[Scons-users] How to restart a scanner if it cannot provide all dependencies.

[Michael Hasling]

Hi Dirk,

Thanks for the description of the scanning process. It largely matched what I'd figured out by experimentation, which is encouraging!

> There is no way to say "Uhh, I found some dependencies...but some more
> may follow later, please hang on.". If that would be the case, how and
> under which condition(s) exactly should the build stop...meaning: when
> exactly should the Taskmaster decide that all dependencies are found?

I think this is the essence of the problem I had. SCons does not support this, and there's no API, or special return value that a scanner can use to reset the 'needs scanning' state of the target node, or indicate that the scan was incomplete.

I wonder if this capability could be considered as an enhancement? (but maybe you think the use case I have is a little too esoteric?)

Meanwhile I have spent a little time adapting my scanner to retain some state in the builder environment, and use this on subsequent hierarchical invocations to intercept scans of subscripts and redo them from the top-level source script so that the Tcl interpreter context is correct. It seems to be achieving what I need, so I guess I have a workaround.

Thanks for the responses.

Regards,
Mike