[Scons-users] Batch building includes unchanged targets

[Dirk Bächle]

On 25.10.2013 04:40, Sean Houghton wrote:

> I discovered a bug in my batch builder caused by a missing file flush 

> which resulted in constant rebuilds.  However, the problem is now that 

> any time a single input changes the entire set of sources is passed to 

> the batch builder, regardless of change state.

>

Thanks for the example...

You're using the batch functionality, which basically means that you 
give SCons a black box and say: "Here is my batch builder. It gets N 
input files, and has M outputs (=targets)."

With this, SCons will register an NxM dependency for the DAG where each 
of the M targets depends on all N sources. This is what you're currently 
seeing, and I don't think it's a bug...it's what batch building should do.

If you don't want this behaviour, don't use the batch build but process 
your files in single calls (single_source=True). This will also give you 
less implicit dependencies overall, so your build usually performs 
better regarding speed and memory.

Regards,

Dirk