feat: Exclude resource calculations from resource struct with `field?: false` option

[chazwatkins]

Improvements

• Add field? option to Ash.Resource.Calculation DSL
• Exclude field?: false calculations from Resource struct and direct loading, but still usable in expressions
• Add validation that returns Ash.Error.InvalidLoad error when loading a field?: false calculation directly
• Update calculations docs with explanation of field? option

We could probably do the same for aggregates once this is done.

#2242

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[chazwatkins]

ok, the validation is in and you now get an InvalidLoad error when you attempt to load a field?: false resource calculation.

[zachdaniel]

Just had a thought: we may actually have a bit of an issue here 😢

Specifically, AshGraphql and AshJsonApi will need to be updated to support this, by not allowing loads for these non-loadable calculations. We'll want PRs for those done before we release this.

[chazwatkins]

Just had a thought: we may actually have a bit of an issue here 😢

Specifically, AshGraphql and AshJsonApi will need to be updated to support this, by not allowing loads for these non-loadable calculations. We'll want PRs for those done before we release this.

No experience with those packages, but I'll take a look at them.

[chazwatkins]

Both api libraries only expose public?: true calculations. So, I made a small change to have public_calculations and public_calculation only return back field?: true calculations.

Do you see any cases where a field?: false calculation should be exposed outside the resource?

[zachdaniel]

Hmm...yes. It could be supported in filters exposed over GraphQL for example without being exposed as a field.