Deterministic UBL Base emit (records + interfaces, StripEmbedded)

name: UBL Base strip emit overview: Add a deterministic Roslyn emit profile that generates InvoiceBase / CreditNoteBase / ReminderBase as records + interfaces (plus a shared billing spine interface), rewriting BinaryObject embeddings to metadata-only refs so large attachments cannot inflate heap. todos:

• id: codegen-base-profile

content: StripEmbeddedBaseProfile + BinaryObjectRef + IBillingDocumentBase; EmitOptions; unit tests ≥85% status: completed

• id: xsd-host-ubl-base

content: RoslynXsdCodeGenerator.GenerateBase + XsdGen ubl-base → Ubl.Lean/Generated status: completed

• id: mappers-tests

content: Wire↔Base mappers for Invoice/CreditNote/Reminder; no-byte[] + heap tests; retire hand LeanModels status: completed

• id: publish-docs

content: Publish CodeGen.Xsd + Ubl.Lean; README/canvas pointers; nuget-only check status: completed isProject: false

Derived from ubl-type-hierarchies and current Wire/Lean stack. Extends `Novolis.CodeGen.Xsd` and dogfoods via `novolis-xsd`.

Locked decisions

• Shape: positional/init records + matching `I{Name}Base` interfaces (not XmlSerializer Wire classes).
• Names: InvoiceBase / CreditNoteBase / ReminderBase (and line/CAC analogues as *Base), plus shared spine IBillingDocumentBase.
• Package: commit generated sources under `Novolis.Xsd.Ubl.Lean` in Generated/ (replace hand-thin InvoiceLean surface over time; keep mappers as Wire↔Base).
• StripEmbedded: BinaryFacet / byte[] Value omitted; keep metadata attributes (mimeCode, filename, uri, format, encodingCode, characterSetCode) on a generated BinaryObjectRef record. ExternalReference stays as-is (already non-byte).
• Scope v1: document closures of Invoice, CreditNote, Reminder only (SchemaGraphScope + three roots).
• Determinism: SchemaGraph ordered type ids; stable property order; one file per type; no timestamps in output.

flowchart TB
  xsd[UBL XSD] --> graph[SchemaGraph]
  graph --> scope[Filter Invoice CreditNote Reminder closure]
  scope --> profile[StripEmbeddedBaseProfile]
  profile --> binRef[BinaryObjectRef metadata only]
  profile --> spine[IBillingDocumentBase]
  profile --> docs["InvoiceBase / CreditNoteBase / ReminderBase"]
  profile --> ifaces["IInvoiceBase / ..."]
  docs --> leanPkg[Novolis.Xsd.Ubl.Lean Generated]
  wire[Wire InvoiceType] --> mapper[ToBase StripEmbedded]
  mapper --> docs

CodeGen (`novolis-codegen`)

New emit profile

Add `StripEmbeddedBaseProfile` implementing IEmitProfile:

• For each included complex type FooType → emit:
• public interface IFooBase { ... }
• public sealed record FooBase(...) : IFooBase; (or FooBase without Type suffix for document roots: `InvoiceBase` from InvoiceType)
• Naming rule (deterministic):
• Document roots (IsDocumentRoot): strip trailing Type → InvoiceBase, interface IInvoiceBase
• Other complex: {CSharpName} with Type→Base (InvoiceLineType → InvoiceLineBase)
• Collections: IReadOnlyList<TBase> (not Collection<>)
• Simple CBC wrappers with non-binary Value: collapse to CLR scalar or keep thin *Base with Value only — collapse to CLR for identifier/amount/code/date (smaller graphs; matches current Lean intent). Keep nested CAC as Base records.
• Binary rewrite (core OOM guard):
• When particle/attr type has BinaryFacet != None or resolves to byte[]: emit property type BinaryObjectRef? instead of nested binary type / byte[]
• Do not emit EmbeddedDocumentBinaryObjectType / UDT BinaryObjectType as full types
• Emit single shared:

public sealed record BinaryObjectRef(
    string? MimeCode,
    string? Filename,
    string? Uri,
    string? Format,
    string? EncodingCode,
    string? CharacterSetCode);

• Skip emitting any type whose only content would be byte[] Value after strip (no orphan empty types).

Shared billing spine

After emitting the three document Bases, emit `IBillingDocumentBase` listing the exact triple-intersection property set (35 props from hierarchy analysis), using Base/scalar types. Each of IInvoiceBase, ICreditNoteBase, IReminderBase extends IBillingDocumentBase. Document-specific props remain only on the concrete iface/record.

Role analogues stay document-specific (InvoiceTypeCode vs CreditNoteTypeCode vs ReminderTypeCode) — not forced onto the spine.

EmitOptions additions

Extend `EmitOptions`:

• StripEmbeddedPolicy = MetadataOnly (default for this profile)
• BillingSpineInterfaceName = "IBillingDocumentBase"
• Reuse IncludeTypeIds / root namespace / one-file-per-type

Tests (`Novolis.CodeGen.Unit/Xsd/`)

Coverage: keep CodeGen.Xsd line ≥ 85%.

novolis-xsd host

Generator API

Extend `XsdGenerationOptions` + thin RoslynXsdCodeGenerator.GenerateBase(...):

• Profile = Base (StripEmbedded)
• ScopeLocalNames = { Invoice, CreditNote, Reminder }
• Output: src/Novolis.Xsd.Ubl.Lean/Generated

Tool

`tools/XsdGen`:

ubl-base   # regenerate Lean/Generated Bases (roslyn StripEmbedded)

Wire existing ubl-lean to call the same path (or alias).

Mappers (hand + tests)

Replace stub mappers in `Mappers.cs`:

• InvoiceBaseMapper.ToBase(InvoiceType) / FromBase (FromBase does not restore bytes)
• Same for CreditNote + Reminder
• Strip path: DocumentReference.Attachment.EmbeddedDocumentBinaryObject → BinaryObjectRef from attrs; Value ignored
• Also strip Signature.DigitalSignatureAttachment embeddings in closure

Retire or thin-wrap old InvoiceLean names as aliases to InvoiceBase if needed for one release, then delete duplicates in LeanModels.cs.

Validation tests (`Novolis.Xsd.Unit`)

• Reflection: no byte[] anywhere under InvoiceBase graph
• OASIS Invoice → ToBase succeeds; attachment-heavy synthetic Wire with 2MB Value → Base allocated footprint ≪ Wire (reuse/strengthen heap test)
• ReminderBase round-trip of scalar spine fields
• Regenerated Generated/ is committed; CI can optionally run ubl-base and fail on dirty tree

Determinism checklist

1. Graph build order already sorted in `SchemaGraphBuilder`
2. Property emit order: attributes alpha, then particle DFS (document); same as Wire
3. SyntaxEmitWriter.Format only (no wall-clock)
4. Unit test golden: hash of concatenated relative path + source

Publish / hygiene

• Bump/publish Novolis.CodeGen.Xsd then Novolis.Xsd.Ubl.Lean (+ Generator/Tool) to GPR (2026.1.*)
• verify-nuget-only; regen Platform map if new packables (none expected)
• Update Lean README + hierarchy canvas “Proposed bases” to point at generated *Base

Out of scope

• Changing Wire Generated/ XmlSerializer models (bytes remain on Wire for fidelity)
• All ~65 maindocs as Base
• Schematron / Peppol rules
• Restoring binary on FromBase