JsonObject does not expose array values

[ajrock]

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Environment details

• OS type and version:
• Python version: 3.10
• pip version: 25.2
• google-cloud-spanner version: 3.55.0

Steps to reproduce

1. Have a Json column in Spanner with schema like e.g. {"a": 1, "b": [2,3]}
2. execute SQL selecting field b
3. Attempt to index into the array contained by b
4. error raised

Code example

with my_database.snapshot() as snapshot:
    result = snapshot.execute_sql("SELECT JSON_QUERY(my_json_col, '$."b"') as b_col
isinstance(b_col, google.cloud.spanner_v1.data_types.JsonObject) # True
b_col[0] # raises error 

Stack trace

Traceback (most recent call last):
  File "<string>", line 1, in <module>
KeyError: 0

Basically, I see that holding arrays is seen as possible in JsonObject (

python-spanner/google/cloud/spanner_v1/data_types.py

Line 34 in 9535e5e

self._is_array = len(args) and isinstance(args[0], (list, tuple))

), and is successfully serialized, but you cannot index into it, if you have need to transform the data in code.

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