To clarify, that would have been Oracle's CDDL license at the time. Not trusting Oracle should be the default position of anyone with any sense in the industry.
> Apple abandoned the ZFS adoption process because of concerns over Sun's CDDL licence, not because of NIH syndrome.[0][1]
The CDDL is/was the license that is part of the public source distribution.
Given that Sun/Oracle owned the code, there was nothing stopping them from relicensing it to Apple under something different with a standalone contract that would have included things like support and escrow. From the zfs-dicuss post by Bonwick:
>> Apple can currently just take the ZFS CDDL code and incorporate it (like they did with DTrace), but it may be that they wanted a "private license" from Sun (with appropriate technical support and indemnification), and the two entities couldn't come to mutually agreeable terms.
> I cannot disclose details, but that is the essence of it.
CDDL was not the problem (as evidence by DTrace), but the terms of the 'private license' were as Apple wanted more than just basic functionality (which they could have gotten by importing the code).