[Scons-users] Scons Implicity Dependency not found issue

[Hua Yanghao]

On Thu, Oct 25, 2018 at 10:08 PM Jason Kenny <dragon512 at live.com> wrote:
>
> Hi,
>
> I would recommend myself that you use duplicate=0 then. The point for duplicate=1 as default is that there are some tools that don't deal with files input output location and to help avoid possible issues if you have a large build and you might have modified a file while the build was going on ( given you tell SCons to make copies instead of hardlinks... ie this is the --duplicate option). There are a few issues with this however:
>
> 1) windows will make copies as SCons does not understand symlink or hard links on this platform with out some extension added to it
> 2) takes extra times as one has to create items
> 3) when it is making copies I have had issues I cannot explain yet ( ie not looked in to enough) where scons does not update the files in the variantdir correctly making bad builds. ( I think that is what you are seeing)
>
> For large build the time save with duplicate=0 is a big deal, as well as the disk savings given the hard-soft-copy options is not working correctly
>
> Bill -- just a guess but I think the issue when copy is being used is that SCons nodes understand the variant and srcnode exists, but has no check, or depends logic to say variant version depends on the srcnode version so there are cases in which a depends on a variant node does mean that the srcnode "copy" update is not seen. So for example the scanner does gets a file and tests that it exists, but since the header does not have any builder the logic to understand that the it should update based on the value of srcnode() version is skipped.
>
> -Jason

Thanks Jason. I am seriously considering doing so now ...