Dictionary and Enumerable Mappings: Call EnsureCapacity if source count is known and target has a EnsureCapacity(int) method

[latonz]

If Mapperly generates a foreach / Add mapping the capacity of the target is increased as needed.
If the source/target count is known (type does have a Count/ Length property or Enumerable.TryGetNonEnumeratedCount() returns true) and the target type does have a Method EnsureCapacity(int), EnsureCapacity(source.Count + target.Count) can be called to ensure the target collection has a big enough capacity for all source objects plus the existing target objects and does not need to resize as mapped objects are added.

[Blackclaws]

This is already done via constructor arguments for dictionaries and lists I think. Calling EnsureCapacity there would be redundant

[latonz]

You are correct, if the target is created by Mapperly via new and the target type is a List or Dictionary. But if the target instance already exists, it is created via an object factory or is any type implementig IDictionary<,> or IList<> but is not Dictionary/List (eg. a custom List implementation), the capacity is not ensured.

[github-actions]

🎉 This issue has been resolved in version 2.8.0-next.2 🎉

The release is available on:

• GitHub release
• v2.8.0-next.2

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