Why not contribute? (to GCC)

Mark Mielke mark@mark.mielke.cc
Mon Apr 26 09:41:00 GMT 2010

On 04/26/2010 12:31 AM, Ian Lance Taylor wrote:
> Mark Mielke<mark@mark.mielke.cc>  writes:
>> Wouldn't contributing a patch to be read by the person who will be
>> solving the problem, but without transferring of rights, introduce
>> risk or liability for the FSF and GCC?
>> I thought "clean room implementation" implies not seeing how somebody
>> else did it first, as the "clean" part is tainted after somebody
>> examines the patch?
> Clean room implementation techniques are not required to avoid
> copyright violations.  Copyright only covers the expression of an
> idea; it does not cover the idea itself.  Expressing the same idea in
> different code is not a copyright violation.  Even independent
> identical expressions are not copyright violations if they are truly
> independent.  And if there is only one possible way to express an
> idea, then copyright does not apply at all, as there is no creative
> aspect to the work.

They aren't truly independent if you use the patch as a model to work 
from. Demonstrating to a judge that your work is unique might be a lot 
more difficult if you confess to reading the original before writing the 

What are clean room implementations for if not for avoiding copyright 
violation? At my company, we took things seriously to the point of 
dividing the GPL designers from the non-GPL designers to prevent code 
fragments from being leaked to one side or the other, even if just a 
faint memory that ends up resulting in code that looks just about 
exactly like the original, even if the author cannot identify what the 
original was.


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