Validate snapshot sequence numbers on v3 tables (#4125)

* fix(table): validate snapshot sequence numbers on v3 tables

The check that rejects a snapshot whose sequence number is not greater
than the table's last sequence number only ran for format version 2.
Java applies it to every format version after 1.

* test: derive expected sequence number from the fixture

The stale sequence-number test built the snapshot from the fixture's
last_sequence_number but hardcoded 34 in the expected error message.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Kevin Liu <kevin.jq.liu@gmail.com>
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: 3 people

pyiceberg/table/update/__init__.py

@@ -453,7 +453,7 @@ def _(update: AddSnapshotUpdate, base_metadata: TableMetadata, context: _TableMe
     elif base_metadata.snapshot_by_id(update.snapshot.snapshot_id) is not None:
         raise ValueError(f"Snapshot with id {update.snapshot.snapshot_id} already exists")
     elif (
-        base_metadata.format_version == 2
+        base_metadata.format_version >= 2
         and update.snapshot.sequence_number is not None
         and update.snapshot.sequence_number <= base_metadata.last_sequence_number
         and update.snapshot.parent_snapshot_id is not None

tests/table/test_init.py

@@ -2084,6 +2084,30 @@ def test_add_snapshot_update_fails_with_smaller_first_row_id(table_v3: Table) ->
         update_table_metadata(table_v3.metadata, (AddSnapshotUpdate(snapshot=new_snapshot),))
 
 
+@pytest.mark.parametrize("table", [lf("table_v2"), lf("table_v3")])
+def test_add_snapshot_update_fails_with_stale_sequence_number(table: Table) -> None:
+    last_sequence_number = table.metadata.last_sequence_number
+    new_snapshot = Snapshot(
+        snapshot_id=25,
+        parent_snapshot_id=3055729675574597004,
+        sequence_number=last_sequence_number,
+        timestamp_ms=1602638593590,
+        manifest_list="s3:/a/b/c.avro",
+        summary=Summary(Operation.APPEND),
+        schema_id=1,
+        first_row_id=2,
+    )
+
+    with pytest.raises(
+        ValueError,
+        match=(
+            f"Cannot add snapshot with sequence number {last_sequence_number} "
+            f"older than last sequence number {last_sequence_number}"
+        ),
+    ):
+        update_table_metadata(table.metadata, (AddSnapshotUpdate(snapshot=new_snapshot),))
+
+
 def test_add_snapshot_update_updates_next_row_id(table_v3: Table) -> None:
     new_snapshot = Snapshot(
         snapshot_id=25,