Auto-wire cases inside loops when adding shift registers

[jhibma]

Suppose you have a while loop containing a case state machine with several cases.  Then later you decide to add a shift register.  It's very time consuming to wire every case when you might need to alter the contents of the shift register in a single case.  So when adding the shift register and the user connects the SR wires to one case, auto connect all the other cases internally.

[fefepeto_kb]

For the case structure, on the output tunnel there is an option in the right click menu (context menu) called Linked Input Tunnel. If you already wired one of the cases then you can simply choose the Create & Wire Unwired Cases menu item and it will automatically wire all the cases, without selecting the input tunnel.

If you first created the case where you want to alter the content of the wire and use the Create & Wire Unwired Cases menu item there, then you also have to select the input tunnel.

In my opinion, and also based on some best practice guides I read, this tool shall only be used to create the initial state of the case structure wires, then turned off. Otherwise it will automatically wire the all cases that are added after this auto-wiring has been created, which might lead to bugs, since there is no indication of a missing input for the output tunnel. To make sure the auto wiring does not happen afterwards we usually also use the Clear menu item, this way all the actual cases are wired, and the issues related to maintenance are also solved.

I know this is a few more clicks then fully automating the wiring but this is also the preferred behavior of the development environment by many developers.

[raphschru]

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@fefepeto_kb wrote:

this tool shall only be used to create the initial state of the case structure wires, then turned off. Otherwise it will automatically wire the all cases that are added after this auto-wiring has been created, which might lead to bugs, since there is no indication of a missing input for the output tunnel.

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In my opinion, the auto-wiring of the newly added cases is the best advantage of using the "Create & Wire Unwired Cases" feature. It saves wiring for future development and it indicates to the future developer which wires must pass through if their data is untouched. I always consider maintaining the value (so having a wire) to be the default (no-op) behavior. It is particularly useful for state machines.

[fefepeto_kb]

The best practices were derived from the experience. We have been working with developers of various experience and having the cases auto-wired resulted in more review feedback/bug, therefore the recommendation has become not to rely on this feature.

I'm not saying that it isn't comfortable, but the experience showed it's more time consuming.

Similarly to car driving, the more driving aids are present the less involvement for the driver. This results in decreased attention, because of the boredom. Although, in this case, the effects are more pronounced on shorter trip more, since a long trip with a lot of involvement can be exhaustive.

I think, this might also apply to this exact problem, if the change in code is small, the developer might overlook some of the wires, while doing a lengthy development of the code is more likely to prove the advantage of this feature. That might have played a factor in recommending this to be on when designing the code, and to be turned off for maintenance tasks, which are usually a short interaction with the code.