feat(rust, python): support deserializing struct json into df (pola-r…

…s#9688)

polars/polars-json/src/json/deserialize.rs

@@ -378,21 +378,13 @@ pub(crate) fn _deserialize<'a, A: Borrow<BorrowedValue<'a>>>(
     }
 }
 
-/// Deserializes a `json` [`Value`][Value] into an [`Array`] of [`DataType`]
-/// This is CPU-bounded.
-/// # Error
-/// This function errors iff either:
-/// * `json` is not an [`Array`]
-/// * `data_type` is neither [`DataType::List`] nor [`DataType::LargeList`]
-///
-/// [Value]: simd_json::value::Value
 pub fn deserialize(json: &BorrowedValue, data_type: DataType) -> Result<Box<dyn Array>, Error> {
     match json {
         BorrowedValue::Array(rows) => match data_type {
             DataType::LargeList(inner) => Ok(_deserialize(rows, inner.data_type)),
             _ => todo!("read an Array from a non-Array data type"),
         },
-        _ => todo!("read an Array from a non-Array JSON"),
+        _ => Ok(_deserialize(&[json], data_type)),
     }
 }
 

py-polars/tests/unit/io/test_json.py

@@ -2,6 +2,7 @@
 
 import io
 import json
+import typing
 from typing import TYPE_CHECKING
 
 import pytest
@@ -138,3 +139,18 @@ def test_json_sliced_list_serialization() -> None:
     sliced_df = df[1, :]
     sliced_df.write_ndjson(f)
     assert f.getvalue() == b'{"col1":2,"col2":[6,7,8]}\n'
+
+
+@typing.no_type_check
+def test_json_deserialize_9687() -> None:
+    response = {
+        "volume": [0.0, 0.0, 0.0],
+        "open": [1263.0, 1263.0, 1263.0],
+        "close": [1263.0, 1263.0, 1263.0],
+        "high": [1263.0, 1263.0, 1263.0],
+        "low": [1263.0, 1263.0, 1263.0],
+    }
+
+    assert pl.read_json(json.dumps(response).encode()).to_dict(False) == {
+        k: [v] for k, v in response.items()
+    }