Expected failures and unexpected exceptions

Question and use cases

Business failures remain typed Result data; only unexpected faults reach the exception handler.

Use this flow to choose between a typed Result and an exception, and to keep HTTP failures stable.

Use the diagram during design review, incident diagnosis, code walkthroughs, and onboarding. It intentionally omits classes and projects unrelated to the focused question, so read it together with the source entry point and related topic pages.

This page covers only the named responsibilities and relationships; consult the relevant module documentation for capabilities not shown here.

Reading path

1. Step 1: Classify the outcome as expected business failure or unexpected fault.
2. Step 2: Follow typed errors through endpoint mapping into Problem Details.
3. Step 3: Follow unexpected exceptions through the global handler and sanitization path.

Do not skip arrow direction, numbering, or group titles: they express dependency or time direction, execution order, and responsibility boundaries. If the diagram differs from current source or accepted architecture decisions, correct the generated catalog immediately.

Legend and notation

This is a ERROR FLOW diagram. Use that form to understand the layout, then test your interpretation against the source facts below.

Key relationships and design meaning

Relationship 1

Source fact: Expected domain and application failures return Result or Result<T> with a typed Error.

Architectural meaning: Typed expected failures remain part of the use-case contract and can be exhaustively mapped and tested.

Review action: Is the error code stable enough for a client contract?

Relationship 2

Source fact: Endpoints map typed errors to stable Problem Details status codes and error codes.

Architectural meaning: Stable Problem Details codes let clients branch on documented semantics instead of parsing messages.

Review action: Does a business branch avoid exception-driven control flow?

Relationship 3

Source fact: UseExceptionHandler catches unexpected faults and returns sanitized server errors.

Architectural meaning: The global exception path contains unknown faults and prevents internal exception data from becoming a public contract.

Review action: Could production details disclose internals or secrets?

Design review questions

Answer each question when reviewing or implementing a related change. If code, tests, or an ADR cannot support the answer, do not decide from the diagram alone.

• Is the error code stable enough for a client contract?
• Does a business branch avoid exception-driven control flow?
• Could production details disclose internals or secrets?

How to use the answers

1. Identify the single owner of the capability or rule.
2. Confirm that dependency, call, or event direction does not reverse ownership.
3. Capture the conclusion with an automated test or repeatable command.

Boundaries and common mistakes

Boundary 1

Do not throw exceptions for validation, not-found, conflict, or forbidden business outcomes.

• Do not infer: A connector in the diagram does not mean every implementation uses synchronous calls, a shared transaction, or shared data ownership.
• Review requirement: Does a business branch avoid exception-driven control flow?

Boundary 2

Never expose exception internals or secrets in production Problem Details.

• Do not infer: A connector in the diagram does not mean every implementation uses synchronous calls, a shared transaction, or shared data ownership.
• Review requirement: Could production details disclose internals or secrets?

Source verification and regeneration

The primary verification entry point is BitzOrcas.Domain/Results + BitzOrcas.Api/Results/ProblemDetailsMapper.cs. Inspect it and its direct references before regenerating diagram assets and pages.

# Regenerate bilingual SVG, standalone HTML, and documentation pages
npm run diagrams

# Check locale pairs, references, safety attributes, accessibility, and canvas bounds
npm run verify:diagrams

# Confirm that generation changed only the intended diagrams and pages
git diff -- scripts/diagrams diagram-sources public/diagrams src/content/docs

# Verify internal links, MDX structure, and professional depth gates
npm run verify:docs
npm run audit:docs-depth

Change-completion checklist

• Responsibilities, order, states, and relationships match current source.
• Every new element helps answer this page’s question instead of turning the diagram into an inventory.
• Arrows have explicit direction and semantics without implying nonexistent synchronous or transactional guarantees.
• Chinese and English titles, labels, facts, and boundaries remain semantically equivalent.
• The diagram remains readable on narrow screens, in fullscreen, and while zoomed, with no overlap or overflow.
• Relevant architecture tests, integration tests, or verification commands have run.
• If a long-lived constraint changed, its ADR or architecture documentation is updated.

Continue reading

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