[rb] validate nullable-constant BiDi params outbound

[titusfortner]

🔗 Related Issues

Closes item 3 (outbound local validation) of the low-level WebDriver BiDi behavioral contract proposed in #17786. Schema signal it relies on was added in #17700.

💥 What does this PR do?

• The internal BiDi layer now rejects an invalid value for a nullable-constant command param — emulation.setScriptingEnabled's enabled and browsingContext.setBypassCSP's bypass — with a local ArgumentError, instead of serializing an off-spec value onto the wire for the remote end to reject on a round-trip.
• Valid calls are unchanged: the spec literal or an explicit null still serialize exactly as before.
• This makes Ruby fully conformant with the contract's outbound-validation item (enum, required-field, unknown-property, and now const-literal membership).

🔧 Implementation Notes

• The shared schema already carried the {const, nullable} descriptor for these fields (since [js] Add binding-neutral BiDi schema with cddl2ts-gated fidelity #17700); the Ruby generator was consuming it only to type the RBS and dropping it from the runtime spec. This threads it through: the generator emits const: and the runtime Record validates it — no schema change needed.
• Non-nullable consts stay baked discriminators (auto-populated, unchanged); only nullable consts — which are settable literal-or-null — gain validation, so item 2 settability is preserved.
• enabled's const is false (the spec lets you disable scripting or clear the override, not force it on), so the check handles a falsy literal via sentinels rather than truthiness.

🤖 AI assistance

• No substantial AI assistance used
• AI assisted (complete below)
  • Tool(s): Claude Code
  • What was generated: the runtime const check in record.rb, the generator threading in bidi_generate.rb, the regenerated protocol files, and the test
  • I reviewed all AI output and can explain the change

🔄 Types of changes

• Bug fix (backwards compatible)

[selenium-ci]

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[qodo-code-review]

PR Summary by Qodo

Validate nullable const-literals for Ruby BiDi outbound params

🐞 Bug fix ✨ Enhancement 🧪 Tests ⚙️ Configuration changes 🕐 20-40 Minutes

AI Description

• Reject non-literal values for nullable-const BiDi params before sending them over the wire.
• Thread schema const through the Ruby generator into runtime Record validation.
• Add unit coverage for literal-or-null param enforcement and update lint/signature metadata.

Diagram

graph TD
  G["bidi_generate.rb"] --> P["Protocol param records"] --> R["Serialization::Record"] --> V["validate_const"] --> E["ArgumentError (local)"]
  T["serialization_spec.rb"] --> V --> E
  S["serialization.rbs"] --> V
  C[".rubocop.yml"] --> R

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High-Level Assessment

The following are alternative approaches to this PR:

1. Command-layer validation per API method

• ➕ Error messages could be tailored to each command and parameter name in the public API surface
• ➕ Avoids adding more validation paths inside the generic Record layer
• ➖ Duplicates logic across commands and languages/domains
• ➖ Easy to miss future nullable-const fields added to the schema
• ➖ Harder to keep aligned with the shared schema contract

2. Full JSON-schema validation on outbound payloads

• ➕ Generalizes beyond const/enum to richer constraints if adopted later
• ➕ Keeps validation rules declarative and centralized
• ➖ Higher runtime overhead and additional dependency surface
• ➖ Requires bridging schema format to a validator; more moving parts than needed for const-literals

Recommendation: The PR’s approach (thread const metadata from the schema into generated Record specs and validate in the shared Serialization::Record) is the best fit: it is schema-driven, applies uniformly across all generated commands, and prevents off-spec wire traffic without duplicating checks in command code. Per-command validation and full schema validation were plausible but would either drift from the shared schema or add unnecessary complexity for this targeted contract item.

Files changed (7) +65 / -18

Enhancement (2) +38 / -11

bidi_generate.rbThread schema const-literals into generated Record specs +36/-11

Thread schema const-literals into generated Record specs

• Extends the generator IR to include 'const', emits 'const:' in 'Record.define' specs when present, and adds 'leaf_const' to resolve const-literals through alias chains so runtime validation has the correct literal.

rb/lib/selenium/webdriver/bidi/support/bidi_generate.rb

serialization.rbsAdd RBS signature for const validation helper +2/-0

Add RBS signature for const validation helper

• Adds an RBS method signature for 'validate_const' to match the new runtime validation hook.

rb/sig/lib/selenium/webdriver/bidi/serialization.rbs

Bug fix (3) +19 / -7

browsing_context.rbMark bypass param as nullable const-literal +1/-1

Mark bypass param as nullable const-literal

• Updates 'BrowsingContext::SetBypassCSPParameters' to include 'const: true' alongside 'nullable: true', enabling runtime enforcement that the only non-null value is the spec literal.

rb/lib/selenium/webdriver/bidi/protocol/browsing_context.rb

emulation.rbMark enabled param as nullable const-literal (false) +1/-1

Mark enabled param as nullable const-literal (false)

• Updates 'Emulation::SetScriptingEnabledParameters' to include 'const: false' alongside 'nullable: true', ensuring outbound validation correctly handles a falsy literal constant.

rb/lib/selenium/webdriver/bidi/protocol/emulation.rb

record.rbAdd runtime validation for nullable const fields +17/-5

Add runtime validation for nullable const fields

• Extends Record field metadata to carry 'const', threads it through field construction, and adds 'validate_const' invoked during outbound validation to raise 'ArgumentError' when a provided value is neither the literal nor null.

rb/lib/selenium/webdriver/bidi/serialization/record.rb

Tests (1) +7 / -0

serialization_spec.rbTest rejection of non-literal values for literal-or-null params +7/-0

Test rejection of non-literal values for literal-or-null params

• Adds a unit test asserting that 'bypass: false' (must be true or null) and 'enabled: true' (must be false or null) raise 'ArgumentError' before serialization occurs.

rb/spec/unit/selenium/webdriver/bidi/serialization_spec.rb

Other (1) +1 / -0

.rubocop.ymlExclude BiDi Record from ModuleLength metrics +1/-0

Exclude BiDi Record from ModuleLength metrics

• Adds 'lib/selenium/webdriver/bidi/serialization/record.rb' to the RuboCop 'Metrics/ModuleLength' exclusion list to avoid lint failures after the added validation logic.

rb/.rubocop.yml

[qodo-code-review]

Code Review by Qodo

🐞 Bugs (0) 📘 Rule violations (0) 📎 Requirement gaps (0)

Great, no issues found!

Qodo reviewed your code and found no material issues that require review

[Copilot]

Pull request overview

This PR tightens the Ruby BiDi serialization layer to locally validate nullable-const outbound parameters (literal-or-null) so off-spec values are rejected with an ArgumentError before any wire round-trip, aligning Ruby with the outbound-validation behavioral contract referenced in #17786.

Changes:

• Thread { const, nullable } schema information through the Ruby BiDi generator into runtime Record.define specs (const: metadata).
• Add runtime validation in Serialization::Record to enforce const membership for non-nil outbound values.
• Add a unit regression spec covering the two affected nullable-const command params.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
rb/spec/unit/selenium/webdriver/bidi/serialization_spec.rb	Adds regression coverage ensuring invalid literal-or-null values raise locally.
rb/sig/lib/selenium/webdriver/bidi/serialization.rbs	Updates RBS signatures to include the new validate_const helper.
rb/lib/selenium/webdriver/bidi/support/bidi_generate.rb	Extends generator IR to carry and emit const: metadata for runtime validation.
rb/lib/selenium/webdriver/bidi/serialization/record.rb	Implements outbound const validation in Record construction.
rb/lib/selenium/webdriver/bidi/protocol/emulation.rb	Regenerates protocol to include const: false for enabled on SetScriptingEnabledParameters.
rb/lib/selenium/webdriver/bidi/protocol/browsing_context.rb	Regenerates protocol to include const: true for bypass on SetBypassCSPParameters.
rb/.rubocop.yml	Adjusts RuboCop exclusions for the updated record.rb.