validate: review-driven correctness and consistency fixes

[jqnatividad]

Summary

Fixes from a code review of src/cmd/validate.rs:

• DynEnumValidator::validate — replaced instance.as_str().unwrap() with the Value::String pattern that is_valid already uses. The old code panics if validate is ever entered with a non-string instance.
• split_invalid_records off-by-one — changed > to >= in the bounds check. The old guard fires one row late, so when the input file has more rows than valid_flags (file grew between passes, or --fail-fast truncation), the next iteration indexes valid_flags[valid_flags_len] and panics.
• Lite-mode dyn_enum_validator_factory — was silently defaulting to column 0 when the named column wasn't found or when rdr.headers() errored, which built dynamicEnum sets from the wrong column with no warning. Now mirrors the non-lite version and returns a proper validation error.
• Unnecessary unsafe { unwrap_unchecked } in the Rayon validation loop — both call sites are already gated by std::hint::cold_path(), so the perf savings are zero. Replaced with safe unwrap() plus a one-line comment explaining why it cannot fire (row number is appended via itoa, always valid ASCII).
• to_json_instance NaN/inf handling — fast_float2::parse accepts "NaN"/"inf", then Number::from_f64 rejects non-finite floats and the old fallback silently coerced to 0. That would let invalid numbers slip past schema constraints like minimum/maximum. Now surfaces a Non-finite Number error.

Three other issues flagged during review were investigated and dismissed — see commit message and PR conversation for details (no real race in UniqueCombinedWithValidator, no Windows file-handle conflict in split_invalid_records, obj.values() ordering is correct because serde_json is built with preserve_order).

Test plan

• cargo test test_validate -F all_features — 62/62 pass
• cargo test test_validate -F lite — 62/62 pass (after updating validate_dynenum_with_invalid_column lite assertion to match the new correct error path; the old assertion was asserting the silent-fallback bug)
• cargo clippy --bin qsv -F all_features -- -D warnings — clean
• cargo build --bin qsv -F all_features — clean

🤖 Generated with Claude Code

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

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0 new issues

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[Copilot]

Pull request overview

This PR applies review-driven correctness fixes to the validate command’s JSON Schema validation path, primarily preventing panics and eliminating silent mis-validation.

Changes:

• Prevent panics and silent fallbacks in dynamicEnum validation (string-only validate, proper “column not found” errors in lite mode).
• Fix an off-by-one bounds check when splitting valid/invalid outputs to avoid indexing past valid_flags.
• Improve numeric casting correctness by surfacing non-finite float values (NaN/±inf) as errors instead of coercing to 0.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/cmd/validate.rs	Correctness and consistency fixes across dynamicEnum validation, splitting logic, error-path UTF-8 handling, and number parsing.
tests/test_validate.rs	Updates lite-mode assertion to match the new (correct) dynamicEnum error behavior instead of the prior silent fallback.