bahman/scylla
1
0
Fork 0
Code Issues Pull Requests Actions 2 Packages Projects Releases Wiki Activity

alternator: allow REMOVE of non-existent nested attribute

Browse Source 
DynamoDB allows an UpdateItem operation "REMOVE x.y" when a map x
exists in the item, but x.y doesn't - the removal silently does
nothing. Alternator incorrectly generated an error in this case,
and unfortunately we didn't have a test for this case.

So in this patch we add the missing test (which fails on Alternator
before this patch - and passes on DynamoDB) and then fix the behavior.
After this patch, "REMOVE x.y" will remain an error if "x" doesn't
exist (saying "document paths not valid for this item"), but if "x"
exists and is a map, but "x.y" doesn't, the removal will silently
do nothing and will not be an error.

Fixes #10043.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20220207133652.181994-1-nyh@scylladb.com>
This commit is contained in:
Nadav Har'El
2022-02-07 15:36:52 +02:00
committed by Avi Kivity
parent 31f4cd21eb
commit 9982a28007
2 changed files with 16 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
alternator/executor.cc
View File

@@ -2577,8 +2577,8 @@ static bool hierarchy_actions(
// attr member so we can use add()
rjson::add_with_string_name(v, attr, std::move(*newv));
} else {
throw api_error::validation(format("Can't remove document path {} - not present in item",
subh.get_value()._path));
// Removing a.b when a is a map but a.b doesn't exist
// is silently ignored. It's not considered an error.
}
} else {
throw api_error::validation(format("UpdateExpression: document paths not valid for this item:{}", h));

14
test/alternator/test_update_expression.py
View File

@@ -1030,6 +1030,20 @@ def test_nested_attribute_remove_from_missing_item(test_table_s):
test_table_s.update_item(Key={'p': p}, UpdateExpression='REMOVE x.y')
test_table_s.update_item(Key={'p': p}, UpdateExpression='REMOVE x[0]')
# Though in an above test (test_nested_attribute_update_bad_path_dot) we
# showed that DynamoDB does not allow REMOVE x.y if attribute x doesn't
# exist - and generates a ValidationException, if x *does* exist but y
# doesn't, it's fine and the removal should just be silently ignored.
def test_nested_attribute_remove_missing_leaf(test_table_s):
p = random_string()
item = {'p': p, 'a': {'x': 3}, 'b': ['hi']}
test_table_s.put_item(Item=item)
test_table_s.update_item(Key={'p': p}, UpdateExpression='REMOVE a.y')
test_table_s.update_item(Key={'p': p}, UpdateExpression='REMOVE b[7]')
test_table_s.update_item(Key={'p': p}, UpdateExpression='REMOVE c')
# The above UpdateItem calls didn't change anything...
assert test_table_s.get_item(Key={'p': p}, ConsistentRead=True)['Item'] == item
# Similarly for other types of bad paths - using [0] on something which
# doesn't exist or isn't an array.
def test_nested_attribute_update_bad_path_array(test_table_s):