ObservableEventsGenerator (contributors)

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This page describes generator repository layout for ObservableEventsGenerator. It does not change the consumer API documented in Observable events.

No consumer impact

The generator was refactored into partial files and unused pre–0.6.0 flat wrapper codegen was removed. Generated output and public extension methods are unchanged from 0.6.1.

Where the code lives

Shared sources: MvvmAIO.R3.SourceGenerators/MvvmAIO.R3.SourceGenerators/ (listed in MvvmAIO.R3.SourceGenerators.projitems; all Roslyn* projects import it).

ObservableEventsGenerator is a public sealed partial class with [Generator] on the root file only.

File map

File	Role
ObservableEventsGenerator.cs	Initialize, post-init bootstrap, RegisterSourceOutput orchestration
ObservableEvents/ObservableEventsConstants.cs	Entry method names, GeneratedNamespace, QualifiedType()
ObservableEvents/ObservableEventsEntryKind.cs	FromEvents, routed, attached kinds
ObservableEvents/ObservableEventsModels.cs	ObservableEventTargetSets, EventInterfaceDescriptor, constraint targets
ObservableEventsGenerator.Discovery.cs	Syntax filtering, CollectObservableEventTargets
ObservableEventsGenerator.InterfacePipeline.cs	EmitInterfaceBasedSources, hierarchy, name collisions
ObservableEventsGenerator.InterfaceEmission.cs	Interface / *Impl / extension emission
ObservableEventsGenerator.GenericConstraints.cs	where T : A, B combined interfaces
ObservableEventsGenerator.RoutedDetection.cs	WPF / Avalonia routed CLR detection
ObservableEventsGenerator.AttachedRouted.cs	Avalonia attached routed extensions
ObservableEventsGenerator.EventProperties.cs	Event Observable properties, delegate checks
ObservableEventsGenerator.Helpers.cs	Identifiers, constraint clauses, diagnostics helpers
ObservableEventsSyntaxFactory.cs	Roslyn syntax only (no orchestration)

When you add a .cs file, register it in alphabetical order in MvvmAIO.R3.SourceGenerators.projitems.

Runtime pipeline

flowchart TD
  init[Initialize]
  discover[Discovery: CollectObservableEventTargets]
  iface[InterfacePipeline: EmitInterfaceBasedSources]
  emit[InterfaceEmission + GenericConstraints]
  attached[AttachedRouted per target]
  init --> discover
  discover --> iface
  iface --> emit
  discover --> attached

1. Post-init — bootstrap extensions + NullEvents (GeneratorBootstrapSyntaxFactory).
2. Discovery — record types from FromEvents(), routed entries, generic constraints, attached routed.
3. Interface pipeline — build EventInterfaceDescriptor tree → EventInterfaces.{kind}.g.cs + {Type}.{kind}.g.cs.
4. Attached routed — separate path; returns Observable<T> (not the interface model).

Static ObservableEventsStatics / OBS_* discovery exists but generation is disabled (StaticObservableEventsGenerationEnabled = false).

Removed internal paths

Do not reintroduce without a design discussion:

• v0.4.x flat wrapper classes (GenerateObservableSourceForType, CreateWrapperClass, old CreateExtensionsClass chain).

The only instance and routed paths are the interface pipeline above.

Further reading (generator repo)

Document	Contents
AGENTS.md	Conventions, CI, diagnostics, full source map
docs/README.md	In-repo developer doc index
design-interface-based-event-generation.md	Interface hierarchy algorithm (中文), §11 source layout

Related pages

• Architecture overview
• Observable events — consumer guide
• Contributing