Re: not rebuilding out-of-date derived^2 objects

[Alan Grow]

> From: Malcolm Blaney <address@hidden>
> To: Alan Grow <address@hidden>
> CC: address@hidden
> Subject: Re: not rebuilding out-of-date derived^2 objects
> Date: Mon, 19 Apr 2004 11:19:39 +0930
>
> Alan Grow wrote:
> > Hi,
> >
> >  Cons 2.3.0 isn't rebuilding "derived derived objects" correctly for me. 
> > I've attached a tarball you can use to reproduce the behavior, but here's 
> > what's going on...
> >
> >  I am building libfoo.a from foo.o, which is built from foo.h and foo.cpp 
> > in turn. The first time I cons, everything is rebuilt. Then if I add a new 
> > function (say) to foo.h and cons again. This time foo.o is rebuilt but 
> > libfoo.a is not, even though foo.o's contents have changed.
> >
> >  I have left SourceSignature and SIGNATURE alone so they should be 
> > defaulting to 'build', but it doesn't seem to matter. Also I am using two 
> > Conscript files, one for the object file and one for the lib, because this 
> > mimics the situation I first encountered the problem in. Anyway untar and 
> > have a look for yourself.
>
> Please don't attatch a tar, just include the Construct & Conscript in your 
> email, it's not that much code...

Okay I just wanted you to be able to quickly reproduce my problem. 
Personally I would have been irritated, and wouldn't bother responding, if 
someone hadn't provided this convenience for me.

> >  Am I using cons in a way that wasn't intended?
>
> Yes, the Program and Library methods are designed to do what you're trying 
> to do with Command. You're missing the dependency between foo.o and 
> libfoo.a, which you should see when running cons -d.

I am well aware of the Program and Library methods. This is just an example 
that reproduces the problem, in reality I am building something totally 
different--an nsis installer that includes csharp assemblies and a lot of 
other garbage.

After modifying foo.h:

cons -d

Target lib/libfoo.a: src/foo.o src/foo.o
Checking lib/libfoo.a
 Checking src/foo.o
   Checking src/foo.cpp
   Checking src/foo.h
   Checking /usr/bin/g++
 Rebuilding src/foo.o: out of date.
/usr/bin/g++ -Isrc -o src/foo.o -c src/foo.cpp
 Checking /usr/bin/ar
Target src/foo.o: src/foo.cpp src/foo.h

This shows that libfoo.a is indeed dependent on foo.o. You can add an 
explicit $env->Depends to lib/Conscript if you don't believe me.

> Have a look at the examples in the docco, and use/put the compiler commands 
> in the env object in the Construct file.
>
> Malcolm.

Why would I put all my compiler commands in Construct? My build is large and 
hierarchical, and has many points of entry.

I still think something is amiss here.

-Alan

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