rohitg00/ai-engineering-from-scratch · error · ValueError

pattern must be a string

Error message

pattern must be a string

What it means

Error "pattern must be a string" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/21-tool-registry-schema-validation/code/main.py:136

    t = schema.get("type")
    if t is not None and t not in PRIMITIVE_TYPE_MAP:
        raise ValueError(f"unsupported type: {t!r}")
    enum_vals = schema.get("enum")
    if enum_vals is not None and not isinstance(enum_vals, list):
        raise ValueError("enum must be a list")
    min_len = schema.get("minLength")
    if min_len is not None:
        if isinstance(min_len, bool) or not isinstance(min_len, int) or min_len < 0:
            raise ValueError("minLength must be a non-negative integer")
    max_len = schema.get("maxLength")
    if max_len is not None:
        if isinstance(max_len, bool) or not isinstance(max_len, int) or max_len < 0:
            raise ValueError("maxLength must be a non-negative integer")
    if min_len is not None and max_len is not None and min_len > max_len:
        raise ValueError("minLength cannot be greater than maxLength")
    pattern = schema.get("pattern")
    if pattern is not None and not isinstance(pattern, str):
        raise ValueError("pattern must be a string")
    props = schema.get("properties")
    if props is not None:
        if not isinstance(props, dict):
            raise ValueError("properties must be a dict")
        for pname, psub in props.items():
            if not isinstance(pname, str):
                raise ValueError("property names must be strings")
            validate_schema_shape(psub)
    items = schema.get("items")
    if items is not None:
        validate_schema_shape(items)
    req = schema.get("required")
    if req is not None:
        if not isinstance(req, list) or not all(isinstance(x, str) for x in req):
            raise ValueError("required must be list[str]")


def _path(prefix: str, segment: str | int) -> str:

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/21-tool-registry-schema-validation/code/main.py:136 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/0476142eebdde83e. Report an issue: GitHub.