[BUG] TensorClass.get(..., default) not propagated

[egorchakov]

Describe the bug

When calling .get() on a @tensorclass with TensorDict attributes, the default kwarg does not seem to be propagated properly.

To Reproduce

# file: tensorclass_get_default.py
# /// script
# requires-python = "==3.12"
# dependencies = [
#     "tensordict==0.6.2",
#     "packaging",
# ]
# ///

from tensordict import TensorDict, tensorclass


@tensorclass
class Data:
    td: TensorDict


Data(td=TensorDict({})).get(("td", "missing"), default=None)

❯ : uv run tensorclass_get_default.py
Reading inline script metadata from `tensorclass_get_default.py`
Traceback (most recent call last):
  File "[...]/tensorclass_get_default.py", line 18, in <module>
    Data(td=TensorDict({})).get(("td", "missing"), default=None)
  File "/home/evgenii/.cache/uv/archive-v0/yCPXuVvMie1NN0uqK0b3L/lib/python3.12/site-packages/tensordict/tensorclass.py", line 1792, in _get
    return getattr(self, key[0]).get(key[1:])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/evgenii/.cache/uv/archive-v0/yCPXuVvMie1NN0uqK0b3L/lib/python3.12/site-packages/tensordict/base.py", line 5044, in get
    return self._get_tuple(key, default=default)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/evgenii/.cache/uv/archive-v0/yCPXuVvMie1NN0uqK0b3L/lib/python3.12/site-packages/tensordict/_td.py", line 2468, in _get_tuple
    first = self._get_str(key[0], default)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/evgenii/.cache/uv/archive-v0/yCPXuVvMie1NN0uqK0b3L/lib/python3.12/site-packages/tensordict/_td.py", line 2464, in _get_str
    return self._default_get(first_key, default)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/evgenii/.cache/uv/archive-v0/yCPXuVvMie1NN0uqK0b3L/lib/python3.12/site-packages/tensordict/base.py", line 4995, in _default_get
    raise KeyError(
KeyError: 'key "missing" not found in TensorDict with keys []'

Expected behavior

The default kwarg is propagated as if on a nested TensorDict.

System info

0.6.2 2.2.2 3.12.0 (main, Oct  3 2023, 01:27:23) [Clang 17.0.1 ] linux 2.6.0+cu124

Reason and Possible fixes

tensordict.set_get_defaults_to_none(True) fixes this if we want the default to be None specifically.

Checklist

• I have checked that there is no similar issue in the repo (required)
• I have read the documentation (required)
• I have provided a minimal working example to reproduce the bug (required)

[vmoens]

I fail to reprod on nightlies so closing
the new release will be out today (hopefully)

[egorchakov]

@vmoens It seems in v0.7.0 the returned value isNone rather than the specified default one:

# file: tensorclass_get_default.py
# /// script
# requires-python = "==3.12"
# dependencies = [
#     "tensordict==0.7.0",
# ]
# ///

from tensordict import TensorClass, TensorDict


class Data(TensorClass):
    td: TensorDict


assert Data(td=TensorDict({})).get(("td", "missing"), default=0) == 0

❯ : uv run tensorclass_get_default.py
Traceback (most recent call last):
  File "[...]/tensorclass_get_default.py", line 16, in <module>
    assert Data(td=TensorDict({})).get(("td", "missing"), default=0) == 0
AssertionError

[vmoens]

This is really bad :/
I will make a minor with the fix

[vmoens]

(in the meantime feel free to use data.key0.get(key[1:], default))

[vmoens]

Solved by #1211