RFC: Relative source file paths

From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-12-24 04:54:22

Hi,
recently, we had a couple of problems caused by using relative file paths, and 
I'd like to discuss what to do.

Let's use the case from Cédric. Simplified version is:

exe a : a.cpp dir1/qt_file.h ;
exe b : a.cpp dir2/qt_file.h ;

Both exes have the same source cpp file but different *.h files -- which are 
processed by Qt tools. V2 currently strips directory name from all targets, 
so it tries to

- create "bin/mvsc/debug/moc_qt_file.cpp" from dir1/qt_file.h
- create "bin/msvc/debug/moc_qt_file.cpp" from dir2/qt_file.h

There are two solutions that I see:

1. Rewrite the code like:
      
lib aux : a.cpp 
exe a : aux dir1/qt_file.h : <location-prefix>a ;
exe b : aux dir2/qt_file.h : <location-prefix>b ;

This way, two version of moc_qt_file.cpp will be generated to different
places. 

2. Rewrite the code like:

obj a_moc : dir1/qt_file.h : <library>/qt//qt ;
exe a : a.cpp a_moc ;
obj b_moc : dir2/qt_file.h : <library>/qt//qt ;
exe b : a.cpp b_moc ;

Explicitly changing name for the problematic files.

3. Generally change V2 so that directory part of source is preserved. This
will generate targets:
"bin/msvc/debug/dir1/moc_qt_file.cpp" and
"bin/msvc/debug/dir2/moc_qt_file.cpp". No problems.

However, there are some additional questions:

- What if source has absolute file name?
- What if source is "../../include/qt_file.h"?

We can ignore directory names in those cases (i.e. use the current 
behaviour) but that would be a bit inconsistent.

Any opinions?

- Volodya