Component is blocking downstream flow even though it is on an inactive branch

(KNIME AP 4.7.1, Windows 10) As the topic name suggests, I am having a problem where a component on the inactive branch of an Empty Table Switch is blocking the flow. This should not occur.

I see that something similar to this has been reported before
eg

In that thread, it suggested that a bug fix would be implemented in release 4.7. I have just stumbled on something that looks very similar to this in 4.7.1 whereby a component is not fully deactivated in an inactive branch and causes it to block.

Note that it does not happen with all components.

Given that the above issue has already been identified, I wanted to check if this is the same issue (ie still awaiting a fix) before creating a minimal workflow to demonstrate the problem, which I can do but will take time.

In this case, I believe the issue is possibly to do with the use of flow variables that are created within the component and used in the configuration of the Component Output node. Under some circumstances (to be determined) the component will error as the variable is undefined. (It is undefined because the nodes within the component that that would have created it are inactive!). This causes the component to error on the component output node and block the downstream flow, even though the component is on the inactive branch and should not be executing.

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The fix for that reported issue in V4.7 under AP-19271 was specifically for the CASE Switch branch according to the patch notes, so I’d guess they did not include the Empty Table Switch node in that fix and you’re looking at a similar but new issue :wink:

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