Silence6666668 opened a new issue, #2382:
URL: https://github.com/apache/age/issues/2382
**Describe the bug**
Variable-length relationship patterns with a zero lower bound may fail to
produce the expected zero-hop self-binding.
In the repro below, the graph contains a single `Person` node and no
`FRIEND` relationships. Under Cypher semantics, the pattern `[:FRIEND*0..1]`
should still match with length `0`, so `f` should bind to the same node as `p`.
Instead, Apache AGE returns `f = null`, and `collect(f.name)` becomes `[]`
instead of `['Alice']`.
**How are you accessing AGE (Command line, driver, etc.)?**
- PostgreSQL `cypher(...)` wrapper through the local Python
differential-testing harness
- Reproducible directly in `psql` inside the Docker container
**What data setup do we need to do?**
```pgsql
SELECT * FROM cypher('fuzz_graph', $$
CREATE (:Person {name: 'Alice'})
$$) AS (v agtype);
```
**What is the necessary configuration info needed?**
- Plain Apache AGE Docker image was enough
- Docker image in local repro: `apache/age`
- AGE extension version: `1.7.0`
- PostgreSQL version: `18.1`
- Graph name used in repro: `fuzz_graph`
- No extra extensions or special configuration were required
**What is the command that caused the error?**
```pgsql
SELECT * FROM cypher('fuzz_graph', $$
MATCH (p:Person {name: 'Alice'})
OPTIONAL MATCH (p)-[:FRIEND*0..1]-(f:Person)
RETURN p.name AS person, f.name AS friend
$$) AS (person agtype, friend agtype);
```
Returned result on AGE:
```text
person | friend
-------+-------
Alice | null
```
**Expected behavior**
The zero-hop match should bind `f` to the same node as `p`, so the expected
result is:
```text
person | friend
-------+-------
Alice | Alice
```
Neo4j returns exactly that result for the equivalent Cypher query.
**Environment (please complete the following information):**
- Version: Apache AGE `1.7.0`
- PostgreSQL: `18.1`
- Host OS: Windows 10
- Architecture: x86_64
- Deployment: Docker
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