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or whose variables no earlier clause binds returns no rows #610
Description
Found while fixing #608 (PR #609).
Repro
(transact [[:a :edge :b] [:b :edge :c]])
(query [:find ?p :where (or [?p :edge :b] [?p :edge :c])])
; ok: 2 rows (:a, :b)
(query [:find ?x ?p :where [?x :edge ?z] (or [?p :edge :b] [?p :edge :c])])
; No results — expected 4 rows (?x ∈ {:a, :b} × ?p ∈ {:a, :b})
(query [:find ?x ?p :where [?x :edge ?z] (or-join [?p] [?p :edge :b] [?p :edge :c])])
; INT-018 "join variable ?p in (or-join ...) is not bound by any earlier clause"An or placed after other clauses, whose branch variables none of those clauses bind, returns no rows. It should join as a cross product. It only uses patterns, so rules and magic sets are not involved. The same or on its own works.
or-join refuses the same shape with INT-018. So or silently returns an empty answer where or-join reports an error. One of the two needs to change: either or evaluates the shape, or it is refused the same way.
Activity
test(or): cross product after a pseudo-attribute clause (#610)
Merge pull request #612 from project-minigraf/fix/610-or-cross-product
fix(or): join an or sharing no variable with earlier clauses as a cro…
adityamukho commentedon Oct 16, 2026
Fixed on v3 by #612 (8e1f771) and backported to main by #613 (c21168f, ships in the next v2.0.x patch). An
orsharing no variable with the earlier clauses now joins as a cross product;or-joinkeeps INT-018, since it filters rather than binds.release: v2.0.7