fix(snowflake): PIVOT/UNPIVOT — chained-clause parse, deparse, and lineage soundness#300
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…ard) — lineage soundness
The T5.3 node already parsed PIVOT/UNPIVOT into TableRef.Pivot/.Unpivot,
but three downstream gaps still silently treated 'FROM t PIVOT(...)' as
bare 'FROM t':
- parser: a chained 'PIVOT(...) PIVOT(...)' (official docs, corpus
example_20) mis-parsed — the second PIVOT keyword was eaten as the
first clause's implicit alias and the second clause body silently
discarded. parseTableSuffix now loops, re-rooting the ref in place
with the prior pivoted source on the new TableRef.Nested field, and
the clause trailing alias refuses a PIVOT/UNPIVOT-plus-'(' head.
- deparse: writeTableRef dropped Pivot/Unpivot entirely, so any rewrite
consumer would emit the unpivoted relation. Both clauses (and Nested
chains) now round-trip.
- analysis/query_span: pivoted relations resolved as their base table,
fabricating per-column attributions for output columns that do not
exist on the base (e.g. T."2023_Q1" for SUM(T.AMOUNT) data) — an
under-attribution leak for masking consumers. Pivoted refs now
resolve as opaque-derived entries: every column resolved through
them (star, bare, or alias-qualified) attributes to the source
relation's whole-relation ('*') sources, deliberately conservative.
Walker regenerated for Nested (genwalker guard green); ast.Inspect
reaches both clauses of a chain and the IN-list values.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Fix
PIVOT/UNPIVOT soundness (found by bytebase cutover P1 review): the AST nodes existed (#261) but (1) chained
t PIVOT(...) PIVOT(...)mis-parsed (2nd keyword eaten as implicit alias, clause dropped), (2) deparse emitted nothing for Pivot/Unpivot, (3) analysis resolved pivoted refs as the bare base table, fabricating source columns likeT."2023_Q1"(under-attribution leak).New
TableRef.Nestedfor chains; alias guard refuses PIVOT/UNPIVOT clause heads; deparse round-trips all forms; analysis attributes every column through a pivoted relation to whole-relation sources (masking-sound over-attribution, matching the catalog-less convention). 23 new tests; full suite + corpus green; walker regenerated (guard green). Verified on fresh checkout of aeadf5d.Residual chips filed: parser-wide trailing-token drop; MATCH_RECOGNIZE same-class.
🤖 Generated with Claude Code