[Boost-build] Why to repeat library dependency ?

Subject: [Boost-build] Why to repeat library dependency ?
From: Christophe B (boost_at_[hidden])
Date: 2015-03-28 07:12:55

Hi,

I am using boost.build for my projects (currently, gcc-4.8 under ubuntu)

According to the documentation
(http://www.boost.org/build/doc/html/bbv2/tutorial/linkage.html), it is
not necessary to repeat library dependency at higher level to allow
linkage. If A depends on B and B depends on C, it is not required to
mention the dependency of A to C.

#Very simplified dependency scheme for clarity
unit-test A : B ;
lib B : C ;

Unfortunately, I do not observer this behaviour and I get a linker error
claiming that symbols from C are missing.
Explicitly adding a dependency to C on A solved my issue:

unit-test A : B C ;
lib B : C ;

This seems to contradict the documentation.
Can it be any reason for requiring to repeat a dependency on higher level ?

Thanx in advance,

Christophe