Fix Process to keep step sequence after removing step

[Richtermeister]

Currently removing a step from the process leaves gaps in the step sequence and a process is considered closed at the breakpoint, even though there are more steps thereafter. This commmit ensures that proper index sequence is maintained throughout step removal/additions.

[pjedrzejewski]

Actually I had this problem too... :) Thank you Daniel!

[Richtermeister]

Welcome! I'm thinking over time I'd like to make the steps a bit more flexible as well. Right now they are very linear, but in a checkout process I think people need to be able to jump around and for returning visitors I would like to drop them off at the highest available step.. stuff like that.
Ideally steps should also be able to determine whether they are accessible on their own.

[pjedrzejewski]

You can already jump between steps, so non-linear processes are possible, where some steps are skipped or you have several paths. But yes, there is a limitation in regard to which step user can "get back". Your idea about step being able to determine whether it is accessible is very cool. Best scenario is where we have current behavior as default and allowing to customize this like you said.

[Richtermeister]

IIRC once you step back to a previous step the history is rolled back and you have to step forward sequentially again to get back to where you were. So, after going from the Finalize step to the address step, you can't go back to finalize directly. If my memory serves right.. For the current Sylius structure that is actually a good thing since changing the address would have to cause tax/shipping to be recalculated, but just visiting a step is currently enough to kill the history. And yes, defaulting to linear is fine.