feat: validate snapshot write compatibility

Author: kaushiksrini

pyiceberg/table/update/snapshot.py

@@ -80,6 +80,7 @@
 from pyiceberg.utils.bin_packing import ListPacker
 from pyiceberg.utils.concurrent import ExecutorFactory
 from pyiceberg.utils.properties import property_as_bool, property_as_int
+from pyiceberg.utils.snapshot import ancestors_between
 
 if TYPE_CHECKING:
     from pyiceberg.table import Transaction
@@ -251,6 +252,12 @@ def _commit(self) -> UpdatesAndRequirements:
         )
         location_provider = self._transaction._table.location_provider()
         manifest_list_file_path = location_provider.new_metadata_location(file_name)
+
+        # get current snapshot id and starting snapshot id, and validate that there are no conflicts
+        starting_snapshot_id = self._parent_snapshot_id
+        current_snapshot_id = self._transaction._table.refresh().metadata.current_snapshot_id
+        self._validate(starting_snapshot_id, current_snapshot_id)
+
         with write_manifest_list(
             format_version=self._transaction.table_metadata.format_version,
             output_file=self._io.new_output(manifest_list_file_path),
@@ -279,6 +286,27 @@ def _commit(self) -> UpdatesAndRequirements:
             (AssertRefSnapshotId(snapshot_id=self._transaction.table_metadata.current_snapshot_id, ref="main"),),
         )
 
+    def _validate(self, starting_snapshot_id: Optional[int], current_snapshot_id: Optional[int]) -> None:
+        # get all the snapshots between the current snapshot id and the parent id
+        snapshots = ancestors_between(starting_snapshot_id, current_snapshot_id, self._transaction._table.metadata.snapshot_by_id)
+
+        # Define allowed operations for each type of operation
+        allowed_operations = {
+            Operation.APPEND: {Operation.APPEND, Operation.REPLACE, Operation.OVERWRITE, Operation.DELETE},
+            Operation.REPLACE: {Operation.APPEND},
+            Operation.OVERWRITE: set(),
+            Operation.DELETE: set(),
+        }
+
+        for snapshot in snapshots:
+            snapshot_operation = snapshot.summary.operation
+
+            if snapshot_operation not in allowed_operations[self._operation]:
+                raise ValueError(
+                    f"Operation {snapshot_operation} is not allowed when performing {self._operation}. "
+                    "Check for overlaps or conflicts."
+                )
+
     @property
     def snapshot_id(self) -> int:
         return self._snapshot_id

pyiceberg/utils/snapshot.py

@@ -0,0 +1,53 @@
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing,
+#  software distributed under the License is distributed on an
+#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+
+from typing import Callable, Iterable, Iterator, Optional
+from pyiceberg.table.snapshots import Snapshot
+
+
+def ancestors_of(snapshot_id: Optional[int], lookup_fn: Callable[[int], Optional[Snapshot]]) -> Iterable[Snapshot]:
+    def _snapshot_iterator(snapshot: Snapshot) -> Iterator[Snapshot]:
+        next_snapshot: Optional[Snapshot] = snapshot
+        consumed = False
+
+        while next_snapshot is not None:
+            if not consumed:
+                yield next_snapshot
+                consumed = True
+
+            parent_id = next_snapshot.parent_snapshot_id
+            if parent_id is None:
+                break
+
+            next_snapshot = lookup_fn(parent_id)
+            consumed = False
+    
+    snapshot: Optional[Snapshot] = lookup_fn(snapshot_id)
+    if snapshot is not None:
+        return _snapshot_iterator(snapshot)
+    else:
+        return iter([])
+
+def ancestors_between(starting_snapshot_id: Optional[int], current_snapshot_id: Optional[int], lookup_fn: Callable[[int], Optional[Snapshot]]) -> Iterable[Snapshot]:
+    if starting_snapshot_id == current_snapshot_id:
+        return iter([])
+    
+    return ancestors_of(
+        current_snapshot_id, 
+        lambda snapshot_id: lookup_fn(snapshot_id) if snapshot_id != starting_snapshot_id else None
+    )
+