- Critical change that ensures reliablity and **should** have no bad side
effects, but when you see any, please report:
DICT, LIST, SET and Data List nodes (plus the DICT/LIST-taking STRING nodes)
now degrade gracefully when their data source is not connected (`None`) instead
of raising: read/query nodes return their natural "no data" result (the `get`
default, an empty list, `False`, `0`, `None`), and transform nodes behave as if
given an empty container.
- Add a "continue if not empty" flow-control node: it passes a value through
unchanged when it is non-empty, and blocks execution (via an execution blocker)
when the value is empty. It is list-aware (`INPUT_IS_LIST` / `OUTPUT_IS_LIST`),
so it is immune to ComfyUI's empty-input batching crash and passes data lists
through unchanged. By default the block is silent; an optional `message` can be
set to show a dialog. Use it before nodes that cannot handle an empty input
(e.g. a node receiving an empty Data List) to stop execution instead of failing.