gregfelice commented on issue #2490:
URL: https://github.com/apache/age/issues/2490#issuecomment-5169431971
The query as filed **passes on current `master`** — but it is masked rather
than fixed, so I would not close this without linking it to the underlying
defect.
**Environment:** `master` @ 80141740 (1.8.0), PostgreSQL 18.4, built from
source. You filed against 1.7.0.
```
value
--------
"PASS"
(1 row)
```
## Why it passes
The rule that governs this class of bug is that a reading clause sees only
the rows written by the **first input row** of a preceding writing clause. Your
`CREATE (a:N)-[:R {id:1}]->(b:N)` runs from a single input row, so its one edge
falls inside the visible window and the later `MATCH` finds it.
Drive the same shape from two input rows and it still returns the wrong
answer:
```sql
SELECT * FROM cypher('g', $cypher$
UNWIND [1,2] AS i
CREATE (a:N)-[:R {id:i}]->(b:N)
WITH [{id:1},{id:2}] AS items
UNWIND items AS item
MATCH ()-[r:R]->()
WHERE r.id = item.id
RETURN count(r) AS matched
$cypher$) AS (matched agtype);
```
Correct answer is `4` — four input rows reach the `MATCH`, each matching
exactly one edge. Actual is `2`: only the edge created by the first input row
(`id: 1`) is visible, so the two rows carrying `item.id = 2` match nothing.
Both edges do persist.
## Underlying defect
Same root cause as #2493, where I have written it up in full along with the
code references: the snapshot's `curcid` advances once per clause while
`CREATE` consumes one command id per input row, so everything written by input
rows 2..n stays invisible for the remainder of the statement.
Suggest tracking the fix under #2493 and keeping this issue open as the
1.7.0 report until that lands, or closing it with a pointer — whichever the
maintainers prefer.
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