Enforce positive retention values on SetSnapshotRefUpdate

SnapshotRef requires min-snapshots-to-keep, max-snapshot-age-ms and
max-ref-age-ms to be greater than 0, but SetSnapshotRefUpdate did not,
so an invalid value only failed when the ref was built at apply time.
Java validates these in SnapshotRef.Builder when they are set.

Author: Ferdinanddb

pyiceberg/table/update/__init__.py

@@ -138,9 +138,9 @@ class SetSnapshotRefUpdate(IcebergBaseModel):
     ref_name: str = Field(alias="ref-name")
     type: Literal[SnapshotRefType.TAG, SnapshotRefType.BRANCH]
     snapshot_id: int = Field(alias="snapshot-id")
-    max_ref_age_ms: Annotated[int | None, Field(alias="max-ref-age-ms", default=None)]
-    max_snapshot_age_ms: Annotated[int | None, Field(alias="max-snapshot-age-ms", default=None)]
-    min_snapshots_to_keep: Annotated[int | None, Field(alias="min-snapshots-to-keep", default=None)]
+    max_ref_age_ms: Annotated[int | None, Field(alias="max-ref-age-ms", default=None, gt=0)]
+    max_snapshot_age_ms: Annotated[int | None, Field(alias="max-snapshot-age-ms", default=None, gt=0)]
+    min_snapshots_to_keep: Annotated[int | None, Field(alias="min-snapshots-to-keep", default=None, gt=0)]
 
 
 class RemoveSnapshotsUpdate(IcebergBaseModel):

tests/table/test_manage_snapshots.py

@@ -18,6 +18,7 @@
 from uuid import uuid4
 
 import pytest
+from pydantic import ValidationError as PydanticValidationError
 
 from pyiceberg.table import CommitTableResponse, Table
 from pyiceberg.table.refs import SnapshotRef, SnapshotRefType
@@ -391,3 +392,13 @@ def test_fast_forward_branch_unknown_snapshot(table_v2: Table) -> None:
         table_v2.manage_snapshots().fast_forward_branch(from_branch="main", to_ref="dangling")
 
     table_v2.catalog.commit_table.assert_not_called()
+
+
+def test_create_branch_invalid_retention(table_v2: Table) -> None:
+    table_v2.catalog = MagicMock()
+
+    # rejected when passed, not when the ref is built
+    with pytest.raises(PydanticValidationError, match="min_snapshots_to_keep"):
+        table_v2.manage_snapshots().create_branch(snapshot_id=PARENT_SNAPSHOT_ID, branch_name="b", min_snapshots_to_keep=0)
+
+    table_v2.catalog.commit_table.assert_not_called()