This helps solving the problem encountered in #113553. The problem is that we
currently can't support link-drag-search for nodes which have a dynamic declaration.
With this patch, there is only a single `declare` function per node type, instead of
the separate `declare` and `declare_dynamic` functions. The new `declare` function
has access to the node and tree. However, both are allowed to be null. The final
node declaration has a flag for whether it depends on the node context or not.
Nodes that previously had a dynamic declaration should now create as much of
the declaration as possible that does not depend on the node. This allows code
like for link-drag-search to take those sockets into account even if the other
sockets are dynamic.
For node declarations that have dynamic types (e.g. Switch node), we can also
add extra information to the static node declaration, like the identifier of the socket
with the dynamic type. This is not part of this patch though.
I can think of two main alternatives to the approach implemented here:
* Define two separate functions for dynamic nodes. One that creates the "static
declaration" without node context, and on that creates the actual declaration with
node context.
* Have a single declare function that generates "build instructions" for the actual
node declaration. So instead of building the final declaration directly, one can for
example add a socket whose type depends on a specific rna path in the node.
The actual node declaration is then automatically generated based on the build
instructions. This becomes quite a bit more tricky with dynamic amounts of sockets
and introduces another indirection between declarations and what sockets the node
actually has.
I found the approach implemented in this patch to lead to the least amount of
boilerplate (doesn't require a seperate "build instructions" data structure) and code
duplication (socket properties are still only defined in one place). At the same time,
it offers more flexibility to how nodes can be dynamic.
Pull Request: https://projects.blender.org/blender/blender/pulls/113742
38813a7441