Re: [Boost-build] [bjam] Incremental builds and deleted/movedheader dependencies

From: Johan Nilsson (r.johan.nilsson_at_[hidden])
Date: 2007-05-04 01:38:44

David Abrahams wrote:
> on Tue Apr 24 2007, "Johan Nilsson" <r.johan.nilsson-AT-gmail.com>
> wrote:
>
>> This is probably not possible (or perhaps not even desirable to
>> resolve), but I just need to get some comments on this issue:
>>
>> 1. Suppose that file a.cpp depends on a.hpp and a_util.hpp (included
>> from a.cpp).
>> 2. Suppose that running bjam in the project folder happily produces
>> the exe "a".
>> 3. Then, I delete a_util.hpp and rerun bjam (without the -a flag).
>> 4. Nothing happens, as the change isn't detected.
>>
>> This can't be the desired result.  Intuitively, I'd expect an
>> attempt for recompilation of a.cpp with a failure due to the missing
>> header.
>
> I'm inclined to agree.

Well, that's at least one more person. Good.

>
>> I realize why the recompilation shouldn't happen in the general
>> case, as this would otherwise cause constant rebuilds whenever bjam
>> couldn't locate an included header file.
>
> Hm.  I'm not sure that's a big deal except for system headers.

Shouldn't be. Still, how would one distinguish between such headers and 
others? Perhaps some project property could be used to specify an include 
regex pattern for the headers that will cause a recompilation of dependent 
source if they are not found, e.g. "^<myproj/".

/ Johan