fix: overwrite mode now deletes existing dataset before re-creating

Previously, on_exist="overwrite" called create_dataset directly, which
returned a 409 Conflict (DatasetUploadError) when the dataset already
existed. The code incorrectly assumed Phoenix would create a new version.

The fix looks up the existing dataset, deletes it via the REST API
(DELETE /v1/datasets/{id}), then creates a fresh dataset.

Author: zurfjereluhmie

src/evalwire/uploader.py

@@ -5,6 +5,7 @@
 import logging
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, Literal, cast
+from urllib.parse import quote
 
 import pandas as pd
 
@@ -145,9 +146,12 @@ def _upload_one(
             )
 
         elif on_exist == "overwrite":
-            # Phoenix datasets are versioned; create_dataset with an existing name
-            # adds a new version rather than replacing the dataset object, so a
-            # delete step is not needed (and no delete API exists in Phoenix >=13).
+            try:
+                existing = self.client.datasets.get_dataset(dataset=name)
+                self._delete_dataset(existing.id)
+                logger.info("Deleted existing dataset %r; re-creating.", name)
+            except ValueError:
+                logger.debug("Dataset %r not found; creating it.", name)
             return self.client.datasets.create_dataset(
                 dataframe=df,
                 name=name,
@@ -176,3 +180,15 @@ def _upload_one(
                 input_keys=self.input_keys,
                 output_keys=self.output_keys,
             )
+
+    def _delete_dataset(self, dataset_id: str) -> None:
+        """Delete a dataset via the Phoenix REST API.
+
+        The Phoenix Python client does not expose a delete method, but the
+        server supports ``DELETE /v1/datasets/{id}``.
+        """
+        response = self.client.datasets._client.delete(
+            url=f"v1/datasets/{quote(dataset_id)}",
+            headers={"accept": "application/json"},
+        )
+        response.raise_for_status()

tests/test_uploader.py

@@ -107,19 +107,26 @@ def test_non_not_found_error_propagates(
 
 
 class TestUploadOverwrite:
-    def test_always_calls_upload_dataset(
+    def test_deletes_existing_then_creates(
         self, sample_csv: Path, mock_phoenix_client: MagicMock
     ):
+        existing = MagicMock()
+        existing.id = "ds-123"
+        mock_phoenix_client.datasets.get_dataset.return_value = existing
+        mock_response = MagicMock()
+        mock_phoenix_client.datasets._client.delete.return_value = mock_response
         uploader = _make_uploader(sample_csv, mock_phoenix_client)
         uploader.upload(on_exist="overwrite")
-        assert mock_phoenix_client.datasets.create_dataset.called
+        mock_phoenix_client.datasets._client.delete.assert_called()
+        mock_phoenix_client.datasets.create_dataset.assert_called()
 
-    def test_overwrite_when_dataset_missing_still_creates(
+    def test_creates_directly_when_dataset_missing(
         self, sample_csv: Path, mock_phoenix_client: MagicMock
     ):
         mock_phoenix_client.datasets.get_dataset.side_effect = ValueError("not found")
         uploader = _make_uploader(sample_csv, mock_phoenix_client)
         result = uploader.upload(on_exist="overwrite")
+        mock_phoenix_client.datasets._client.delete.assert_not_called()
         assert mock_phoenix_client.datasets.create_dataset.called
         assert len(result) == 2