fix(dataset): resolve relative sample files on Windows and filesystem URIs (#4502)

CHANGELOG.md

@@ -33,6 +33,7 @@
 - Bugfix: Native compaction now truncates an oversized tool output before summarizing instead of crashing or silently summarizing an error when it would exceed the model's context window. (#3600)
 - Bugfix: React agent compaction now works after a checkpoint resume — the restored conversation is no longer treated as an always-preserved prefix, so compaction shrinks the context again.
 - Bugfix: Nested `score_reducer` and `task_source` values in serialized task args now restore as instances rather than their registered factories. (#4374)
+- Bugfix: Properly resolve relative sample file paths and file URIs on windows (#4502)
 - Viewer: log listing responses include the log dir's canonical URI (`log_dir_uri`) so the viewer can reliably scope its local cache to the directory.
 - Inspect View: Reuse one warm async S3 client and connection pool across requests — for both log reads and directory listings — instead of creating one per operation, eliminating the per-request credential/connection cold-start (e.g. `/log-headers` ~3s -> ~0.3s, `/logs` ~1.5s -> ~0.06s).
 - Model Roles: `resolve_model_roles` now copies a `Model` passed by object (e.g. via `eval(model_roles=...)`) before stamping its role, so roles supplied through the Python API — not just `--model-role` — get a distinct instance and are not misattributed. (#4464)

src/inspect_ai/dataset/_sources/csv.py

@@ -1,11 +1,10 @@
 import csv
-import os
 from io import TextIOWrapper
 from pathlib import Path
 from typing import Any
 
 from inspect_ai._util.asyncfiles import is_s3_filename
-from inspect_ai._util.file import file
+from inspect_ai._util.file import absolute_file_path, file
 from inspect_ai.dataset._sources.util import resolve_sample_files
 
 from .._dataset import (
@@ -83,7 +82,7 @@ def csv_dataset(
         dataset = MemoryDataset(
             samples=data_to_samples(valid_data, data_to_sample, auto_id),
             name=name,
-            location=os.path.abspath(csv_file),
+            location=absolute_file_path(csv_file),
         )
 
         # resolve relative file paths

src/inspect_ai/dataset/_sources/json.py

@@ -1,13 +1,12 @@
 import json
-import os
 from io import TextIOWrapper
 from pathlib import Path
 from typing import Any
 
 import jsonlines
 
 from inspect_ai._util.asyncfiles import is_s3_filename
-from inspect_ai._util.file import file
+from inspect_ai._util.file import absolute_file_path, file
 
 from .._dataset import (
     Dataset,
@@ -87,7 +86,7 @@ def json_dataset(
                 dataset_reader(f, **reader_kwargs), data_to_sample, auto_id
             ),
             name=name,
-            location=os.path.abspath(json_file),
+            location=absolute_file_path(json_file),
         )
 
         # resolve relative file paths

src/inspect_ai/dataset/_sources/util.py

@@ -7,7 +7,7 @@
     ContentImage,
     ContentVideo,
 )
-from inspect_ai._util.file import filesystem
+from inspect_ai._util.file import dirname, filesystem
 from inspect_ai.model._chat_message import ChatMessage, ChatMessageUser
 from inspect_ai.util._sandbox.environment import SandboxEnvironmentSpec
 
@@ -22,7 +22,7 @@ def resolve_sample_files(dataset: Dataset) -> None:
 
     # filesystem and parent for resolving paths
     fs = filesystem(dataset.location)
-    parent_dir = fs.sep.join(dataset.location.split(fs.sep)[:-1])
+    parent_dir = dirname(dataset.location)
 
     # resolve file locations
     def resolve_file(file: str) -> str:

tests/dataset/test_dataset.py

@@ -8,6 +8,7 @@
 from test_helpers.utils import skip_if_github_action
 
 from inspect_ai._util.content import ContentImage
+from inspect_ai._util.file import exists
 from inspect_ai.dataset import (
     Dataset,
     FieldSpec,
@@ -174,6 +175,21 @@ def test_dataset_image_paths() -> None:
     assert image.exists()
 
 
+def test_dataset_image_paths_file_uri() -> None:
+    # dataset locations that are filesystem URIs should keep their scheme and
+    # still resolve relative sample files against the dataset's parent dir
+    dataset = json_dataset(Path(dataset_path("images.jsonl")).resolve().as_uri())
+    assert dataset.location is not None
+    assert dataset.location.startswith("file://")
+    sample = dataset[0]
+    assert not isinstance(sample.input, str)
+    assert isinstance(sample.input[0], ChatMessageUser)
+    content = sample.input[0].content[1]
+    assert isinstance(content, ContentImage)
+    assert content.image.startswith("file://")
+    assert exists(content.image)
+
+
 def test_dataset_auto_id() -> None:
     dataset = json_dataset(dataset_path("dataset.jsonl"))
     assert all(sample.id is None for sample in dataset)