grant the same for those patents you own. Those CLAs do not require that you guarantee that your contribution is not violating any 3rd-party patents.
Nobody can require that, that'd be stupid - how one can guarantee nobody has patent to something? Even very expensive patent search doesn't give such guarantee - patent interpretations differ widely and there are submarine patents. Only thing one can reasonably guarantee is that the code is not covered by his own patents or he is granting license if it is and that he doesn't knowingly use somebody else's patented technology without having appropriate license.
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Stanislav Malyshev, Zend Software Architect
stas@zend.com http://www.zend.com/
(408)253-8829 MSN: stas@zend.com