Re: Checking breakage of backward compatibility

[Matt Rice]

--- Richard Frith-Macdonald
<address@hidden> wrote:

> 
> On 4 Oct 2006, at 12:46, David Ayers wrote:
> 
> > I'm almost indifferent on the subject.  But in
> practice I believe  
> > people
> > will unknowingly break binary compatibility and
> forget to bump the SO
> > name.  I think this is worse than forcing folks to
> recompile apps just
> > because the SO name bumped even though it didn't
> break binary
> > compatibility.... but like I said.  I wouldn't
> mind either way.
> 
> That worries me too ... but I think we *must* try to
> be strict about it.
> Is there any way we could devise an automated test
> for binary  
> compatibility breakage?
> 
> It seems to me that it should be possible to
> catalogue and check  
> externally available symbols (classes, functions,
> variables and  
> constants) using standard tools to examine the
> binary.  It should  
> also be possible to write a small program to inspect
> the objc runtime  
> to determine ivar layout and method signature
> changes.
> 
> Doing this would also be a useful exercise for
> finding out what  
> things are currently publicly exposed and should not
> be.
> 
> Tests could be run nightly on the current SVN trunk,
> providing  
> warnings telling us if we need to revert problematic
> changes made the  
> previous day.
> 


well i'm always in favor of a simple brute force
method
if one exists,

if we could take the testsuite and make it able to
store a 'snapshot' of precompiled binaries.. and the
test results which were written when they were
compiled/run, then test for differences between the
results and whatever version is currently installed...

also another question...

are we, or should we be tagging the testsuite whenever
we do a release of a library it tests for users who
may be having issues or want to test their
installation, or is it intended for development use only?

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