Files
lerobot-clone/src/lerobot/utils/collate.py
Pepijn beb22afd81 review: dedupe regex, centralize column names, harden collate, more tests
* **#2 — dedupe `_PLACEHOLDER_RE`.** The same regex was compiled in
  `recipe.py` and `language_render.py`. Promote to module-level
  `PLACEHOLDER_RE` in `recipe.py` (its primary owner — declares
  template syntax) and import from `language_render.py`.
* **#3 — centralize language column names.** `io_utils.py` had
  hardcoded `{"language_persistent", "language_events"}` literals at
  two sites. Replace with `LANGUAGE_COLUMNS` import so a future column
  rename can't silently desync.
* **#4 — defensive collate preserved-keys.** `lerobot_collate_fn`
  silently filtered language fields from samples that didn't have
  them, which would hand downstream consumers a preserved list
  shorter than the tensor batch. Now: if any sample carries a key,
  every sample in the batch must carry it; otherwise raise a
  `ValueError` so the upstream rendering bug surfaces at the boundary.
* **#5 — `_scalar` rejects non-singleton lists.** Previously a zero-
  or multi-element list fell through and triggered confusing
  `float([])` errors downstream. Now raises `ValueError` with the
  actual length.
* **#6 — refactor `_extract_complementary_data`.** Replace 11 lines
  of `key = {... if ... else {}}` plus an 11-line splat dict with a
  single `_COMPLEMENTARY_KEYS` tuple iterated once.
* **#7 — document `EXTENDED_STYLES`.** Was an empty `set()` with no
  comment. Add a docstring explaining it's an intentional extension
  point: downstream modules append project-local styles before
  `column_for_style` is called.
* **#9 — `tools.mdx` notes the runtime layer is future work.** The
  page referenced `src/lerobot/tools/`, `registry.py`, and
  `get_tools(meta)` — none exist in this PR. Added a callout at the
  start of "How to add your own tool" plus a note on the
  implementations paragraph.
* **#10 — tests for YAML round-trip, malformed rows, blend
  validation.** `test_recipe.py` grew from 1 case to 12 covering:
  blend-or-messages exclusivity, target-turn requirement, blend
  emptiness, weight presence/positivity, nested-blend rejection,
  `from_dict` with nested blends, `from_yaml` / `load_recipe`
  agreement, top-level non-mapping rejection. Added a malformed-row
  test for `_normalize_rows` that asserts non-dict entries raise
  `TypeError`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-06 19:06:38 +02:00

66 lines
2.4 KiB
Python

#!/usr/bin/env python
# Copyright 2026 The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from typing import Any
from torch.utils.data._utils.collate import default_collate
from lerobot.datasets.language import LANGUAGE_COLUMNS
_PYTHON_LIST_KEYS = {"messages", "message_streams", "target_message_indices"}
def lerobot_collate_fn(batch: list[dict[str, Any] | None]) -> dict[str, Any] | None:
"""Collate function that preserves Python-list and language fields as lists.
Drops ``None`` samples (e.g. recipes that yielded no target message), keeps
rendered-message and language fields as plain Python lists, and delegates
every other key to PyTorch's ``default_collate``.
"""
batch = [sample for sample in batch if sample is not None]
if not batch:
return None
# All-or-nothing per key: a partial-presence batch (e.g. half the samples
# carry `messages` and half don't) is a real bug in the upstream
# rendering step — silently filtering would hand downstream consumers a
# preserved list shorter than the tensor batch. Raise instead so the
# mismatch surfaces at the boundary.
preserved: dict[str, list[Any]] = {}
for key in _PYTHON_LIST_KEYS:
presence = [key in sample for sample in batch]
if not any(presence):
continue
if not all(presence):
raise ValueError(
f"Inconsistent batch: {sum(presence)}/{len(batch)} samples carry {key!r}; "
f"every sample in a batch must agree."
)
preserved[key] = [sample[key] for sample in batch]
tensorizable = [
{
key: value
for key, value in sample.items()
if key not in _PYTHON_LIST_KEYS and key not in LANGUAGE_COLUMNS
}
for sample in batch
]
collated = default_collate(tensorizable)
collated.update(preserved)
return collated