empty_json_to_empty_df

pola-rs · Sep 19, 2024 · 7092f3b · 7092f3b
1 parent 9384945
commit 7092f3b
Show file tree

Hide file tree

Showing 2 changed files with 18 additions and 1 deletion.
diff --git a/crates/polars-io/src/json/mod.rs b/crates/polars-io/src/json/mod.rs
@@ -281,7 +281,14 @@ where
                 } else {
                     simd_json::to_borrowed_value(owned).map_err(to_compute_err)?
                 };
-
+                match &json_value {
+                    BorrowedValue::Array(array) => {
+                        if array.is_empty() {
+                            return Ok(DataFrame::empty());
+                        }
+                    },
+                    _ => {},
+                }
                 // struct type
                 let dtype = if let Some(mut schema) = self.schema {
                     if let Some(overwrite) = self.schema_overwrite {

diff --git a/py-polars/tests/unit/io/test_json.py b/py-polars/tests/unit/io/test_json.py
@@ -420,3 +420,13 @@ def test_compressed_json() -> None:
     uncompressed = io.BytesIO(json_bytes)
     out = pl.read_json(uncompressed)
     assert_frame_equal(out, expected)
+
+
+def test_empty_list_json() -> None:
+    df = pl.read_json(io.StringIO("[]"))
+    assert df.shape == (0, 0)
+    assert isinstance(df, pl.DataFrame)
+
+    df = pl.read_json(b"[]")
+    assert df.shape == (0, 0)
+    assert isinstance(df, pl.DataFrame)