deepset-ai/haystack · error · ValueError

min_effective_lines must not be greater than max_effective_l

Error message

min_effective_lines must not be greater than max_effective_lines.

What it means

PythonCodeSplitter's __init__ enforces min_effective_lines <= max_effective_lines. An inverted range is logically invalid for bounding chunk sizes, so ValueError is raised.

Source

Thrown at haystack/components/preprocessors/python_code_splitter.py:128

        :param strip_docstrings: If ``True``, function/method/class docstrings are moved
            from the chunk content into ``meta["docstrings"]`` (source order). The
            module-level docstring is kept in place since it is itself a top-level unit.
        :param preserve_class_definition: If ``True`` (default), chunks that contain class
            members but not the class header are prefixed with the bare class signature
            (decorators plus the ``class Foo(...):`` lines) in source order.
        :param secondary_split_overlap: Line overlap for the secondary splitter; only used
            in the oversized fallback. The primary AST split never adds overlap.
        :param secondary_split_length: Lines per chunk for the secondary splitter.
            Defaults to ``max_effective_lines`` when ``None``.
        :raises ValueError: If any parameter is invalid (negative, zero where positive is
            required, or ``min_effective_lines > max_effective_lines``).
        """
        if min_effective_lines < 1:
            raise ValueError("min_effective_lines must be at least 1.")
        if max_effective_lines < 1:
            raise ValueError("max_effective_lines must be at least 1.")
        if min_effective_lines > max_effective_lines:
            raise ValueError("min_effective_lines must not be greater than max_effective_lines.")
        if expected_chars_per_line < 1:
            raise ValueError("expected_chars_per_line must be at least 1.")
        if oversized_factor < 1:
            raise ValueError("oversized_factor must be at least 1.")
        if secondary_split_overlap < 0:
            raise ValueError("secondary_split_overlap must be non-negative.")
        if secondary_split_length is not None and secondary_split_length < 1:
            raise ValueError("secondary_split_length must be at least 1.")

        self.min_effective_lines = min_effective_lines
        self.max_effective_lines = max_effective_lines
        self.expected_chars_per_line = expected_chars_per_line
        self.oversized_factor = oversized_factor
        self.strip_docstrings = strip_docstrings
        self.preserve_class_definition = preserve_class_definition
        self.secondary_split_overlap = secondary_split_overlap
        self.secondary_split_length = secondary_split_length

View on GitHub (pinned to e318778c9b)

Solutions

1. Swap or correct the values so min <= max.
2. Add a caller-side check: assert min_effective_lines <= max_effective_lines before construction.
3. Update both bounds together when tuning chunk sizes.
4. Derive one from the other, e.g. max = min * 6, to keep the invariant.

Example fix

// before
PythonCodeSplitter(min_effective_lines=20, max_effective_lines=10)
// after
PythonCodeSplitter(min_effective_lines=5, max_effective_lines=30)

if min_effective_lines > max_effective_lines:
    min_effective_lines, max_effective_lines = max_effective_lines, min_effective_lines

def is_ordered_range(min_l, max_l) -> bool:
    return isinstance(min_l, int) and isinstance(max_l, int) and 1 <= min_l <= max_l

try:
    splitter = PythonCodeSplitter(min_effective_lines=min_l, max_effective_lines=max_l)
except ValueError as e:
    raise ConfigError(f"Invalid line range: {e}") from e

When it happens

Trigger: Calling PythonCodeSplitter(min_effective_lines=20, max_effective_lines=10), or building both from config where the values were swapped or one was updated without the other.

Common situations: Swapped argument order in a positional call, config edits that raised min but not max, or programmatic shrinking of max below an existing min.

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AI-assisted analysis of deepset-ai/haystack@e318778c9b (2026-08-30). Data as JSON: /api/errors/5f3d15b1e3bd01a9. Report an issue: GitHub.