[Qbs] Problems with QBS dependency detection

[Heiko Nardmann]

Hi together,

before going into details just a short question: am I the only one often
experiencing problems with dependency detection?


Now going into detail ...

*Situation*:

On our CI server we often see failing builds caused by linker problems
(MSVC 2015). /"Often"/ means around once a week - depending on the
changes; sometimes even more often ...

Today once again ... a colleague has added a 'const' qualifier to some
methods inside of a header file and of course also to the methods inside
the corresponding source file (C++). Let's call them 'changed.h' and
'changed.cpp'. Let's call one of those changed methods
'SignatureHasChanged()'; so it has been changed from

    void SignatureHasChanged()

to

    void SignatureHasChanged() const

*Problem seen*: the linker complains about not finding a method symbol.
By looking at the symbol I see that the linker looks for the old symbol
- that one w/o the 'const' qualifier. Huhh? Okay, who is the one using
that symbol? I found that source ... let's call it
'using_signaturehaschanged.cpp'.

Since the corresponding header and source files have been changed what
do I expect now to see in my build log? Of course a recompilation of
'using_signaturehaschanged.cpp'!

Hmm ... what do I *NOT* see? A recompilation of
'using_signaturehaschanged.cpp'!

Interesting enough this happens most of the times only on the CI slaves
- really rarely seen on the local machine (but it happens).

*So* ... am I the only one fighting with such problems???


Two things that might be relevant:

- the header file is a Q_OBJECT header, i.e. it is also processed by moc
- the source file is used twice inside the project: once within the main
product itself, once inside a component test

By sorting the relevant files I really see that
'using_signaturehaschanged.cpp.obj' is older than 'changed.h'. Which I
did not expect ...


/Kind regards,/

  Heiko
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