Incorrect Output from `list_namespaces` in `SqlCatalog`

[alessandro-nori]

Apache Iceberg version

main (development)

Please describe the bug 🐞

When a namespace is provided as a parameter, SqlCatalog.list_namespaces(namespace) returns the namespace itself.

>>> import pyiceberg
>>> pyiceberg.__version__
'0.9.0'
>>> from pyiceberg.catalog.sql import SqlCatalog
>>> catalog = SqlCatalog("example", **{"uri":"sqlite:///:memory:", "warehouse":"/tmp/pyiceberg/warehouse"})
>>> catalog.list_namespaces()
[]
>>> catalog.create_namespace("ns1.ns2")
>>> catalog.create_namespace("ns1.ns2.ns3")
>>> catalog.list_namespaces()
[('ns1', 'ns2'), ('ns1', 'ns2', 'ns3')]
>>> catalog.create_namespace("ns1")
>>> catalog.list_namespaces()
[('ns1',), ('ns1', 'ns2'), ('ns1', 'ns2', 'ns3')]
>>> catalog.list_namespaces("ns1")
[('ns1',)]

Expected behavior

Similar to other catalog implementations, calling list_namespaces with a namespace as a parameter should return only the sub-namespaces, excluding the namespace itself.

e.g. for other python catalogs

• GlueCatalog:

  iceberg-python/tests/catalog/integration_test_glue.py

  Line 321 in 7a4734e

  assert len(test_catalog.list_namespaces(list(database_list)[0])) == 0

• DynamoDbCatalog:

  iceberg-python/tests/catalog/integration_test_dynamodb.py

  Line 213 in 7a4734e

  assert len(test_catalog.list_namespaces(list(database_list)[0])) == 0

And the for the JdbcCatalog in Java:

• Implementation reference: https://github.com/apache/iceberg/blob/746e71931a35e83726852a60d7ca8cb6065e334f/core/src/main/java/org/apache/iceberg/jdbc/JdbcCatalog.java#L459-L460
• UnitTest: https://github.com/apache/iceberg/blob/41b458b7022c7b0cd78eeca9102392db7889d3c9/core/src/test/java/org/apache/iceberg/jdbc/TestJdbcCatalog.java#L747

Willingness to contribute

• I can contribute a fix for this bug independently
• I would be willing to contribute a fix for this bug with guidance from the Iceberg community
• I cannot contribute a fix for this bug at this time

[kevinjqliu]

Thanks for raising this issue! Yea, the behavior should align with the java implementation and other catalogs.

[kevinjqliu]

assigned this issue to you. feel free to tag me for review.

[kevinjqliu]

This is another reason why I raised #813. It'll be great to modify our existing test suite to test behaviors across all catalogs