Fix issue 1219 - MERGE not seeing previous clause var (#1441) #1443
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Fixed issue 1219 where MERGE did not see the previous clause's
variable.
This description is a bit misleading as the transform phase did see
the variable and was able to use it. However, the planner phase
removed the variable by replacing it with a NULL Const. This caused
MERGE to see a NULL Const for the previous tuple, generating
incorrect results. However, this only occurred for very specific
cases.
Fx: MATCH (x) MERGE (y {id: id(x)}) -- worked
MATCH (x) MERGE (y {id: id(x)}) RETURN y -- didn't
MATCH (x) MERGE (y {id: id(x)}) RETURN x, y -- worked
The change impacted no current regression tests and involved wrapping
all explicitly defined variables' target entries with a volatile
wrapper.
Added new regression tests.
rafsun42
approved these changes
Dec 11, 2023
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Fixed issue 1219 where MERGE did not see the previous clause's variable.
This description is a bit misleading as the transform phase did see the variable and was able to use it. However, the planner phase removed the variable by replacing it with a NULL Const. This caused MERGE to see a NULL Const for the previous tuple, generating incorrect results. However, this only occurred for very specific cases.
Fx: MATCH (x) MERGE (y {id: id(x)}) -- worked
MATCH (x) MERGE (y {id: id(x)}) RETURN y -- didn't
MATCH (x) MERGE (y {id: id(x)}) RETURN x, y -- worked
The change impacted no current regression tests and involved wrapping all explicitly defined variables' target entries with a volatile wrapper.
Added new regression tests.