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Fact with more than 4 elements: elements after the valid-time map are silently dropped #649
Description
Summary
parse_transact accepts a fact with more than four elements when the fourth is a map, and drops everything after the map without an error:
(transact [[:alice :person/age 1 {} 99 :junk]])
succeeds and stores only [:alice :person/age 1]. A caller who builds a fact with a misplaced bracket (for example two facts run together) loses data silently.
- Affected: every release from v0.4.0 (per-fact valid-time maps) through v2.0.8, and
v3. Before v0.4.0,Pattern::from_ednrequired exactly three elements. - Cause:
parse_transactchecksfact_vec.len() < 3and readsfact_vec.get(3)as the optional map, but never checks the length is at most 4. - Workaround: none needed for well-formed input; check that each fact vector has 3 elements, or 4 with a map last.
Fix
Reject a fact of more than four elements with its own PRS code (v3), and the same check on main for a v2.0.x patch.
Found by the grammar verifier (#643): it is the FactArity entry of
10760
KNOWN_DRIFT in src/query/datalog/parser/verifier.rs, which the fix removes. grammar.pest's fact is now exact ([e a v valid_time_map?]).
Activity
Merge pull request #654 from project-minigraf/fix/649-fact-arity
fix(parser): reject a fact with more than four elements, PRS-108 (#649)…
adityamukho commentedon Oct 20, 2026
Fixed on v3 in #654 (aa36639) and backported to main in #656 (5f364ab): a fact of more than four elements now fails with
PRS-108and the transaction writes nothing. Stays open until v2.0.9 is published.release: v2.0.9
adityamukho commentedon Oct 21, 2026
Fixed in v2.0.9 (released 2026-10-21, on crates.io) and in v3.0.0. Listed under "Fixed in v2.0.9" in #421.