[Brananarchy]

IANAL and all that...

If it's truly accidental (as in a rogue employee or a script that f'd up), they probably have a legal basis to break the contract/license terms and retract it. Just as stores are not required to honor misprinted price tags. There will likely be a court case if someone believes they legitimately received a GPL-licensed version of the code and wants to use that code in another project (or pass it on to others). Like I said, I think Adobe has a good case to win that here.

If it's "accidental", and they're just trying to walk it back, there would definitely be a court case. Whether they'd win or lose would be very up in the air, and probably depend on the jurisdiction's friendliness to businesses.

[MrJohz]

And if it was completely deliberate but they simply regretted the decision, then they would not be able to revoke the licenses they'd already given out, i.e. that version would be essentially out in the wild and under GPL forever. But future versions could be closed-source again, assuming Adobe retained all the copyright to their code.