Currently the node tool node group and data-blocks referenced by it
may not be part of the active dependency graph. This means we
cannot retrieve their evaluated geometry when executing the operator.
Since operators almost always use the evaluated geometry of other
objects, and since geometry nodes is mostly set up to deal with
evaluated data-blocks currently, this must be fixed.
Instead, set up a temporary dependency graph and add the selected
objects and the data-blocks used by the node group. That graph is
evaluated to give simple access to evaluated data-blocks.
Unfortunately this will cause more work than necessary in a few ways:
1. Selected objects are reevaluated an extra time before execution.
2. All data-blocks referenced by the group are completely evaluated again.
3. The node group itself is reevaluated, which recreates the function graph.
These may or may not become bottlenecks in the future, but it's best to
keep it simple late in the release process. And between a completely
broken feature and a potentially slow feature, the choice is clear!
Pull Request: https://projects.blender.org/blender/blender/pulls/114293
2893dc8ab7