fix: default predicate value on construction

[domire8]

Description

• Predicates are still published periodically in python components #158

The original problem of the parent issue is solved in cc85c64. However, as explained there is another problem which is that the initialization of the previous_value in the Predicate class is not ideal and should be revised.

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Estimated Time of Review: 10 minutes
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Checklist before merging:

• Confirm that the relevant changelog(s) are up-to-date in case of any user-facing changes

[domire8]

We could also revert 3ec1d71, keep it for a future 6.0.0 and fix it non-breaking for now and make a 5.0.1

[eeberhard]

I would like to see this as a patch 5.0.1, since it implements the intended behavior following from the already breaking change in 5.0.0.

It is not a breaking API nor ABI change for all intended use-cases, because:

• the changed property is private to the class
• it’s a header-only class, so there is less risk of a translation unit being out of sync with the header file
• the class is used internally by modulo and is not intended to be accessed directly by any public users
• the patch comes shortly after the major update

If a user did in fact use the Predicate class in some project downstream, then there are certain scenarios under which 5.0.0 and 5.0.1 might be incompatible. With the patch comes so shortly after the main breaking change, I see very little room for confusion or issues. We can still delete the 5.0.0 release as necessary if we want to be extra safe about avoiding confusion.

[domire8]

This is ready then 👍