Re: [Vala] Rules for updating generated C files

[pancake <pancake youterm com>]

Same here

Can you open a bug for this?

I would prefer timestamps instead of checksums.

Another idea would be to make vala return 0 or 1 like 'test' do. So it  
would be integrated with Makefiles.

It would be also useful to make vala print out which files has changed:

$ valac --check a.vala b.vala...
a.vala

This method would be easily integrated with makefiles.

--pancake

On Jun 3, 2010, at 11:24 PM, Arc Riley <arcriley gmail com> wrote:

> Please do.  "This bug affects me too."
>
> On Thu, Jun 3, 2010 at 5:13 PM, Robert Powell <rob yorba org> wrote:
>
> > Hello,
> >
> > My understanding of the current rule for generating a C file from a  
> > vala
> > file is, if the contents of the C file has the same hash value, don't
> > rewrite the file.  When dealing with larger systems using  
> > libraries, this
> > rule may not be sufficient.
> >
> > I've attached an example program that illustrates the problem I  
> > describe
> > below.  To exhibit the problem:
> > 1. execute make
> > 2. execute ./main.  Note the output.
> > 3. comment out the variable comment_and_uncomment_me in file
> > BaseClass.vala.  Remember to save.
> > 4. execute make
> > 5. execute ./main.  Note the output is different and wrong.
> >
> > What is going on here
> > -------------------------------
> > We have a library BaseClass.vapi that is generated from  
> > BaseClass.vala.
> > This defines the class BaseClass.  We also have Derived.vala, which  
> > defines
> > a class that derives from BaseClass.
> >
> > If a member variable is added to BaseClass, BaseClass.vapi will  
> > change.
> > The
> > C file that is generated from Derived.vala will be identical, but  
> > it needs
> > to be recompiled because the base class has changed.  valac will not
> > regenerate Derived.c because it hasn't changed.
> >
> > I propose that if the C file (Derived.c in this instance) that is  
> > generated
> > has the same hash value as the existing C file BUT the  
> > corresponding vala
> > file (Derived.vala) imports anything from a vapi (BaseClass.vapi)  
> > that has
> > an earlier timestamp, the C file (Derived.c) should be touched.   
> > Does valac
> > have enough of this information to perform this check?
> >
> > For this simple system, it would be easy enough to update the  
> > makefile to
> > watch for this dependency.  For larger systems, however, I could  
> > see that
> > this could quickly get much more complex and error-prone.  I think  
> > that
> > with
> > the addition of this rule, it avoids this dependency problem.
> >
> > Is this a reasonable request?  Shall I file a bug?
> >
> > Thanks
> >
> > Rob
> >
> > _______________________________________________
> > vala-list mailing list
> > vala-list gnome org
> > http://mail.gnome.org/mailman/listinfo/vala-list
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