[osipovartem]

Problem

With uppercase_unquoted_identifiers=true, recursive CTE planning reparses an already-normalized work-table name via TableReference::from(String), lowercasing its qualifier. References such as current_layer.component_id then fail. The same reparse occurs when decoding recursive work-table scans from protobuf, including quoted mixed-case names.

Change

Use TableReference::bare at both scan construction points to preserve the normalized or quoted name. Add SQL planner coverage and executable protobuf round-trip coverage for uppercase unquoted and quoted mixed-case CTEs. The default identifier mode remains unchanged.

Verification

• cargo +1.97.0 test -p datafusion-sql --test sql_integration recursive_cte_preserves_normalized_and_quoted_names
• cargo +1.97.0 test -p datafusion-proto --test proto_integration (234 passed)
• cargo +1.97.0 clippy -p datafusion-proto -p datafusion-sql --all-targets
• cargo +1.97.0 fmt --all --check
• Independent read-only review: approved, no blocking correctness, performance, API, or test gaps.