Fix that MERGE did not enforce relationship uniqueness. #10771
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| @@ -30,23 +30,23 @@ class NameMatchPatternElementTest extends CypherFunSuite { | |||
| val original = parser.parse("MATCH (n)-[r:Foo]->() RETURN n") | |||
| val expected = parser.parse("MATCH (n)-[r:Foo]->(` UNNAMED20`) RETURN n") | |||
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| val result = original.rewrite(nameMatchPatternElements) | |||
| val result = original.rewrite(nameMatchAndMergePatternElements) | |||
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This test class could also test MERGE clauses
| graph.execute("CREATE (a) CREATE (a)-[:X]->(a)") | ||
| val result = updateWithBothPlannersAndCompatibilityMode("MERGE (a)-[:X]->(b)-[:X]->(c) RETURN 42") | ||
| assertStats(result, relationshipsCreated = 2, nodesCreated = 3) | ||
| } |
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Since the fix seems relevant to all predicates, perhaps we should have more tests:
- Test for relationship uniqueness without self-relationships
- Test for other predicates than relationship uniqueness
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I've notice that the second case is already covered by the fact that Cypher does not allow explicit WHERE clauses for MERGE, and the implicit WHERE from in-lined Label and Property checks was already checked for separately, so the only predicate not covered was relationship uniqueness, which is good. I the meantime I have written a test for the first case.
| @@ -47,7 +47,7 @@ class ASTRewriter(rewriterSequencer: (String) => RewriterStepSequencer, shouldEx | |||
| enableCondition(containsNoReturnAll), | |||
| foldConstants, | |||
| ApplyRewriter("extractParameters", extractParameters), | |||
| nameMatchPatternElements, | |||
| nameMatchAndMergePatternElements, | |||
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There is already a nameUpdatingClauses Rewriter. That could be used here instead of changing nameMatchPatternElements
Add predicates to MERGE clauses, so that our addUniquenessPredicates rewriter is able to
add a uniqueness predicate.