] Defer to SCons to build build\__link_objects.txt [2K[4/2518] Defer to SCons to build build\__define_options.txt [2K···

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