feat(cypher): coalesce(var.prop, literal) in WHERE clauses#1034
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July 11, 2026 17:09
The WHERE parser rejected coalesce() outright ('unexpected operator'),
blocking null-safe numeric filters over optional graph properties —
the exact audit-query shape from the report:
MATCH (f:Function) WHERE coalesce(f.transitive_loop_depth, 0) >= 2
RETURN-side coalesce already worked; only the WHERE leaf lacked it.
Implementation: the condition leaf gains a coalesce_default literal.
The operator/value tail of condition parsing is factored into a shared
parse_condition_op so both subjects (var[.prop] and
coalesce(var.prop, literal)) accept the full operator set (comparisons,
IS [NOT] NULL, IN). At eval time a missing/empty property value is
substituted with the default before the operator runs. Supported form
is coalesce(var.prop, literal) — matching openCypher's two-argument
null-substitution for this subset.
Reproduce-first: cypher_exec_where_coalesce_issue874 runs the
reporter's exact query — RED (rc=-1 parse error) on the old parser —
and pins both directions: a failing default excludes property-less
nodes, a passing default includes them.
Closes #874
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
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Closes #874.
WHERE coalesce(f.transitive_loop_depth, 0) >= 2— the reporter's exact null-safe audit filter — parsed with 'unexpected operator'. RETURN-sidecoalescealready existed; the WHERE leaf now supports it too.Design: the condition leaf carries an optional
coalesce_defaultliteral; the operator/value tail is factored into a sharedparse_condition_op, so the coalesce subject accepts the full operator set (comparisons,IS [NOT] NULL,IN) identically to a barevar.prop. Eval substitutes the default for missing/empty property values — real openCypher two-arg null-substitution semantics, not a rewrite trick.Reproduce-first: the reporter's query is the test — RED (
rc=-1) on the old parser; GREEN pins both directions (failing default excludes property-less nodes, passing default includes them).Full suite 5,997/0, lint-ci clean.