test: add missing file error handling for arrow C stream reader

Author: kosiew

python/tests/test_stream_error.py

@@ -0,0 +1,14 @@
+import pyarrow as pa
+import pytest
+
+
+def test_arrow_c_stream_missing_file(ctx, tmp_path):
+    schema = pa.schema([("a", pa.int64())])
+    path = tmp_path / "missing.csv"
+    path.write_text("a\n1\n2\n")
+    df = ctx.read_csv(path, schema=schema)
+    capsule = df.__arrow_c_stream__()
+    path.unlink()
+    reader = pa.RecordBatchReader._import_from_c_capsule(capsule)
+    with pytest.raises(Exception):  # noqa: B017
+        reader.read_all()

src/dataframe.rs

@@ -410,6 +410,12 @@ impl Iterator for PartitionedDataFrameStreamReader {
                     continue;
                 }
                 Err(e) => {
+                    #[cfg(debug_assertions)]
+                    {
+                        log::error!("PartitionedDataFrameStreamReader stream error: {e}");
+                    }
+                    // Stop iteration on error to avoid use-after-free.
+                    self.current = self.streams.len();
                     return Some(Err(ArrowError::ExternalError(Box::new(e))));
                 }
             }