chore(linter): Ensure that no unknown fields are allowed in OxlintOverride struct.

[connorshea]

Ensure that extra fields are not allowed inside overrides, to make it clear to users when they have added an invalid field.

Pulled out of #16822 since I think it's worth including regardless of that PR.

[charliecreates]

OxlintOverride now rejects unknown fields at both deserialization and schema-validation time, which is good for catching typos but can be behavior-breaking for any configs relying on ignored extra keys. The main risk is user experience: ensure there’s a regression test verifying the failure mode and that the surfaced error is actionable (field name + override index/path). Consider adding a brief schema/doc note clarifying that unknown keys are not permitted in overrides.

Additional notes (1)

• Readability | npm/oxlint/configuration_schema.json:505-510
  With additionalProperties: false added, schema consumers will now hard-fail on unknown keys. That’s desirable, but it often triggers churn if the schema is used by editors/validators that might add metadata (or if oxlint plans to add new override keys in the future). Consider whether you want to explicitly document this stricter behavior in the schema’s top-level markdownDescription (or relevant docs) so users know unknown keys are rejected rather than ignored.

Summary of changes

What changed

• Disallowed unknown fields in override configs by adding #[serde(deny_unknown_fields)] to OxlintOverride in crates/oxc_linter/src/config/overrides.rs.
• Updated the generated JSON Schema for OxlintOverride to include "additionalProperties": false.
  • Reflected in both the Rust snapshot crates/oxc_linter/src/snapshots/schema_json.snap and the published schema npm/oxlint/configuration_schema.json.

Result

Override objects now fail validation/deserialization when users provide extra/typoed keys, making configuration errors more visible and explicit.

[Copilot]

Pull request overview

This PR enhances configuration validation by ensuring that the OxlintOverride struct rejects unknown/invalid fields during deserialization. This helps users catch typos or invalid configuration options early by providing clear error messages.

Key Changes

• Added #[serde(deny_unknown_fields)] attribute to the OxlintOverride struct in Rust
• Added "additionalProperties": false to the corresponding JSON schema definition
• Updated the schema snapshot to reflect the JSON schema change

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
crates/oxc_linter/src/config/overrides.rs	Added #[serde(deny_unknown_fields)] to enforce strict field validation during deserialization
npm/oxlint/configuration_schema.json	Added "additionalProperties": false to the OxlintOverride schema for JSON validation
crates/oxc_linter/src/snapshots/schema_json.snap	Updated snapshot to match the JSON schema changes

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[codspeed-hq]

CodSpeed Performance Report

Merging #16870 will not alter performance

_{Comparing overrides-limit (b2273d7) with main (aafcf3e)¹}

Summary

✅ 4 untouched
⏩ 41 skipped²

Footnotes

1. No successful run was found on main (e0d8001) during the generation of this report, so aafcf3e was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 41 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[camc314]

Merge activity

• Dec 15, 9:43 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Dec 15, 9:43 AM UTC: camc314 added this pull request to the Graphite merge queue.
• Dec 15, 9:50 AM UTC: Merged by the Graphite merge queue.