GH-992..995: event model definitions — app model name, discovery manifest, ForAggregate, spec links

[jeremydmiller]

Closes #992, closes #993, closes #994, closes #995.

#992 Definitions join the application's model by default

• EventModelDefinition.Name is now string? and defaults to null, meaning the application's model. Overrides that return a string still compile.
• EventModelDiscovery.ApplicationModelName(services) is public, so other sources can reuse the rule. It resolves to:
  • JasperFxOptions.ServiceName, which Wolverine keeps in step with WolverineOptions.ServiceName, and which Marten already uses;
  • otherwise the entry assembly's name;
  • otherwise "EventModel".
• Each slice's Origin still names its own definition class (event-model://{ClassName}). For an instance with no name, Subject uses the class name too.
• Existing discovery tests that expected the class name as the model name have been updated.

#993 AOT-safe discovery of definitions

• New EventModelDiscoveryGenerator in JasperFx.SourceGenerator.
  • It lists every public, concrete, non-generic EventModelDefinition subclass that has a public constructor; definitions nested inside public types are included.
  • The list is a JasperFx.Generated.DiscoveredEventModels.DefinitionTypes manifest. [DynamicDependency(PublicConstructors)] keeps each listed constructor through trimming.
  • An empty manifest is still emitted whenever the compilation can see EventModelDefinition, so "generator ran, found nothing" is distinguishable from "generator never ran".
• New AddDiscoveredEventModels(assembly): reads the manifest and enumerates no types. Without a manifest it falls back to the reflective scan (the trim warning is suppressed, with a justification, as CommandFactory does).
• AddEventModelsFromAssembly also prefers the manifest now.

#994 ForAggregate / NoAggregate / DeciderModel

• ForAggregate: ForAggregate<T>() / ForAggregate(string) set a default aggregate.
  • The last call wins, and it applies only to Command slices opened after it that declare no aggregate of their own.
  • It never carries into another definition.
  • It also declares the aggregate on the model. Aggregate<T>() is unchanged.
• NoAggregate() and DeciderModel<T>() on a slice override the default. Calling NoAggregate() together with Against / StartsStream throws.
• The slice records why it has its aggregate:
  • EventModelSliceDescriptor.AggregateDeclaration { Default, Explicit, None, DeciderModel } and DeciderModel.
  • Two new roles, appended to EventModelRole, so they take part in the merge.
  • A default-applied aggregate is still a Declared claim: the code wins, and any difference becomes a hotspot.

#995 Specification links without strings

• Typed links: LinksToSpecification<TSpec>(nameof(TSpec.scenario)).
  • It uses SpecificationIdentity, a twin of Bobcat's current MarkerSpecNaming rule.
  • [BobcatFeature] is matched by attribute name, through CustomAttributeData.
  • The tests reuse Bobcat's own examples, e.g. apply_to_volunteer → apply to volunteer/volunteer application submitted.
  • Bobcat's code-first lane is gone. This matches the projected (xUnit/TUnit) rule that Bobcat uses today.
• The contract: SpecificationBindingDescriptor carries the spec identity, CommandType, and optionally Domain, Namespace, an explicit SliceName, and ResolvedTypes.
• The join: EventModelSpecifications.Link(model, manifest) is a pure function over an assembled model.
  • Specs join slices by command type. When several slices handle the same command, the spec's domain or namespace picks one.
  • An explicit slice name overrides the inference.
  • A join that is still ambiguous, or an explicit slice that doesn't exist, raises a model-level HotspotOrigin.UnresolvedSpecification hotspot instead of guessing.
• New rung EventModelProvenance.Specified:
  • Its wire value is 3, but it ranks between Declared and Derived.
  • Merge now compares rungs through Rank() / Outranks(), not the raw enum value.
  • A declared link the specs don't include loses and becomes a SourceDisagreement hotspot.
• Where the join runs (the issue's open question) is not settled in this PR. Only the contract and the join are here; the monitor or a --specs option are follow-ups.

Wire / downstream

• New wire members (all appended): Specified, UnresolvedSpecification, AggregateDeclaration, and the EventModelRole additions.
• event-model-vue types and enum pins are updated; type-check is clean and all 225 tests pass.
• CritterWatch needs to learn Specified and UnresolvedSpecification.
• JasperFx.SourceGenerator.Tests now references JasperFx.Events.

Tests

• EventTests: 1433 passing on both net9.0 and net10.0. That includes new ApplicationModelNameTests, DiscoveredEventModelsTests (a stand-in Assembly whose type enumeration throws), ForAggregateTests and SpecificationLinkTests, plus a wire round-trip extended to the new members.
• CoreTests: 656 passing on both net9.0 and net10.0.
• JasperFx.SourceGenerator.Tests: 29 passing, including 10 new manifest tests.
• The solution builds with 0 errors and no new trim warnings.

🤖 Generated with Claude Code

https://claude.ai/code/session_01J8KxC18Q51z5w4u6YARwe4