[build] derive per-type inbound/outbound directionality in the shared schema

[titusfortner]

🔗 Related Issues

Builds on the shared BiDi schema projector (#17700).

💥 What does this PR do?

• The shared BiDi schema now records, per structured type, whether a caller sends it (outbound), receives it (inbound), or both.
• Every language binding can now read one authoritative signal to tell send-side types from receive-only ones, instead of each re-deriving it.

🔧 Implementation Notes

• inbound and outbound are independent booleans, so all four combinations are meaningful — a type used both ways (network.Cookie) is (true, true); a flattened base or message envelope that is part of no message is (false, false).
• Additive and backward compatible

🤖 AI assistance

• No substantial AI assistance used
• AI assisted (complete below)
  • Tool(s): Claude Code
  • What was generated: the directionality pass in the schema projector and its unit tests
  • I reviewed all AI output and can explain the change

💡 Additional Considerations

• Follow-on PR for Ruby to implement outbound-scoped domain accessors

🔄 Types of changes

• New feature (non-breaking change which adds functionality and tests!)

[qodo-code-review]

PR Summary by Qodo

Derive per-type inbound/outbound reachability flags in shared BiDi schema

✨ Enhancement 🧪 Tests 🕐 20-40 Minutes

AI Description

• Compute per-structured-type inbound/outbound flags from command/event message reachability.
• Reuse a single ref-walk implementation for both integrity checks and directionality.
• Add unit tests covering all flag combinations and validator behavior.

Diagram

graph TD
  M["Model (commands/events)"] --> P["projectSchema()"] --> R["reachableTypes()"] --> T[("schema.types")]
  T --> CS["checkSchema()"] --> OK["Validators pass"]
  T --> CC["checkCompleteness()"] --> OK
  TEST["project_bidi_schema_test.mjs"] --> P

  subgraph Legend
    direction LR
    _p["Process"] ~~~ _d[("Data")]
  end

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High-Level Assessment

The following are alternative approaches to this PR:

1. Heuristic directionality (name-based or domain-based)

• ➕ Lower implementation effort; no graph traversal needed
• ➕ May be sufficient for simple schemas with strong naming conventions
• ➖ Incorrect when structurally identical types differ by use-site (the PR explicitly tests this)
• ➖ Brittle to schema evolution; encourages binding-specific divergence

2. Derive directionality during codegen per language

• ➕ Keeps schema simpler; avoids adding new fields to shared schema
• ➕ Allows generator-specific nuance in defining “send-side” vs “receive-side”
• ➖ Reintroduces duplicated logic across bindings (the problem this PR solves)
• ➖ Harder to keep consistent across languages and releases

3. Manually annotate directionality in the source CDDL/model

• ➕ Explicit and potentially easier to reason about for humans
• ➕ Avoids depending on reachability semantics if they ever change
• ➖ Ongoing maintenance burden; easy to forget to update
• ➖ More error-prone than a computed property; needs additional validation anyway

Recommendation: Keep the PR’s reachability-based computation in the shared projector. It is binding-neutral, robust to structural look-alikes, and reuses the same reference edges as schema validation, minimizing drift between “what the schema means” and “what the validators enforce.”

Files changed (2) +182 / -18

Enhancement (1) +80 / -18

project_bidi_schema.mjsAdd reachability-based inbound/outbound flags to projected structured types +80/-18

Add reachability-based inbound/outbound flags to projected structured types

• Introduces shared helpers to extract referenced type names and compute transitive reachability over projected type nodes. Uses command params refs as outbound roots and command result + event params refs as inbound roots, then annotates every record/union with boolean inbound/outbound flags. Updates schema validation to reuse the shared ref extraction, and extends completeness checks to fail if a structured type is missing either flag.

javascript/selenium-webdriver/project_bidi_schema.mjs

Tests (1) +102 / -0

project_bidi_schema_test.mjsAdd unit tests for directionality flags and completeness enforcement +102/-0

Add unit tests for directionality flags and completeness enforcement

• Adds a new test suite that constructs a minimal AST/model to verify all four directionality combinations, including types reachable from neither side. Ensures structurally similar types are split purely by reachability (not name), validates that checkSchema/checkCompleteness pass for correct schemas, and asserts completeness fails closed if a flag is missing. Also confirms enums/aliases are not required to carry directionality flags.

javascript/selenium-webdriver/project_bidi_schema_test.mjs

[qodo-code-review]

Code Review by Qodo

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