ROLLOUT 2 · narwhals-dev/narwhals
narwhals-dev__narwhals-2864
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11model calls
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System instructions 4,822 characters
You are a principal Python software engineer resolving a repository issue in `/workspace`. Your sole objective is to produce a minimal, root-cause source patch that passes every hidden fail-to-pass and pass-to-pass regression test on the first grading run. ## Critical Environment & Grader Rules 1. **Air-Gapped Sandbox & Available CLI Tools**: No network access. Never run `pip`, `uv`, `conda`, or `git fetch`. Note: `rg` (`ripgrep`) is NOT installed in the container — always use `grep -rn --include="*.py"` for fast exact searches so you never waste a tool call on `command not found`. 2. **Protected Grading Paths**: Before running official verification, the grading harness **strips and reverts all changes** to `tests/`, `test/`, `testing/`, `test_*.py`, `*_test.py`, `conftest.py`, `pyproject.toml`, `setup.cfg`, `pytest.ini`, and `tox.ini`. Every part of your fix MUST reside in non-test production source files. 3. **Untracked File Trap (`git add -N .`)**: `submit_patch` stages ALL untracked files inside `/workspace`! Never leave reproduction or scratch files inside `/workspace` — run reproductions inline via `python3 - <<'PY'` or inside `/tmp/repro.py` in a single `run_command`. 4. **Stdout Truncation Rule**: `run_command` truncates stdout after the first 5,000 characters from the TOP. Always run pytest quietly with short tracebacks: `pytest path/to/test_file.py -k pattern -q --tb=short --no-header` If a test file is large, redirect output to `/tmp/pytest.log` and inspect `tail -n 80 /tmp/pytest.log` so failure tracebacks at the bottom are never cut off. 5. **Strict Pacing Discipline**: `get_status` and `submit_patch` are free and do NOT count toward `max_tool_calls`. Target **16-22 counted tool calls total**, and **begin your first `edit_file` change no later than tool call 15**. Reserve at least 4 calls for verification, `git status --short && git diff`, and submission. ## Execution Protocol ### Phase 1 — Pinpoint Code & Tests Immediately (1-2 tool calls) - The user message already contains `Workspace Layout` — do NOT waste a turn running `ls` on top-level directories. - Run a single compound `run_command` with `grep -rn --include="*.py"` to locate: (a) the exact symbols, error strings, or functions from the problem description, (b) **all parallel or sibling implementations** (for example sync + async variants, `Client` + `AsyncClient`, serializer + deserializer, multiple backends/dialects, base + subclass methods, `__init__.py` / `__all__` exports), and (c) the closest existing unit test files under `tests/`. ### Phase 2 — Deep Read & Spec Anchor (2-5 tool calls) - Use `read_file` with generous `start_line` and `end_line` windows (180-300 lines per call so you read whole modules in fewer calls) on the target function/class, callers, type annotations, and neighboring tests. - Before editing, verify every explicit and implicit requirement from the issue: exact parameter names, defaults, boundary/domain edge cases, exception types/messages, `None` vs empty collection vs falsy (`0`, `False`, `""`) semantics, mutability/copying, and return types. ### Phase 3 — Reproduce Bug in One Call (1 tool call) - Run ONE concise command (`python3 - <<'PY' ... PY` or targeted `pytest ... -q --tb=short --no-header`) via `run_command` to observe the exact pre-fix failure. Do NOT spend multiple tool calls writing separate reproduction scripts. ### Phase 4 — Surgical Implementation Across All Parallel Paths (1-4 tool calls) - Begin editing by tool call 15! Use `edit_file` with 4-6 lines of exact surrounding context copied from `read_file`. - Update ALL parallel codepaths (sync/async, multiple classes/dialects, type hints) consistently so partial fixes do not fail sibling tests. - **2-Strike Edit Rule**: If `edit_file` fails twice on the same block due to whitespace or escaping, do not retry `edit_file` a third time — apply an atomic Python transformation via `run_command` and immediately verify `python3 -m py_compile path/to/file.py`. ### Phase 5 — Edge-Case Verification, Diff Hygiene & Clean Exit (2-4 tool calls) - Run a single compound `run_command` testing both your reproduction + boundary edge cases (`None`, empty input, leading/trailing delimiters, subdomain/prefix boundaries, subclass/async parity) AND the relevant existing `pytest` module(s) with `-q --tb=short --no-header`. - Run `git status --short && git diff` via `run_command`. Confirm: - ZERO untracked (`??`) files in `/workspace` (`rm -f` any untracked workspace files immediately), - ZERO modifications to `tests/` or protected config files (`git checkout -- tests/` if touched), - Minimal, clean diff with valid imports and indentation. - Call `submit_patch` once verification passes, then respond with a brief 2-sentence plain-text summary and make NO further tool calls.
Task prompt 7,523 characters
You are evaluating a software engineering task for repository narwhals-dev/narwhals.
Problem Statement:
bug: `ArrowSeries.scatter` raises out of bound error
pyarrow backed series raises an out of bound error in scatter if `indices`:
- is not 0
- are not full length of the series
Repro:
```py
import narwhals as nw
import pyarrow as pa
tbl = pa.table({"a": [1, 2, 3], "b": [142, 124, 132]})
frame = nw.from_native(tbl, eager_only=True)
ser = frame["a"]
try:
result = ser.scatter(1, 999)
except Exception as exc:
print(exc)
try:
result = ser.scatter([0, 2], [999, 888])
except Exception as exc:
print(exc)
```
> Index 1 out of bounds
> Index 2 out of bounds
## Task Budget (Session terminates when any budget is exhausted)
- Time allowance: 7.5 minutes
- Tool calls allowance: 30 calls
- Max loop iterations: 40 turns
## Execution Environment Rules
- Single command timeout: 90 seconds (commands exceeding this fail without ending the session)
- Command output limit: 5000 characters
- File view limit: 150 lines per read_file call
- File character limit: 10000 characters per read_file call
- Environment is offline (no network/PyPI access). All repository and test dependencies are ALREADY pre-installed. Do NOT attempt to run pip install or download packages.
## Instructions:
0. All source code is under `/workspace`. Do NOT search outside `/workspace` (e.g. `/usr/`, `/wheels/`, system site-packages). If imports fail, the issue is in the source code under `/workspace`, not in missing system packages.
1. Analyze the problem statement and any provided hints carefully to identify all requested script paths, CLI subcommands, or Python modules.
2. Inspect existing codebase conventions and test files before making edits.
3. Verify your implementation using targeted tests or inline assertions before submitting.
4. Call submit_patch only after your implementation is complete and verified.
5. As your final action, you must return a text-only response reporting your completion to terminate the session.
## Workspace Layout
The repository is located at `/workspace`. Here is the directory tree (up to 3 levels):
```
./CONTRIBUTING.md
./LICENSE.md
./Makefile
./README.md
./docs
./docstring_template.mustache
./mkdocs.yml
./narwhals
./narwhals/__init__.py
./narwhals/_arrow
./narwhals/_arrow/__init__.py
./narwhals/_arrow/dataframe.py
./narwhals/_arrow/expr.py
./narwhals/_arrow/group_by.py
./narwhals/_arrow/namespace.py
./narwhals/_arrow/selectors.py
./narwhals/_arrow/series.py
./narwhals/_arrow/series_cat.py
./narwhals/_arrow/series_dt.py
./narwhals/_arrow/series_list.py
./narwhals/_arrow/series_str.py
./narwhals/_arrow/series_struct.py
./narwhals/_arrow/typing.py
./narwhals/_arrow/utils.py
./narwhals/_compliant
./narwhals/_compliant/__init__.py
./narwhals/_compliant/any_namespace.py
./narwhals/_compliant/dataframe.py
./narwhals/_compliant/expr.py
./narwhals/_compliant/group_by.py
./narwhals/_compliant/namespace.py
./narwhals/_compliant/selectors.py
./narwhals/_compliant/series.py
./narwhals/_compliant/typing.py
./narwhals/_compliant/when_then.py
./narwhals/_compliant/window.py
./narwhals/_constants.py
./narwhals/_dask
./narwhals/_dask/__init__.py
./narwhals/_dask/dataframe.py
./narwhals/_dask/expr.py
./narwhals/_dask/expr_dt.py
./narwhals/_dask/expr_str.py
./narwhals/_dask/group_by.py
./narwhals/_dask/namespace.py
./narwhals/_dask/selectors.py
./narwhals/_dask/utils.py
./narwhals/_duckdb
./narwhals/_duckdb/__init__.py
./narwhals/_duckdb/dataframe.py
./narwhals/_duckdb/expr.py
./narwhals/_duckdb/expr_dt.py
./narwhals/_duckdb/expr_list.py
./narwhals/_duckdb/expr_str.py
./narwhals/_duckdb/expr_struct.py
./narwhals/_duckdb/group_by.py
./narwhals/_duckdb/namespace.py
./narwhals/_duckdb/selectors.py
./narwhals/_duckdb/series.py
./narwhals/_duckdb/typing.py
./narwhals/_duckdb/utils.py
./narwhals/_duration.py
./narwhals/_enum.py
./narwhals/_expression_parsing.py
./narwhals/_ibis
./narwhals/_ibis/__init__.py
./narwhals/_ibis/dataframe.py
./narwhals/_ibis/expr.py
./narwhals/_ibis/expr_dt.py
./narwhals/_ibis/expr_list.py
./narwhals/_ibis/expr_str.py
./narwhals/_ibis/expr_struct.py
./narwhals/_ibis/group_by.py
./narwhals/_ibis/namespace.py
./narwhals/_ibis/selectors.py
./narwhals/_ibis/series.py
./narwhals/_ibis/utils.py
./narwhals/_interchange
./narwhals/_interchange/__init__.py
./narwhals/_interchange/dataframe.py
./narwhals/_interchange/series.py
./narwhals/_namespace.py
./narwhals/_pandas_like
./narwhals/_pandas_like/__init__.py
./narwhals/_pandas_like/dataframe.py
./narwhals/_pandas_like/expr.py
./narwhals/_pandas_like/group_by.py
./narwhals/_pandas_like/namespace.py
./narwhals/_pandas_like/selectors.py
./narwhals/_pandas_like/series.py
./narwhals/_pandas_like/series_cat.py
./narwhals/_pandas_like/series_dt.py
./narwhals/_pandas_like/series_list.py
./narwhals/_pandas_like/series_str.py
./narwhals/_pandas_like/series_struct.py
./narwhals/_pandas_like/typing.py
./narwhals/_pandas_like/utils.py
./narwhals/_polars
./narwhals/_polars/__init__.py
./narwhals/_polars/dataframe.py
./narwhals/_polars/expr.py
./narwhals/_polars/group_by.py
./narwhals/_polars/namespace.py
./narwhals/_polars/series.py
./narwhals/_polars/typing.py
./narwhals/_polars/utils.py
./narwhals/_spark_like
./narwhals/_spark_like/__init__.py
./narwhals/_spark_like/dataframe.py
./narwhals/_spark_like/expr.py
./narwhals/_spark_like/expr_dt.py
./narwhals/_spark_like/expr_list.py
./narwhals/_spark_like/expr_str.py
./narwhals/_spark_like/expr_struct.py
./narwhals/_spark_like/group_by.py
./narwhals/_spark_like/namespace.py
./narwhals/_spark_like/selectors.py
./narwhals/_spark_like/utils.py
./narwhals/_sql
./narwhals/_sql/__init__.py
./narwhals/_sql/dataframe.py
./narwhals/_sql/expr.py
./narwhals/_sql/group_by.py
./narwhals/_sql/typing.py
./narwhals/_sql/when_then.py
./narwhals/_translate.py
./narwhals/_typing_compat.py
./narwhals/_utils.py
./narwhals/dataframe.py
./narwhals/dependencies.py
./narwhals/dtypes.py
./narwhals/exceptions.py
./narwhals/expr.py
./narwhals/expr_cat.py
./narwhals/expr_dt.py
./narwhals/expr_list.py
./narwhals/expr_name.py
./narwhals/expr_str.py
./narwhals/expr_struct.py
./narwhals/functions.py
./narwhals/group_by.py
./narwhals/py.typed
./narwhals/schema.py
./narwhals/selectors.py
./narwhals/series.py
./narwhals/series_cat.py
./narwhals/series_dt.py
./narwhals/series_list.py
./narwhals/series_str.py
./narwhals/series_struct.py
./narwhals/stable
./narwhals/stable/__init__.py
./narwhals/stable/v1
./narwhals/this.py
./narwhals/translate.py
./narwhals/typing.py
./narwhals/utils.py
./noxfile.py
./pyproject.toml
./tests
./tpch
./tpch/README.md
./tpch/__init__.py
./tpch/execute.py
./tpch/generate_data.py
./tpch/queries
./tpch/queries/__init__.py
./tpch/queries/q1.py
./tpch/queries/q10.py
./tpch/queries/q11.py
./tpch/queries/q12.py
./tpch/queries/q13.py
./tpch/queries/q14.py
./tpch/queries/q15.py
./tpch/queries/q16.py
./tpch/queries/q17.py
./tpch/queries/q18.py
./tpch/queries/q19.py
./tpch/queries/q2.py
./tpch/queries/q20.py
./tpch/queries/q21.py
./tpch/queries/q22.py
./tpch/queries/q3.py
./tpch/queries/q4.py
./tpch/queries/q5.py
./tpch/queries/q6.py
./tpch/queries/q7.py
./tpch/tests
./utils
./utils/__init__.py
./utils/api-completeness.md.jinja
./utils/bump_version.py
./utils/check_api_reference.py
./utils/check_dist_content.py
./utils/check_docstrings.py
./utils/check_for_no_build_errors.py
./utils/generate_backend_completeness.py
./utils/generate_random_versions.py
./utils/generate_zen_content.py
./utils/import_check.py
```
Turn 1at 21 s261 tokens out4,792 prompt tokens
The user is reporting a bug in `ArrowSeries.scatter` where it raises an "out of bound" error when `indices` is not 0 and is not the full length of the series. Let's start by reproducing the bug.
TOOL CALL · run_command
{
"command": "python3 - <<'PY'\nimport narwhals as nw\nimport pyarrow as pa\n\ntbl = pa.table({\"a\": [1, 2, 3], \"b\": [142, 124, 132]})\nframe = nw.from_native(tbl, eager_only=True)\nser = frame[\"a\"]\n\ntry:\n print(\"Testing single index scatter...\")\n result = ser.scatter(1, 999)\n print(\"Result:\", result)\nexcept Exception as exc:\n print(\"Caught exception:\", exc)\n\ntry:\n print(\"\\nTesting multiple indices scatter...\")\n result = ser.scatter([0, 2], [999, 888])\n print(\"Result:\", result)\nexcept Exception as exc:\n print(\"Caught exception:\", exc)\nPY\n"
}Result of run_command 214 characters
{
"status": "ok",
"stdout": "Testing single index scatter...\nCaught exception: Index 1 out of bounds\n\nTesting multiple indices scatter...\nCaught exception: Index 2 out of bounds\n",
"stderr": "",
"exit_code": 0
}Generated tokens 261 tokens · stopped: STOP
<|channel>thought
The user is reporting a bug in `ArrowSeries.scatter` where it raises an "out of bound" error when `indices` is not 0 and is not the full length of the series.
Let's start by reproducing the bug.<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY'
import narwhals as nw
import pyarrow as pa
tbl = pa.table({"a": [1, 2, 3], "b": [142, 124, 132]})
frame = nw.from_native(tbl, eager_only=True)
ser = frame["a"]
try:
print("Testing single index scatter...")
result = ser.scatter(1, 999)
print("Result:", result)
except Exception as exc:
print("Caught exception:", exc)
try:
print("\nTesting multiple indices scatter...")
result = ser.scatter([0, 2], [999, 888])
print("Result:", result)
except Exception as exc:
print("Caught exception:", exc)
PY
<|"|>}<tool_call|><|tool_response>
Turn 2at 31 s78 tokens out5,128 prompt tokens
The bug is reproduced. Now I need to find where `scatter` is implemented for Arrow-backed series. I'll search for `scatter` in `narwhals/_arrow/series.py` and other potential locations.
TOOL CALL · run_command
{
"command": "grep -rn \"scatter\" narwhals/_arrow/series.py"
}Result of run_command 139 characters
{
"status": "ok",
"stdout": "440: def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\n",
"stderr": "",
"exit_code": 0
}Generated tokens 78 tokens · stopped: STOP
The bug is reproduced. Now I need to find where `scatter` is implemented for Arrow-backed series.
I'll search for `scatter` in `narwhals/_arrow/series.py` and other potential locations.<channel|><|tool_call>call:run_command{command:<|"|>grep -rn "scatter" narwhals/_arrow/series.py<|"|>}<tool_call|><|tool_response>
Turn 3at 38 s82 tokens out5,271 prompt tokens
Okay, `scatter` is defined in `narwhals/_arrow/series.py` at line 440. Let's examine the implementation of `scatter` in `narwhals/_arrow/series.py`.
TOOL CALL · read_file
{
"filepath": "narwhals/_arrow/series.py",
"start_line": 440
}Result of read_file 6,150 characters
{
"status": "ok",
"filepath": "narwhals/_arrow/series.py",
"content": " def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\n import numpy as np # ignore-banned-import\n\n values_native: ArrayAny\n if isinstance(indices, int):\n indices_native = pa.array([indices])\n values_native = pa.array([values])\n else:\n # TODO(unassigned): we may also want to let `indices` be a Series.\n # https://github.com/narwhals-dev/narwhals/issues/2155\n indices_native = pa.array(indices)\n if isinstance(values, self.__class__):\n values_native = values.native.combine_chunks()\n else:\n # NOTE: Requires fixes in https://github.com/zen-xu/pyarrow-stubs/pull/209\n pa_array: Incomplete = pa.array\n values_native = pa_array(values)\n\n sorting_indices = pc.sort_indices(indices_native)\n indices_native = indices_native.take(sorting_indices)\n values_native = values_native.take(sorting_indices)\n\n mask: _1DArray = np.zeros(self.len(), dtype=bool)\n mask[indices_native] = True\n # NOTE: Multiple issues\n # - Missing `values` type\n # - `mask` accepts a `np.ndarray`, but not mentioned in stubs\n # - Missing `replacements` type\n # - Missing return type\n pc_replace_with_mask: Incomplete = pc.replace_with_mask\n return self._with_native(\n pc_replace_with_mask(self.native, mask, values_native.take(indices_native))\n )\n\n def to_list(self) -> list[Any]:\n return self.native.to_pylist()\n\n def __array__(self, dtype: Any = None, *, copy: bool | None = None) -> _1DArray:\n return self.native.__array__(dtype=dtype, copy=copy)\n\n def to_numpy(self, dtype: Any = None, *, copy: bool | None = None) -> _1DArray:\n return self.native.to_numpy()\n\n def alias(self, name: str) -> Self:\n result = self.__class__(self.native, name=name, version=self._version)\n result._broadcast = self._broadcast\n return result\n\n @property\n def dtype(self) -> DType:\n return native_to_narwhals_dtype(self.native.type, self._version)\n\n def abs(self) -> Self:\n return self._with_native(pc.abs(self.native))\n\n def cum_sum(self, *, reverse: bool) -> Self:\n cum_sum = pc.cumulative_sum\n result = (\n cum_sum(self.native, skip_nulls=True)\n if not reverse\n else cum_sum(self.native[::-1], skip_nulls=True)[::-1]\n )\n return self._with_native(result)\n\n def round(self, decimals: int) -> Self:\n return self._with_native(\n pc.round(self.native, decimals, round_mode=\"half_towards_infinity\")\n )\n\n def diff(self) -> Self:\n return self._with_native(pc.pairwise_diff(self.native.combine_chunks()))\n\n def any(self, *, _return_py_scalar: bool = True) -> bool:\n return maybe_extract_py_scalar(\n pc.any(self.native, min_count=0), _return_py_scalar\n )\n\n def all(self, *, _return_py_scalar: bool = True) -> bool:\n return maybe_extract_py_scalar(\n pc.all(self.native, min_count=0), _return_py_scalar\n )\n\n def is_between(\n self, lower_bound: Any, upper_bound: Any, closed: ClosedInterval\n ) -> Self:\n _, lower_bound = extract_native(self, lower_bound)\n _, upper_bound = extract_native(self, upper_bound)\n if closed == \"left\":\n ge = pc.greater_equal(self.native, lower_bound)\n lt = pc.less(self.native, upper_bound)\n res = pc.and_kleene(ge, lt)\n elif closed == \"right\":\n gt = pc.greater(self.native, lower_bound)\n le = pc.less_equal(self.native, upper_bound)\n res = pc.and_kleene(gt, le)\n elif closed == \"none\":\n gt = pc.greater(self.native, lower_bound)\n lt = pc.less(self.native, upper_bound)\n res = pc.and_kleene(gt, lt)\n elif closed == \"both\":\n ge = pc.greater_equal(self.native, lower_bound)\n le = pc.less_equal(self.native, upper_bound)\n res = pc.and_kleene(ge, le)\n else:\n assert_never(closed)\n return self._with_native(res)\n\n def is_null(self) -> Self:\n return self._with_native(self.native.is_null(), preserve_broadcast=True)\n\n def is_nan(self) -> Self:\n return self._with_native(pc.is_nan(self.native), preserve_broadcast=True)\n\n def cast(self, dtype: IntoDType) -> Self:\n data_type = narwhals_to_native_dtype(dtype, self._version)\n return self._with_native(pc.cast(self.native, data_type), preserve_broadcast=True)\n\n def null_count(self, *, _return_py_scalar: bool = True) -> int:\n return maybe_extract_py_scalar(self.native.null_count, _return_py_scalar)\n\n def head(self, n: int) -> Self:\n if n >= 0:\n return self._with_native(self.native.slice(0, n))\n else:\n num_rows = len(self)\n return self._with_native(self.native.slice(0, max(0, num_rows + n)))\n\n def tail(self, n: int) -> Self:\n if n >= 0:\n num_rows = len(self)\n return self._with_native(self.native.slice(max(0, num_rows - n)))\n else:\n return self._with_native(self.native.slice(abs(n)))\n\n def is_in(self, other: Any) -> Self:\n if self._is_native(other):\n value_set: ArrayOrChunkedArray = other\n else:\n value_set = pa.array(other)\n return self._with_native(pc.is_in(self.native, value_set=value_set))\n\n def arg_true(self) -> Self:\n import numpy as np # ignore-banned-import\n\n res = np.flatnonzero(self.native)\n return self.from_iterable(res, name=self.name, context=self)\n\n def item(self, index: int | None = None) -> Any:\n if index is None:\n if len(self) != 1:",
"start_line": 440,
"end_line": 589,
"total_lines": 1170,
"is_truncated": true
}Generated tokens 82 tokens · stopped: STOP
Okay, `scatter` is defined in `narwhals/_arrow/series.py` at line 440.
Let's examine the implementation of `scatter` in `narwhals/_arrow/series.py`.
<channel|><|tool_call>call:read_file{filepath:<|"|>narwhals/_arrow/series.py<|"|>,start_line:440}<tool_call|><|tool_response>
Turn 4at 130 s1,558 tokens out7,287 prompt tokens
Here is the code for `scatter`:
```python
def scatter(self, indices: int | Sequence[int], values: Any) -> Self:
import numpy as np # ignore-banned-import
values_native: ArrayAny
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
# TODO(unassigned): we may also want to let `indices` be a Series.
# https://github.com/narwhals-dev/narwhals/issues/2155
indices_native = pa.array(indices)
if isinstance(values, self.__class__):
values_native = values.native.combine_chunks()
else:
# NOTE: Requires fixes in https://github.com/zen-xu/pyarrow-stubs/pull/209
pa_array: Incomplete = pa.array
values_native = pa_array(values)
sorting_indices = pc.sort_indices(indices_native)
indices_native = indices_native.take(sorting_indices)
values_native = values_native.take(sorting_indices)
mask: _1DArray = np.zeros(self.len(), dtype=bool)
mask[indices_native] = True
# NOTE: Multiple issues
# - Missing `values` type
# - `mask` accepts a `np.ndarray`, but not mentioned in stubs
# - Missing `replacements` type
# - Missing return type
pc_replace_with_mask: Incomplete = pc.replace_with_mask
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
)
```
Wait, look at this line:
`pc_replace_with_mask(self.native, mask, values_native.take(indices_native))`
`indices_native` is a pyarrow array of indices.
`values_native.take(indices_native)` will take elements from `values_native` at positions specified by `indices_native`.
But `values_native` already has the same length as `indices_native` (it's built from `values` which might be a scalar or a sequence of the same length as `indices`).
Wait, let's re-read the construction of `values_native`:
```python
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
indices_native = pa.array(indices)
if isinstance(values, self.__class__):
values_native = values.native.combine_chunks()
else:
pa_array: Incomplete = pa.array
values_native = pa_array(values)
```
If `indices` is `[0, 2]` and `values` is `[999, 888]`, then `indices_native` is `[0, 2]` and `values_native` is `[999, 888]`.
Then:
```python
sorting_indices = pc.sort_indices(indices_native)
indices_native = indices_native.take(sorting_indices)
values_native = values_native.take(sorting_indices)
```
If `indices` was `[0, 2]`, `sorting_indices` is `[0, 1]`. `indices_native` stays `[0, 2]`, `values_native` stays `[999, 888]`.
Then:
```python
mask: _1DArray = np.zeros(self.len(), dtype=bool)
mask[indices_native] = True
```
This works if `indices_native` is a pyarrow array and `mask` is a numpy array. Pyarrow arrays can be used as indices for numpy arrays.
But then:
```python
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
)
```
Here `values_native.take(indices_native)` is called.
`values_native` is `[999, 888]`.
`indices_native` is `[0, 2]`.
`values_native.take([0, 2])` will try to take elements at index 0 and index 2 from `values_native`.
But `values_native` only has 2 elements (indices 0 and 1).
So it raises an "out of bounds" error for index 2.
The bug is exactly here: `values_native.take(indices_native)`.
It should probably just be `values_native`.
Wait, why was `.take(indices_native)` there in the first place?
If `indices` are `[0, 2]` and `values` are `[999, 888]`, then `values_native` is `[999, 888]`.
`pc_replace_with_mask(self.native, mask, values_native)` will replace values in `self.native` where `mask` is true (i.e. at indices 0 and 2) using values from `values_native` (indices 0 and 1).
Let's verify this.
`pc.replace_with_mask(array, mask, replacements)`:
The `replacements` array must be the same length as the `mask` array? Or the same length as the number of true values in the mask?
According to pyarrow documentation for `replace_with_mask`:
> replacements: Array. The values to replace with where mask is true. Must be the same length as mask.
Wait, if `replacements` must be the same length as `mask`, then `values_native` (which has the length of `indices`) is not enough.
Let's check pyarrow documentation or try it:
TOOL CALL · run_command
{
"command": "python3 - <<'PY'\nimport pyarrow as pa\nimport pyarrow.compute as pc\nimport numpy as np\n\narr = pa.array([1, 2, 3])\nmask = np.array([True, False, True])\nreplacements = pa.array([999, 888])\ntry:\n print(pc.replace_with_mask(arr, mask, replacements))\nexcept Exception as e:\n print(e)\n\nreplacements_full = pa.array([999, 0, 888])\nprint(pc.replace_with_mask(arr, mask, replacements_full))\nPY\n"
}Result of run_command 112 characters
{
"status": "ok",
"stdout": "[\n 999,\n 2,\n 888\n]\n[\n 999,\n 2,\n 0\n]\n",
"stderr": "",
"exit_code": 0
}Generated tokens 1,558 tokens · stopped: STOP
Here is the code for `scatter`:
```python
def scatter(self, indices: int | Sequence[int], values: Any) -> Self:
import numpy as np # ignore-banned-import
values_native: ArrayAny
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
# TODO(unassigned): we may also want to let `indices` be a Series.
# https://github.com/narwhals-dev/narwhals/issues/2155
indices_native = pa.array(indices)
if isinstance(values, self.__class__):
values_native = values.native.combine_chunks()
else:
# NOTE: Requires fixes in https://github.com/zen-xu/pyarrow-stubs/pull/209
pa_array: Incomplete = pa.array
values_native = pa_array(values)
sorting_indices = pc.sort_indices(indices_native)
indices_native = indices_native.take(sorting_indices)
values_native = values_native.take(sorting_indices)
mask: _1DArray = np.zeros(self.len(), dtype=bool)
mask[indices_native] = True
# NOTE: Multiple issues
# - Missing `values` type
# - `mask` accepts a `np.ndarray`, but not mentioned in stubs
# - Missing `replacements` type
# - Missing return type
pc_replace_with_mask: Incomplete = pc.replace_with_mask
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
)
```
Wait, look at this line:
`pc_replace_with_mask(self.native, mask, values_native.take(indices_native))`
`indices_native` is a pyarrow array of indices.
`values_native.take(indices_native)` will take elements from `values_native` at positions specified by `indices_native`.
But `values_native` already has the same length as `indices_native` (it's built from `values` which might be a scalar or a sequence of the same length as `indices`).
Wait, let's re-read the construction of `values_native`:
```python
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
indices_native = pa.array(indices)
if isinstance(values, self.__class__):
values_native = values.native.combine_chunks()
else:
pa_array: Incomplete = pa.array
values_native = pa_array(values)
```
If `indices` is `[0, 2]` and `values` is `[999, 888]`, then `indices_native` is `[0, 2]` and `values_native` is `[999, 888]`.
Then:
```python
sorting_indices = pc.sort_indices(indices_native)
indices_native = indices_native.take(sorting_indices)
values_native = values_native.take(sorting_indices)
```
If `indices` was `[0, 2]`, `sorting_indices` is `[0, 1]`. `indices_native` stays `[0, 2]`, `values_native` stays `[999, 888]`.
Then:
```python
mask: _1DArray = np.zeros(self.len(), dtype=bool)
mask[indices_native] = True
```
This works if `indices_native` is a pyarrow array and `mask` is a numpy array. Pyarrow arrays can be used as indices for numpy arrays.
But then:
```python
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
)
```
Here `values_native.take(indices_native)` is called.
`values_native` is `[999, 888]`.
`indices_native` is `[0, 2]`.
`values_native.take([0, 2])` will try to take elements at index 0 and index 2 from `values_native`.
But `values_native` only has 2 elements (indices 0 and 1).
So it raises an "out of bounds" error for index 2.
The bug is exactly here: `values_native.take(indices_native)`.
It should probably just be `values_native`.
Wait, why was `.take(indices_native)` there in the first place?
If `indices` are `[0, 2]` and `values` are `[999, 888]`, then `values_native` is `[999, 888]`.
`pc_replace_with_mask(self.native, mask, values_native)` will replace values in `self.native` where `mask` is true (i.e. at indices 0 and 2) using values from `values_native` (indices 0 and 1).
Let's verify this.
`pc.replace_with_mask(array, mask, replacements)`:
The `replacements` array must be the same length as the `mask` array? Or the same length as the number of true values in the mask?
According to pyarrow documentation for `replace_with_mask`:
> replacements: Array. The values to replace with where mask is true. Must be the same length as mask.
Wait, if `replacements` must be the same length as `mask`, then `values_native` (which has the length of `indices`) is not enough.
Let's check pyarrow documentation or try it:
<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY'
import pyarrow as pa
import pyarrow.compute as pc
import numpy as np
arr = pa.array([1, 2, 3])
mask = np.array([True, False, True])
replacements = pa.array([999, 888])
try:
print(pc.replace_with_mask(arr, mask, replacements))
except Exception as e:
print(e)
replacements_full = pa.array([999, 0, 888])
print(pc.replace_with_mask(arr, mask, replacements_full))
PY
<|"|>}<tool_call|><|tool_response>
Turn 5at 210 s1,183 tokens out8,921 prompt tokens
Wait! My test showed:
```
[
999,
2,
888
]
```
When `replacements` was `[999, 888]` and `mask` was `[True, False, True]`.
That's 2 replacements and 2 True in mask.
So `replacements` does NOT have to be the same length as `mask`. It can be the same length as the number of True values in the mask.
Wait, the output of my test was:
```
[
999,
2,
888
]
[
999,
2,
0
]
```
The second one was when `replacements_full = pa.array([999, 0, 888])`.
Wait, if `replacements_full` is `[999, 0, 888]`, the output is `[999, 2, 0]`.
Wait, what?
If `mask` is `[True, False, True]`, the elements at index 0 and 2 should be replaced.
Index 0: replaced by `replacements[0]` = 999.
Index 1: not replaced. Value is 2.
Index 2: replaced by `replacements[1]` = 0.
So the output `[999, 2, 0]` is correct.
And for the first case:
`replacements = pa.array([999, 888])`
Index 0: replaced by `replacements[0]` = 999.
Index 1: not replaced. Value is 2.
Index 2: replaced by `replacements[1]` = 888.
So the output `[999, 2, 888]` is correct.
So `replace_with_mask` takes the replacements sequentially for each `True` in the mask.
Now let's look back at the `narwhals` code:
```python
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
)
```
`values_native` has the same length as `indices_native`.
If `indices_native` are `[0, 2]`, then `values_native` is `[999, 888]`.
`values_native.take([0, 2])` tries to take elements at index 0 and 2 from `[999, 888]`.
This is where it fails because index 2 is out of bounds for an array of length 2.
The correct call should be:
```python
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native)
)
```
Because `values_native` is already sorted according to `indices_native` (due to the previous `.take(sorting_indices)` calls), it already contains the values in the order they will be used to fill the `True` positions in the mask.
Wait, let me double check the `sorting_indices` part:
```python
sorting_indices = pc.sort_indices(indices_native)
indices_native = indices_native.take(sorting_indices)
values_native = values_native.take(sorting_indices)
```
If `indices` were `[2, 0]` and `values` were `[888, 999]`:
1. `indices_native` = `[2, 0]`, `values_native` = `[888, 999]`
2. `sorting_indices` = `[1, 0]` (because `indices_native[1]=0` and `indices_native[0]=2`)
3. `indices_native` becomes `[0, 2]`
4. `values_native` becomes `[999, 888]`
Then `mask` is `[True, False, True]`.
`pc_replace_with_mask(self.native, mask, [999, 888])` will put 999 at index 0 and 888 at index 2.
This is exactly what we want!
So the fix is just to remove `.take(indices_native)` from the `pc_replace_with_mask` call.
Wait, I should also check if `scatter` is implemented in other backends to make sure it's consistent.
`narwhals` seems to have other backend implementations in `narwhals/_pandas_like`, `narwhals/_polars`, `narwhals/_duckdb`, `narwhals/_ibis`, `narwhals/_spark_like`.
Wait, the problem statement says `ArrowSeries.scatter` raises out of bound error. `ArrowSeries` is likely the implementation in `narwhals/_arrow/series.py`.
Let's see if other `Series` implementations also have `scatter`.
TOOL CALL · run_command
{
"command": "grep -rn \"def scatter\" narwhals/"
}Result of run_command 593 characters
{
"status": "ok",
"stdout": "narwhals/_compliant/series.py:251: def scatter(self, indices: int | Sequence[int], values: Any) -> Self: ...\nnarwhals/series.py:238: def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\nnarwhals/_pandas_like/series.py:273: def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\nnarwhals/_arrow/series.py:440: def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\nnarwhals/_polars/series.py:432: def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\n",
"stderr": "",
"exit_code": 0
}Generated tokens 1,183 tokens · stopped: STOP
Wait! My test showed:
```
[
999,
2,
888
]
```
When `replacements` was `[999, 888]` and `mask` was `[True, False, True]`.
That's 2 replacements and 2 True in mask.
So `replacements` does NOT have to be the same length as `mask`. It can be the same length as the number of True values in the mask.
Wait, the output of my test was:
```
[
999,
2,
888
]
[
999,
2,
0
]
```
The second one was when `replacements_full = pa.array([999, 0, 888])`.
Wait, if `replacements_full` is `[999, 0, 888]`, the output is `[999, 2, 0]`.
Wait, what?
If `mask` is `[True, False, True]`, the elements at index 0 and 2 should be replaced.
Index 0: replaced by `replacements[0]` = 999.
Index 1: not replaced. Value is 2.
Index 2: replaced by `replacements[1]` = 0.
So the output `[999, 2, 0]` is correct.
And for the first case:
`replacements = pa.array([999, 888])`
Index 0: replaced by `replacements[0]` = 999.
Index 1: not replaced. Value is 2.
Index 2: replaced by `replacements[1]` = 888.
So the output `[999, 2, 888]` is correct.
So `replace_with_mask` takes the replacements sequentially for each `True` in the mask.
Now let's look back at the `narwhals` code:
```python
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
)
```
`values_native` has the same length as `indices_native`.
If `indices_native` are `[0, 2]`, then `values_native` is `[999, 888]`.
`values_native.take([0, 2])` tries to take elements at index 0 and 2 from `[999, 888]`.
This is where it fails because index 2 is out of bounds for an array of length 2.
The correct call should be:
```python
return self._with_native(
pc_replace_with_mask(self.native, mask, values_native)
)
```
Because `values_native` is already sorted according to `indices_native` (due to the previous `.take(sorting_indices)` calls), it already contains the values in the order they will be used to fill the `True` positions in the mask.
Wait, let me double check the `sorting_indices` part:
```python
sorting_indices = pc.sort_indices(indices_native)
indices_native = indices_native.take(sorting_indices)
values_native = values_native.take(sorting_indices)
```
If `indices` were `[2, 0]` and `values` were `[888, 999]`:
1. `indices_native` = `[2, 0]`, `values_native` = `[888, 999]`
2. `sorting_indices` = `[1, 0]` (because `indices_native[1]=0` and `indices_native[0]=2`)
3. `indices_native` becomes `[0, 2]`
4. `values_native` becomes `[999, 888]`
Then `mask` is `[True, False, True]`.
`pc_replace_with_mask(self.native, mask, [999, 888])` will put 999 at index 0 and 888 at index 2.
This is exactly what we want!
So the fix is just to remove `.take(indices_native)` from the `pc_replace_with_mask` call.
Wait, I should also check if `scatter` is implemented in other backends to make sure it's consistent.
`narwhals` seems to have other backend implementations in `narwhals/_pandas_like`, `narwhals/_polars`, `narwhals/_duckdb`, `narwhals/_ibis`, `narwhals/_spark_like`.
Wait, the problem statement says `ArrowSeries.scatter` raises out of bound error. `ArrowSeries` is likely the implementation in `narwhals/_arrow/series.py`.
Let's see if other `Series` implementations also have `scatter`.
<channel|><|tool_call>call:run_command{command:<|"|>grep -rn "def scatter" narwhals/<|"|>}<tool_call|><|tool_response>
Turn 6at 214 s70 tokens out10,325 prompt tokens
It seems multiple backends have `scatter`. Let's check `narwhals/series.py` to see what it does. It's probably the base class or the dispatcher.
TOOL CALL · read_file
{
"filepath": "narwhals/series.py",
"start_line": 238
}Result of read_file 4,746 characters
{
"status": "ok",
"filepath": "narwhals/series.py",
"content": " def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\n \"\"\"Set value(s) at given position(s).\n\n Arguments:\n indices: Position(s) to set items at.\n values: Values to set.\n\n Returns:\n A new Series with values set at given positions.\n\n Note:\n This method always returns a new Series, without modifying the original one.\n Using this function in a for-loop is an anti-pattern, we recommend building\n up your positions and values beforehand and doing an update in one go.\n\n For example, instead of\n\n ```python\n for i in [1, 3, 2]:\n value = some_function(i)\n s = s.scatter(i, value)\n ```\n\n prefer\n\n ```python\n positions = [1, 3, 2]\n values = [some_function(x) for x in positions]\n s = s.scatter(positions, values)\n ```\n\n Examples:\n >>> import pyarrow as pa\n >>> import narwhals as nw\n >>>\n >>> df_native = pa.table({\"a\": [1, 2, 3], \"b\": [4, 5, 6]})\n >>> df_nw = nw.from_native(df_native)\n >>> df_nw.with_columns(df_nw[\"a\"].scatter([0, 1], [999, 888])).to_native()\n pyarrow.Table\n a: int64\n b: int64\n ----\n a: [[999,888,3]]\n b: [[4,5,6]]\n \"\"\"\n return self._with_compliant(\n self._compliant_series.scatter(indices, self._extract_native(values))\n )\n\n @property\n def shape(self) -> tuple[int]:\n \"\"\"Get the shape of the Series.\n\n Returns:\n A tuple containing the length of the Series.\n\n Examples:\n >>> import pandas as pd\n >>> import narwhals as nw\n >>>\n >>> s_native = pd.Series([1, 2, 3])\n >>> nw.from_native(s_native, series_only=True).shape\n (3,)\n \"\"\"\n return (self._compliant_series.len(),)\n\n def _extract_native(self, arg: Any) -> Any:\n from narwhals.series import Series\n\n if isinstance(arg, Series):\n return arg._compliant_series\n return arg\n\n def _with_compliant(self, series: Any) -> Self:\n return self.__class__(series, level=self._level)\n\n def pipe(self, function: Callable[[Any], Self], *args: Any, **kwargs: Any) -> Self:\n \"\"\"Pipe function call.\n\n Returns:\n A new Series with the results of the piped function applied.\n\n Examples:\n >>> import polars as pl\n >>> import narwhals as nw\n >>> s_native = pl.Series([1, 2, 3])\n >>> s = nw.from_native(s_native, series_only=True)\n >>> s.pipe(lambda x: x + 2).to_native() # doctest: +NORMALIZE_WHITESPACE\n shape: (3,)\n Series: '' [i64]\n [\n 3\n 4\n 5\n ]\n \"\"\"\n return function(self, *args, **kwargs)\n\n def __repr__(self) -> str: # pragma: no cover\n return generate_repr(\"Narwhals Series\", self.to_native().__repr__())\n\n def __len__(self) -> int:\n return len(self._compliant_series)\n\n def len(self) -> int:\n r\"\"\"Return the number of elements in the Series.\n\n Null values count towards the total.\n\n Returns:\n The number of elements in the Series.\n\n Examples:\n >>> import pyarrow as pa\n >>> import narwhals as nw\n >>>\n >>> s_native = pa.chunked_array([[1, 2, None]])\n >>> nw.from_native(s_native, series_only=True).len()\n 3\n \"\"\"\n return len(self._compliant_series)\n\n @property\n def dtype(self) -> DType:\n \"\"\"Get the data type of the Series.\n\n Returns:\n The data type of the Series.\n\n Examples:\n >>> import pandas as pd\n >>> import narwhals as nw\n >>>\n >>> s_native = pd.Series([1, 2, 3])\n >>> nw.from_native(s_native, series_only=True).dtype\n Int64\n \"\"\"\n return self._compliant_series.dtype\n\n @property\n def name(self) -> str:\n \"\"\"Get the name of the Series.\n\n Returns:\n The name of the Series.\n\n Examples:\n >>> import polars as pl\n >>> import narwhals as nw\n >>>",
"start_line": 238,
"end_line": 387,
"total_lines": 2699,
"is_truncated": true
}Generated tokens 70 tokens · stopped: STOP
It seems multiple backends have `scatter`. Let's check `narwhals/series.py` to see what it does. It's probably the base class or the dispatcher.
<channel|><|tool_call>call:read_file{filepath:<|"|>narwhals/series.py<|"|>,start_line:238}<tool_call|><|tool_response>
Turn 7at 227 s200 tokens out11,804 prompt tokens
In `narwhals/series.py`, `scatter` calls `self._compliant_series.scatter`. Let's check `narwhals/_arrow/series.py` again. Wait, I already saw `narwhals/_arrow/series.py` has `scatter`. The `ArrowSeries` in `narwhals/_arrow/series.py` is likely the one used when the backend is pyarrow. Wait, I see `narwhals/_compliant/series.py` also has `scatter`. Let's check `narwhals/_arrow/series.py` again. I'll modify it and test. But before that, I should check if `narwhals/_polars/series.py` has the same bug.
TOOL CALL · read_file
{
"filepath": "narwhals/_polars/series.py",
"start_line": 432
}Result of read_file 6,218 characters
{
"status": "ok",
"filepath": "narwhals/_polars/series.py",
"content": " def scatter(self, indices: int | Sequence[int], values: Any) -> Self:\n s = self.native.clone().scatter(indices, extract_native(values))\n return self._with_native(s)\n\n def value_counts(\n self, *, sort: bool, parallel: bool, name: str | None, normalize: bool\n ) -> PolarsDataFrame:\n from narwhals._polars.dataframe import PolarsDataFrame\n\n if self._backend_version < (1, 0, 0):\n value_name_ = name or (\"proportion\" if normalize else \"count\")\n\n result = self.native.value_counts(sort=sort, parallel=parallel).select(\n **{\n (self.native.name): pl.col(self.native.name),\n value_name_: pl.col(\"count\") / pl.sum(\"count\")\n if normalize\n else pl.col(\"count\"),\n }\n )\n else:\n result = self.native.value_counts(\n sort=sort, parallel=parallel, name=name, normalize=normalize\n )\n return PolarsDataFrame.from_native(result, context=self)\n\n def cum_count(self, *, reverse: bool) -> Self:\n return self._with_native(self.native.cum_count(reverse=reverse))\n\n def __contains__(self, other: Any) -> bool:\n try:\n return self.native.__contains__(other)\n except Exception as e: # noqa: BLE001\n raise catch_polars_exception(e) from None\n\n def hist( # noqa: C901, PLR0912\n self,\n bins: list[float | int] | None,\n *,\n bin_count: int | None,\n include_breakpoint: bool,\n ) -> PolarsDataFrame:\n from narwhals._polars.dataframe import PolarsDataFrame\n\n if (bins is not None and len(bins) <= 1) or (bin_count == 0): # pragma: no cover\n data: list[pl.Series] = []\n if include_breakpoint:\n data.append(pl.Series(\"breakpoint\", [], dtype=pl.Float64))\n data.append(pl.Series(\"count\", [], dtype=pl.UInt32))\n return PolarsDataFrame.from_native(pl.DataFrame(data), context=self)\n\n if self.native.count() < 1:\n data_dict: dict[str, Sequence[Any] | pl.Series]\n if bins is not None:\n data_dict = {\n \"breakpoint\": bins[1:],\n \"count\": pl.zeros(n=len(bins) - 1, dtype=pl.Int64, eager=True),\n }\n elif (bin_count is not None) and bin_count == 1:\n data_dict = {\"breakpoint\": [1.0], \"count\": [0]}\n elif (bin_count is not None) and bin_count > 1:\n data_dict = {\n \"breakpoint\": pl.int_range(1, bin_count + 1, eager=True) / bin_count,\n \"count\": pl.zeros(n=bin_count, dtype=pl.Int64, eager=True),\n }\n else: # pragma: no cover\n msg = (\n \"congratulations, you entered unreachable code - please report a bug\"\n )\n raise AssertionError(msg)\n if not include_breakpoint:\n del data_dict[\"breakpoint\"]\n return PolarsDataFrame.from_native(pl.DataFrame(data_dict), context=self)\n\n # polars <1.15 does not adjust the bins when they have equivalent min/max\n # polars <1.5 with bin_count=...\n # returns bins that range from -inf to +inf and has bin_count + 1 bins.\n # for compat: convert `bin_count=` call to `bins=`\n if (self._backend_version < (1, 15)) and (\n bin_count is not None\n ): # pragma: no cover\n lower = cast(\"float\", self.native.min())\n upper = cast(\"float\", self.native.max())\n if lower == upper:\n width = 1 / bin_count\n lower -= 0.5\n upper += 0.5\n else:\n width = (upper - lower) / bin_count\n\n bins = (pl.int_range(0, bin_count + 1, eager=True) * width + lower).to_list()\n bin_count = None\n\n # Polars inconsistently handles NaN values when computing histograms\n # against predefined bins: https://github.com/pola-rs/polars/issues/21082\n series = self.native\n if self._backend_version < (1, 15) or bins is not None:\n series = series.set(series.is_nan(), None)\n\n df = series.hist(\n bins,\n bin_count=bin_count,\n include_category=False,\n include_breakpoint=include_breakpoint,\n )\n\n if not include_breakpoint:\n df.columns = [\"count\"]\n\n if self._backend_version < (1, 0) and include_breakpoint:\n df = df.rename({\"break_point\": \"breakpoint\"})\n\n # polars<1.15 implicitly adds -inf and inf to either end of bins\n if self._backend_version < (1, 15) and bins is not None: # pragma: no cover\n r = pl.int_range(0, len(df))\n df = df.filter((r > 0) & (r < len(df) - 1))\n\n # polars<1.27 makes the lowest bin a left/right closed interval.\n if self._backend_version < (1, 27) and bins is not None:\n df[0, \"count\"] += (series == bins[0]).sum()\n\n return PolarsDataFrame.from_native(df, context=self)\n\n def to_polars(self) -> pl.Series:\n return self.native\n\n @property\n def dt(self) -> PolarsSeriesDateTimeNamespace:\n return PolarsSeriesDateTimeNamespace(self)\n\n @property\n def str(self) -> PolarsSeriesStringNamespace:\n return PolarsSeriesStringNamespace(self)\n\n @property\n def cat(self) -> PolarsSeriesCatNamespace:\n return PolarsSeriesCatNamespace(self)\n\n @property\n def struct(self) -> PolarsSeriesStructNamespace:\n return PolarsSeriesStructNamespace(self)\n\n __add__: Method[Self]\n __and__: Method[Self]\n __floordiv__: Method[Self]\n __invert__: Method[Self]\n __iter__: Method[Iterator[Any]]\n __mod__: Method[Self]\n __mul__: Method[Self]\n __or__: Method[Self]",
"start_line": 432,
"end_line": 581,
"total_lines": 741,
"is_truncated": true
}Generated tokens 200 tokens · stopped: STOP
In `narwhals/series.py`, `scatter` calls `self._compliant_series.scatter`.
Let's check `narwhals/_arrow/series.py` again.
Wait, I already saw `narwhals/_arrow/series.py` has `scatter`.
The `ArrowSeries` in `narwhals/_arrow/series.py` is likely the one used when the backend is pyarrow.
Wait, I see `narwhals/_compliant/series.py` also has `scatter`.
Let's check `narwhals/_arrow/series.py` again.
I'll modify it and test.
But before that, I should check if `narwhals/_polars/series.py` has the same bug.
<channel|><|tool_call>call:read_file{filepath:<|"|>narwhals/_polars/series.py<|"|>,start_line:432}<tool_call|><|tool_response>
Turn 8at 239 s159 tokens out13,843 prompt tokens
Polars' `scatter` just calls `self.native.scatter`, so it's handled by Polars itself. The bug is definitely in `narwhals/_arrow/series.py`. Let's apply the fix.
TOOL CALL · edit_file
{
"filepath": "narwhals/_arrow/series.py",
"new_string": " return self._with_native(\n pc_replace_with_mask(self.native, mask, values_native)\n )\n",
"old_string": " return self._with_native(\n pc_replace_with_mask(self.native, mask, values_native.take(indices_native))\n )\n"
}Result of edit_file 566 characters
{
"status": "ok",
"filepath": "narwhals/_arrow/series.py",
"occurrences": 1,
"strategy": "exact",
"diff": "--- a/narwhals/_arrow/series.py\n+++ b/narwhals/_arrow/series.py\n@@ -468,7 +468,7 @@\n # - Missing return type\n pc_replace_with_mask: Incomplete = pc.replace_with_mask\n return self._with_native(\n- pc_replace_with_mask(self.native, mask, values_native.take(indices_native))\n+ pc_replace_with_mask(self.native, mask, values_native)\n )\n \n def to_list(self) -> list[Any]:\n",
"is_truncated": false
}Generated tokens 159 tokens · stopped: STOP
Polars' `scatter` just calls `self.native.scatter`, so it's handled by Polars itself.
The bug is definitely in `narwhals/_arrow/series.py`.
Let's apply the fix.
<channel|><|tool_call>call:edit_file{filepath:<|"|>narwhals/_arrow/series.py<|"|>,new_string:<|"|> return self._with_native(
pc_replace_with_mask(self.native, mask, values_native)
)
<|"|>,old_string:<|"|> return self._with_native(
pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
)
<|"|>}<tool_call|><|tool_response>
Turn 9at 275 s622 tokens out14,212 prompt tokens
Now let's verify the fix with the reproduction script and other edge cases. I'll use a few more cases: 1. Single index (the one that failed). 2. Multiple indices (the one that failed). 3. Empty indices/values. 4. Indices that are 0. 5. Indices that are full length. 6. Unsorted indices. 7. Indices that repeat (if pyarrow supports that). Wait, if indices repeat, `mask[indices_native] = True` will only mark that position once. But `values_native` will have as many elements as `indices_native`. Pyarrow's `replace_with_mask` takes values sequentially for each `True` in the mask. If `indices = [0, 0]`, `mask` has only one `True` (at index 0). Then `replace_with_mask` will only use the first value from `values_native`. This might be a bug or intended behavior. Let's see what pandas/polars do. Actually, let's just test the reported bug first and then see about repeats.
TOOL CALL · run_command
{
"command": "python3 - <<'PY'\nimport narwhals as nw\nimport pyarrow as pa\nimport numpy as np\n\ndef test_scatter(indices, values, expected):\n tbl = pa.table({\"a\": [1, 2, 3]})\n frame = nw.from_native(tbl, eager_only=True)\n ser = frame[\"a\"]\n result = ser.scatter(indices, values).to_numpy()\n actual = list(result)\n print(f\"indices={indices}, values={values}, expected={expected}, actual={actual}\")\n assert actual == expected\n\n# Case 1: Single index (reported bug)\ntest_scatter(1, 999, [1, 999, 3])\n\n# Case 2: Multiple indices (reported bug)\ntest_scatter([0, 2], [999, 888], [999, 2, 888])\n\n# Case 3: Index 0\ntest_scatter(0, 999, [999, 2, 3])\n\n# Case 4: Full length\ntest_scatter([0, 1, 2], [9, 8, 7], [9, 8, 7])\n\n# Case 5: Unsorted indices\ntest_scatter([2, 0], [888, 999], [999, 2, 888])\n\n# Case 6: Empty\ntest_scatter([], [], [1, 2, 3])\n\nprint(\"All tests passed!\")\nPY\n"
}Result of run_command 2,420 characters
{
"status": "error",
"error_type": "CommandError",
"error_message": "Traceback (most recent call last):\n File \"<stdin>\", line 30, in <module>\n File \"<stdin>\", line 9, in test_scatter\n File \"/workspace/narwhals/series.py\", line 284, in scatter\n self._compliant_series.scatter(indices, self._extract_native(values))\n File \"/workspace/narwhals/_arrow/series.py\", line 471, in scatter\n pc_replace_with_mask(self.native, mask, values_native)\n File \"/usr/local/lib/python3.10/site-packages/pyarrow/compute.py\", line 254, in wrapper\n return func.call(args, None, memory_pool)\n File \"pyarrow/_compute.pyx\", line 405, in pyarrow._compute.Function.call\n File \"pyarrow/error.pxi\", line 155, in pyarrow.lib.pyarrow_internal_check_status\n File \"pyarrow/error.pxi\", line 92, in pyarrow.lib.check_status\npyarrow.lib.ArrowNotImplementedError: Function 'replace_with_mask' has no kernel matching input types (int64, bool, null)\n",
"details": {
"stdout": "indices=1, values=999, expected=[1, 999, 3], actual=[np.int64(1), np.int64(999), np.int64(3)]\nindices=[0, 2], values=[999, 888], expected=[999, 2, 888], actual=[np.int64(999), np.int64(2), np.int64(888)]\nindices=0, values=999, expected=[999, 2, 3], actual=[np.int64(999), np.int64(2), np.int64(3)]\nindices=[0, 1, 2], values=[9, 8, 7], expected=[9, 8, 7], actual=[np.int64(9), np.int64(8), np.int64(7)]\nindices=[2, 0], values=[888, 999], expected=[999, 2, 888], actual=[np.int64(999), np.int64(2), np.int64(888)]\n",
"stderr": "Traceback (most recent call last):\n File \"<stdin>\", line 30, in <module>\n File \"<stdin>\", line 9, in test_scatter\n File \"/workspace/narwhals/series.py\", line 284, in scatter\n self._compliant_series.scatter(indices, self._extract_native(values))\n File \"/workspace/narwhals/_arrow/series.py\", line 471, in scatter\n pc_replace_with_mask(self.native, mask, values_native)\n File \"/usr/local/lib/python3.10/site-packages/pyarrow/compute.py\", line 254, in wrapper\n return func.call(args, None, memory_pool)\n File \"pyarrow/_compute.pyx\", line 405, in pyarrow._compute.Function.call\n File \"pyarrow/error.pxi\", line 155, in pyarrow.lib.pyarrow_internal_check_status\n File \"pyarrow/error.pxi\", line 92, in pyarrow.lib.check_status\npyarrow.lib.ArrowNotImplementedError: Function 'replace_with_mask' has no kernel matching input types (int64, bool, null)\n",
"exit_code": 1
}
}Generated tokens 622 tokens · stopped: STOP
Now let's verify the fix with the reproduction script and other edge cases.
I'll use a few more cases:
1. Single index (the one that failed).
2. Multiple indices (the one that failed).
3. Empty indices/values.
4. Indices that are 0.
5. Indices that are full length.
6. Unsorted indices.
7. Indices that repeat (if pyarrow supports that).
Wait, if indices repeat, `mask[indices_native] = True` will only mark that position once.
But `values_native` will have as many elements as `indices_native`.
Pyarrow's `replace_with_mask` takes values sequentially for each `True` in the mask.
If `indices = [0, 0]`, `mask` has only one `True` (at index 0).
Then `replace_with_mask` will only use the first value from `values_native`.
This might be a bug or intended behavior. Let's see what pandas/polars do.
Actually, let's just test the reported bug first and then see about repeats.
<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY'
import narwhals as nw
import pyarrow as pa
import numpy as np
def test_scatter(indices, values, expected):
tbl = pa.table({"a": [1, 2, 3]})
frame = nw.from_native(tbl, eager_only=True)
ser = frame["a"]
result = ser.scatter(indices, values).to_numpy()
actual = list(result)
print(f"indices={indices}, values={values}, expected={expected}, actual={actual}")
assert actual == expected
# Case 1: Single index (reported bug)
test_scatter(1, 999, [1, 999, 3])
# Case 2: Multiple indices (reported bug)
test_scatter([0, 2], [999, 888], [999, 2, 888])
# Case 3: Index 0
test_scatter(0, 999, [999, 2, 3])
# Case 4: Full length
test_scatter([0, 1, 2], [9, 8, 7], [9, 8, 7])
# Case 5: Unsorted indices
test_scatter([2, 0], [888, 999], [999, 2, 888])
# Case 6: Empty
test_scatter([], [], [1, 2, 3])
print("All tests passed!")
PY
<|"|>}<tool_call|><|tool_response>
Turn 10at 316 s879 tokens out15,792 prompt tokens
The tests passed until the empty case:
```
indices=[], values=[], expected=[1, 2, 3], actual=[np.int64(1), np.int64(2), np.int64(3)]
```
Wait, it looks like it passed the empty case too? Let's look at the output.
Wait, the error is:
```
pyarrow.lib.ArrowNotImplementedError: Function 'replace_with_mask' has no kernel matching input types (int64, bool, null)
```
This happened at the end. Let's see the stdout again.
```
indices=1, values=999, expected=[1, 999, 3], actual=[np.int64(1), np.int64(999), np.int64(3)]
indices=[0, 2], values=[999, 888], expected=[999, 2, 888], actual=[np.int64(999), np.int64(2), np.int64(888)]
indices=0, values=999, expected=[999, 2, 3], actual=[np.int64(999), np.int64(2), np.int64(3)]
indices=[0, 1, 2], values=[9, 8, 7], expected=[9, 8, 7], actual=[np.int64(9), np.int64(8), np.int64(7)]
indices=[2, 0], values=[888, 999], expected=[999, 2, 888], actual=[np.int64(999), np.int64(2), np.int64(888)]
```
Wait, Case 6 (empty) is missing from the stdout!
Let's see:
Case 1: indices=1, values=999 -> printed.
Case 2: indices=[0, 2], values=[999, 888] -> printed.
Case 3: indices=0, values=999 -> printed.
Case 4: indices=[0, 1, 2], values=[9, 8, 7] -> printed.
Case 5: indices=[2, 0], values=[888, 999] -> printed.
Total 5 printed cases. Case 6 was the 6th. It failed.
The error `Function 'replace_with_mask' has no kernel matching input types (int64, bool, null)` means that when `values` is `[]`, `values_native` becomes a `null` array (or an empty array with `null` type), and `replace_with_mask` doesn't know how to handle it.
Let's check how `values_native` is created when `indices` is `[]`.
```python
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
indices_native = pa.array(indices)
if isinstance(values, self.__class__):
values_native = values.native.combine_chunks()
else:
pa_array: Incomplete = pa.array
values_native = pa_array(values)
```
If `indices = []` and `values = []`, `indices_native = pa.array([])` and `values_native = pa.array([])`.
Pyarrow's `pa.array([])` might be creating a `null` type array.
Let's check:
TOOL CALL · run_command
{
"command": "python3 -c \"import pyarrow as pa; print(pa.array([]).type)\""
}Result of run_command 66 characters
{
"status": "ok",
"stdout": "null\n",
"stderr": "",
"exit_code": 0
}Generated tokens 879 tokens · stopped: STOP
The tests passed until the empty case:
```
indices=[], values=[], expected=[1, 2, 3], actual=[np.int64(1), np.int64(2), np.int64(3)]
```
Wait, it looks like it passed the empty case too? Let's look at the output.
Wait, the error is:
```
pyarrow.lib.ArrowNotImplementedError: Function 'replace_with_mask' has no kernel matching input types (int64, bool, null)
```
This happened at the end. Let's see the stdout again.
```
indices=1, values=999, expected=[1, 999, 3], actual=[np.int64(1), np.int64(999), np.int64(3)]
indices=[0, 2], values=[999, 888], expected=[999, 2, 888], actual=[np.int64(999), np.int64(2), np.int64(888)]
indices=0, values=999, expected=[999, 2, 3], actual=[np.int64(999), np.int64(2), np.int64(3)]
indices=[0, 1, 2], values=[9, 8, 7], expected=[9, 8, 7], actual=[np.int64(9), np.int64(8), np.int64(7)]
indices=[2, 0], values=[888, 999], expected=[999, 2, 888], actual=[np.int64(999), np.int64(2), np.int64(888)]
```
Wait, Case 6 (empty) is missing from the stdout!
Let's see:
Case 1: indices=1, values=999 -> printed.
Case 2: indices=[0, 2], values=[999, 888] -> printed.
Case 3: indices=0, values=999 -> printed.
Case 4: indices=[0, 1, 2], values=[9, 8, 7] -> printed.
Case 5: indices=[2, 0], values=[888, 999] -> printed.
Total 5 printed cases. Case 6 was the 6th. It failed.
The error `Function 'replace_with_mask' has no kernel matching input types (int64, bool, null)` means that when `values` is `[]`, `values_native` becomes a `null` array (or an empty array with `null` type), and `replace_with_mask` doesn't know how to handle it.
Let's check how `values_native` is created when `indices` is `[]`.
```python
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
indices_native = pa.array(indices)
if isinstance(values, self.__class__):
values_native = values.native.combine_chunks()
else:
pa_array: Incomplete = pa.array
values_native = pa_array(values)
```
If `indices = []` and `values = []`, `indices_native = pa.array([])` and `values_native = pa.array([])`.
Pyarrow's `pa.array([])` might be creating a `null` type array.
Let's check:
<channel|><|tool_call>call:run_command{command:<|"|>python3 -c "import pyarrow as pa; print(pa.array([]).type)"<|"|>}<tool_call|><|tool_response>
Turn 11at 418 s490 tokens out5,322 prompt tokens
Yes, it's `null` type.
If the original series is `int64`, then `replace_with_mask(int64_series, mask, null_array)` fails because the replacement array must have the same type as the original series.
So we need to handle the case where `values_native` is null/empty.
Actually, if `indices` is empty, the mask is all `False`, so we don't even need to call `replace_with_mask`, we can just return `self`.
Let's see if pandas/polars handles this.
In pandas: `s.scatter([], [])` should return `s`.
Let's look at `ArrowSeries.scatter` again.
```python
def scatter(self, indices: int | Sequence[int], values: Any) -> Self:
# ...
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
indices_native = pa.array(indices)
# ...
values_native = pa_array(values)
mask = pa.compute.equal(pa.array(range(len(self.native))), indices_native) # WRONG
```
Wait, I misread the `mask` creation in my previous thought. Let's check the code again.
```python
mask = pa.compute.equal(
pa.array(range(len(self.native))), indices_native
) # This is wrong if indices is not a scale
```
Wait, the code is:
```python
mask = pa.compute.equal(
pa.array(range(len(self.native))), indices_native
)
```
This only works if `indices_native` is a single value (scalar). If it's an array, `pa.compute.equal` will try to do element-wise comparison.
Let's check `_arrow/series.py` again.
TOOL CALL · read_file
{
"end_line": 480,
"filepath": "narwhals/_arrow/series.py",
"start_line": 450
}Result of read_file 1,515 characters
{
"status": "ok",
"filepath": "narwhals/_arrow/series.py",
"content": " indices_native = pa.array(indices)\n if isinstance(values, self.__class__):\n values_native = values.native.combine_chunks()\n else:\n # NOTE: Requires fixes in https://github.com/zen-xu/pyarrow-stubs/pull/209\n pa_array: Incomplete = pa.array\n values_native = pa_array(values)\n\n sorting_indices = pc.sort_indices(indices_native)\n indices_native = indices_native.take(sorting_indices)\n values_native = values_native.take(sorting_indices)\n\n mask: _1DArray = np.zeros(self.len(), dtype=bool)\n mask[indices_native] = True\n # NOTE: Multiple issues\n # - Missing `values` type\n # - `mask` accepts a `np.ndarray`, but not mentioned in stubs\n # - Missing `replacements` type\n # - Missing return type\n pc_replace_with_mask: Incomplete = pc.replace_with_mask\n return self._with_native(\n pc_replace_with_mask(self.native, mask, values_native)\n )\n\n def to_list(self) -> list[Any]:\n return self.native.to_pylist()\n\n def __array__(self, dtype: Any = None, *, copy: bool | None = None) -> _1DArray:\n return self.native.__array__(dtype=dtype, copy=copy)\n\n def to_numpy(self, dtype: Any = None, *, copy: bool | None = None) -> _1DArray:",
"start_line": 450,
"end_line": 480,
"total_lines": 1170,
"is_truncated": false
}Generated tokens 490 tokens · stopped: STOP
Yes, it's `null` type.
If the original series is `int64`, then `replace_with_mask(int64_series, mask, null_array)` fails because the replacement array must have the same type as the original series.
So we need to handle the case where `values_native` is null/empty.
Actually, if `indices` is empty, the mask is all `False`, so we don't even need to call `replace_with_mask`, we can just return `self`.
Let's see if pandas/polars handles this.
In pandas: `s.scatter([], [])` should return `s`.
Let's look at `ArrowSeries.scatter` again.
```python
def scatter(self, indices: int | Sequence[int], values: Any) -> Self:
# ...
if isinstance(indices, int):
indices_native = pa.array([indices])
values_native = pa.array([values])
else:
indices_native = pa.array(indices)
# ...
values_native = pa_array(values)
mask = pa.compute.equal(pa.array(range(len(self.native))), indices_native) # WRONG
```
Wait, I misread the `mask` creation in my previous thought. Let's check the code again.
```python
mask = pa.compute.equal(
pa.array(range(len(self.native))), indices_native
) # This is wrong if indices is not a scale
```
Wait, the code is:
```python
mask = pa.compute.equal(
pa.array(range(len(self.native))), indices_native
)
```
This only works if `indices_native` is a single value (scalar). If it's an array, `pa.compute.equal` will try to do element-wise comparison.
Let's check `_arrow/series.py` again.
<channel|><|tool_call>call:read_file{filepath:<|"|>narwhals/_arrow/series.py<|"|>,start_line:450,end_line:480}<tool_call|><|tool_response>
Patch, tests and logs
Final code change Included
diff --git a/narwhals/_arrow/series.py b/narwhals/_arrow/series.py
index e22d20f..a846e50 100644
--- a/narwhals/_arrow/series.py
+++ b/narwhals/_arrow/series.py
@@ -468,7 +468,7 @@ class ArrowSeries(EagerSeries["ChunkedArrayAny"]):
# - Missing return type
pc_replace_with_mask: Incomplete = pc.replace_with_mask
return self._with_native(
- pc_replace_with_mask(self.native, mask, values_native.take(indices_native))
+ pc_replace_with_mask(self.native, mask, values_native)
)
def to_list(self) -> list[Any]:
Test output Included
============================= test session starts ============================== collected 25 items tests/series_only/scatter_test.py ......................... [100%] ==================================== PASSES ==================================== - generated xml file: /tmp/rebench-grade-e4b415ad6343480cba87d259f711ebde.xml -- =========================== short test summary info ============================ PASSED tests/series_only/scatter_test.py::test_scatter_unchanged[pyarrow] PASSED tests/series_only/scatter_test.py::test_scatter[pandas] PASSED tests/series_only/scatter_test.py::test_single_series[pandas[pyarrow]] PASSED tests/series_only/scatter_test.py::test_scatter[pandas[pyarrow]] PASSED tests/series_only/scatter_test.py::test_scatter_2862[pyarrow] PASSED tests/series_only/scatter_test.py::test_single_series[pyarrow] PASSED tests/series_only/scatter_test.py::test_scatter[pyarrow] PASSED tests/series_only/scatter_test.py::test_scatter_integer[pandas] PASSED tests/series_only/scatter_test.py::test_scatter_2862[pandas[pyarrow]] PASSED tests/series_only/scatter_test.py::test_scatter_integer[pyarrow] PASSED tests/series_only/scatter_test.py::test_single_series[pandas] PASSED tests/series_only/scatter_test.py::test_scatter_unchanged[polars[eager]] PASSED tests/series_only/scatter_test.py::test_scatter_unordered_indices[pyarrow] PASSED tests/series_only/scatter_test.py::test_scatter_integer[pandas[pyarrow]] PASSED tests/series_only/scatter_test.py::test_scatter_unchanged[pandas[pyarrow]] PASSED tests/series_only/scatter_test.py::test_single_series[polars[eager]] PASSED tests/series_only/scatter_test.py::test_scatter_2862[polars[eager]] PASSED tests/series_only/scatter_test.py::test_scatter_integer[polars[eager]] PASSED tests/series_only/scatter_test.py::test_scatter_unordered_indices[pandas[pyarrow]] PASSED tests/series_only/scatter_test.py::test_scatter_unordered_indices[polars[eager]] PASSED tests/series_only/scatter_test.py::test_scatter_2862[pandas] PASSED tests/series_only/scatter_test.py::test_scatter_unordered_indices[pandas] PASSED tests/series_only/scatter_test.py::test_scatter[polars[eager]] PASSED tests/series_only/scatter_test.py::test_scatter_unchanged[pandas] PASSED tests/series_only/scatter_test.py::test_scatter_indices ============================== 25 passed in 0.54s ==============================
Test errors Included
Test report (JUnit) Included
<?xml version="1.0" encoding="utf-8"?><testsuites name="pytest tests"><testsuite name="pytest" errors="0" failures="0" skipped="0" tests="25" time="0.096" timestamp="2026-11-14T04:07:51.258666+00:00" hostname="80df487c28d6"><testcase classname="tests.series_only.scatter_test" name="test_scatter_unchanged[pyarrow]" time="0.022" /><testcase classname="tests.series_only.scatter_test" name="test_scatter[pandas]" time="0.021" /><testcase classname="tests.series_only.scatter_test" name="test_single_series[pandas[pyarrow]]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter[pandas[pyarrow]]" time="0.002" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_2862[pyarrow]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_single_series[pyarrow]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter[pyarrow]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_integer[pandas]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_2862[pandas[pyarrow]]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_integer[pyarrow]" time="0.000" /><testcase classname="tests.series_only.scatter_test" name="test_single_series[pandas]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_unchanged[polars[eager]]" time="0.012" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_unordered_indices[pyarrow]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_integer[pandas[pyarrow]]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_unchanged[pandas[pyarrow]]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_single_series[polars[eager]]" time="0.000" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_2862[polars[eager]]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_integer[polars[eager]]" time="0.000" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_unordered_indices[pandas[pyarrow]]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_unordered_indices[polars[eager]]" time="0.000" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_2862[pandas]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_unordered_indices[pandas]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter[polars[eager]]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_unchanged[pandas]" time="0.001" /><testcase classname="tests.series_only.scatter_test" name="test_scatter_indices" time="0.001" /></testsuite></testsuites>
Agent log Included
[ 0.0s] 📋 System Prompt: You are a principal Python software engineer resolving a repository issue in `/workspace`.
[ 0.0s] 🎯 Task Prompt: You are evaluating a software engineering task for repository narwhals-dev/narwhals.
[ 18.1s] 💭 (195 chars) "The user is reporting a bug in `ArrowSeries.scatter` where it raises an "out of bound" error
when `indices` is not 0 and..."
[ 18.1s] 🔧 run_command (22 lines) python3 - <<'PY'
[ 19.2s] → Testing single index scatter...
[ 28.3s] 💭 (186 chars) "The bug is reproduced. Now I need to find where `scatter` is implemented for Arrow-backed
series.
I'll search for `scat..."
[ 28.3s] 🔧 run_command grep -rn "scatter" narwhals/_arrow/series.py
[ 28.3s] → 440: def scatter(self, indices: int | Sequence[int], values: Any) -> Self:
[ 35.6s] 💭 (149 chars) "Okay, `scatter` is defined in `narwhals/_arrow/series.py` at line 440.
Let's examine the implementation of `scatter` in..."
[ 35.6s] 📖 read_file (narwhals/_arrow/series.py)
[ 35.6s] ✓ {'status': 'ok', 'filepath': 'narwhals/_arrow/series.py', 'content': ' def scatter(self, indices: int
| Sequence[int]…
[ 126.9s] 💭 (4670 chars) "Here is the code for `scatter`:
```python
def scatter(self, indices: int | Sequence[int], values: Any) -> Self:
..."
[ 126.9s] 🔧 run_command (16 lines) python3 - <<'PY'
[ 127.3s] → [
[ 207.3s] 💭 (3281 chars) "Wait! My test showed:
```
[
999,
2,
888
]
```
When `replacements` was `[999, 888]` and `mask` was `[True, False, T..."
[ 207.3s] 🔧 run_command grep -rn "def scatter" narwhals/
[ 207.3s] → narwhals/_compliant/series.py:251: def scatter(self, indices: int | Sequence[int], values: Any) ->
Self: ...
[ 211.5s] 💭 (144 chars) "It seems multiple backends have `scatter`. Let's check `narwhals/series.py` to see what it
does. It's probably the base ..."
[ 211.5s] 📖 read_file (narwhals/series.py)
[ 211.5s] ✓ {'status': 'ok', 'filepath': 'narwhals/series.py', 'content': ' def scatter(self, indices: int |
Sequence[int], value…
[ 224.5s] 💭 (507 chars) "In `narwhals/series.py`, `scatter` calls `self._compliant_series.scatter`.
Let's check `narwhals/_arrow/series.py` agai..."
[ 224.5s] 📖 read_file (narwhals/_polars/series.py)
[ 224.5s] ✓ {'status': 'ok', 'filepath': 'narwhals/_polars/series.py', 'content': ' def scatter(self, indices:
int | Sequence[int…
[ 236.8s] 💭 (162 chars) "Polars' `scatter` just calls `self.native.scatter`, so it's handled by Polars itself.
The bug is definitely in `narwhal..."
[ 236.8s] ✏️ edit_file (narwhals/_arrow/series.py)
[ 237.0s] ✓ {'status': 'ok', 'filepath': 'narwhals/_arrow/series.py', 'occurrences': 1, 'strategy': 'exact', 'diff':
'--- a/narwhals…
[ 272.3s] 💭 (875 chars) "Now let's verify the fix with the reproduction script and other edge cases.
I'll use a few more cases:
1. Single index (..."
[ 272.3s] 🔧 run_command (34 lines) python3 - <<'PY'
[ 272.7s] → error (exit 0):
[ 313.5s] 💭 (2251 chars) "The tests passed until the empty case:
```
indices=[], values=[], expected=[1, 2, 3], actual=[np.int64(1), np.int64(2), ..."
[ 313.5s] 🔧 run_command python3 -c "import pyarrow as pa; print(pa.array([]).type)"
[ 313.9s] → null
[ 415.2s] 💭 (1558 chars) "Yes, it's `null` type.
If the original series is `int64`, then `replace_with_mask(int64_series, mask, null_array)` fails..."
[ 415.2s] 📖 read_file (narwhals/_arrow/series.py)
[ 415.2s] ✓ {'status': 'ok', 'filepath': 'narwhals/_arrow/series.py', 'content': ' indices_native =
pa.array(indices)\n …
Native result row
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"grade": {
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"status_counts": {
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"strict_clean_patch": true,
"test_exit_code": 0
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"instance_id": "narwhals-dev__narwhals-2864",
"pass_idx": 0,
"patch_chars": 572,
"phase1_seconds": 454.92,
"repo": "narwhals-dev/narwhals",
"request_log_path": "/kaggle-root/working/r31/rollouts_X/requests/narwhals-dev__narwhals-2864__p0__r2.jsonl",
"resolved": true,
"rollout_idx": 2,
"run_key": "narwhals-dev__narwhals-2864__p0__r2",
"strict_clean_patch": true,
"tool_calls": 11,
"total_llm_calls": 11,
"trace_path": "/kaggle-root/working/r31/rollouts_X/traces/trace_narwhals-dev__narwhals-2864__p0__r2.json"
}