The template models had no structural representation of OpenAPI polymorphic schemas (oneOf/anyOf/allOf). The workaround was a simplify-polymorphic-schemas patch that flattened everything into a single object, discarding discriminator info and making it impossible to generate correct language-level union/inheritance constructs (e.g. Jackson @JsonSubTypes).

Model changes

DiscriminatorModel (new type)

• PropertyName string -- the JSON property carrying the type tag
• Mapping map[string]CodeType -- discriminator value - fully resolved CodeType (name, qualified type, import path, etc.), giving templates access to all type metadata rather than a bare class name string

Model

• OneOf/AnyOf/AllOf []CodeType -- resolved variant/parent type references (replaces unused []Model)
• IsOneOf / IsAnyOf / IsAllOf bool -- flags for template branching
• Discriminator *DiscriminatorModel -- populated when a discriminator is present

Property

• Added Required, ReadOnly, WriteOnly bool from the source schema

BuildComponentModels rewrite

Each schema now follows a dedicated branch instead of collapsing into a flat merge:

• oneOf / anyOf -- each *SchemaProxy resolved to a CodeType; discriminator mapping resolved to CodeType values via the component schema registry
• allOf -- referenced sub-schemas - AllOf []CodeType parents; inline sub-schemas - properties merged directly (dedup-aware, inheriting required from both the root schema and the inline sub-schema)
• object / array / fallback -- unchanged, only reached when no polymorphic case applies

Extracted helpers: buildModelProperties (sets Required/ReadOnly/WriteOnly, handles deduplication across allOf merges) and buildDiscriminatorModel (resolves $ref mapping entries to full CodeType values).

Default patches

Removed simplify-polymorphic-schemas from DefaultCodeGenerationPatches -- it is no longer needed as a default; it remains available for opt-in use.

Example -- discriminator-based oneOf

Produces a PetDto model with:

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