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[Improvement] - Add by default using optimum constructor selector to unify the choice of constructor for types #892
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If I understand correctly, select the ctor that has the most parameters that match the source properties. In an edge case, with a tie on the number, you are going with the first ctor based on alphanumeric sorting. Seems more logical then the logic of the person who created the ctors on the destination object.
select the ctor that has the most parameters that match the source properties.
This algorithm is use in 7.4.0, but it has one problem.
In this case, it won't select anything because nothing matches.Source { A } Destination { new (F) new (B,C) }That's why there should be two criteria = MaxMatched && MinUnmatched. (But in this interpretation it is much more difficult to calculate.)
In my opinion, it's safer to activate a constructor with a one parameter than with two. Because we can't actually know whether the constructor is capable of correctly handling the default value. 😂
*The letters are not for alphabetical order, but simply to show that these are parameters with different or matched names
So in the edge case example that you had
Destination { new (A,B) // MappingScore = -1; ParamCount = 1; <- select this max MappingScore new (A,C) // MappingScore = -1; ParamCount = 1; }either ctor could have been used.
The better question is if we have properties A and B in source and we have ctor A, ctor B, ctor A C, ctor B,C, what ctor would you use?
ctor A or ctor B, depending on which one was written first in the source code.
Apparently, this is how typeof(Test).GetConstructors() works.But I'm not sure maybe it sorts is alphabetically.
I was, of course, referring to
.GetConstructors().😑
You could, of course, add alphabetical sorting, but I don't really see the point.
It doesn't reduce the risk of non-operability, plus there's added extra costs of additional sorting.🤔Being nondeterministic within Mapster is fine. Don't add overhead.
Since the restriction of having a default constructor
new()for classes is no longer mandatory,and the constructor can using default values for the parameter type.
Optimality criterion(MappingScore) = maximum count of not mapped params. (MappingParam - CountParam)
If any constructors have the same MappingScore, select the one with more parameters.
Edge case: If any constructors have the same equal MappingScore and equal count of params select first.
Example:
Edge case: