PDGGK opened a new pull request, #9405:
URL: https://github.com/apache/paimon/pull/9405
### Purpose
`IcebergRef.equals` compares `maxRefAgeMs` with `==`, and that field is a
boxed
`Long`:
```java
// IcebergRef.java:50
@Nullable private final Long maxRefAgeMs;
// :85-87
return snapshotId == that.snapshotId
&& type.equals(that.type)
&& maxRefAgeMs == that.maxRefAgeMs;
```
So the comparison is on references, not values. It would still work if the
two
boxes happened to be the same object, but the constructor guarantees they are
not:
```java
// :53-60
public IcebergRef(@JsonProperty(FIELD_SNAPSHOT_ID) long snapshotId) {
this.snapshotId = snapshotId;
this.type = "tag";
this.maxRefAgeMs = Long.MAX_VALUE;
}
```
`Long.MAX_VALUE` is far outside the `Long` cache, so every `new
IcebergRef(..)`
autoboxes a fresh object and
```java
new IcebergRef(1L).equals(new IcebergRef(1L)) // false
```
`hashCode` was already written the other way:
```java
// :91-93
return Objects.hash(snapshotId, type, maxRefAgeMs);
```
which is value-based. The two therefore disagree: refs that hash to the same
bucket compare unequal, so a `HashSet<IcebergRef>` keeps both copies rather
than
deduplicating.
It does not stop there. `IcebergMetadata.equals` compares its refs map:
```java
// IcebergMetadata.java:371
&& Objects.equals(refs, that.refs);
```
`Map.equals` compares values with `equals`, so two `IcebergMetadata` carrying
identical tags are reported as different.
### What changes
```java
return snapshotId == that.snapshotId
&& Objects.equals(type, that.type)
&& Objects.equals(maxRefAgeMs, that.maxRefAgeMs);
```
`Objects` is already imported. `type` is switched over at the same time — it
is
non-null in practice, but there is no reason for one field in the expression
to
be able to throw while the others cannot.
### Test
`IcebergRefTest`, three cases, one per layer the defect reaches:
* `testEqualsIsByValue` — two refs built with the same snapshot id are
equal, and
refs with different ids are not
* `testEqualObjectsShareAHashCode` — the hashCodes match, and a `HashSet`
holding
both ends up with one element
* `testMetadataComparesItsRefsByValue` — two `Map<String, IcebergRef>` with
the
same content compare equal, which is the shape `IcebergMetadata.equals`
relies
on
Reverting only the `equals` body, on a forced clean rebuild of `paimon-core`,
fails all three — at three different levels rather than all on the same
assertion.
Wider run: `*Iceberg*` across `paimon-core` — 167 tests, 0 failures.
### API and Format
No change to any option, on-disk format or public signature.
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