unclecode/crawl4ai · error · AttributeError

Setting '{name}' is deprecated. {self._UNWANTED_PROPS[name]}

Error message

Setting '{name}' is deprecated. {self._UNWANTED_PROPS[name]}

What it means

AttributeError from CrawlerRunConfig.__setattr__: assigning to a _UNWANTED_PROPS name is rejected unless the assigned value equals the __init__ default for that parameter (which lets internal default assignment pass). The message carries the migration hint.

Source

Thrown at crawl4ai/async_configs.py:2055:1042

        
        # Experimental Parameters
        self.experimental = experimental or {}


    def __getattr__(self, name):
        """Handle attribute access."""
        if name in self._UNWANTED_PROPS:
            raise AttributeError(f"Getting '{name}' is deprecated. {self._UNWANTED_PROPS[name]}")
        raise AttributeError(f"'{self.__class__.__name__}' has no attribute '{name}'")

    def __setattr__(self, name, value):
        """Handle attribute setting."""
        # TODO: Planning to set properties dynamically based on the __init__ signature
        sig = inspect.signature(self.__init__)
        all_params = sig.parameters  # Dictionary of parameter names and their details

        if name in self._UNWANTED_PROPS and value is not all_params[name].default:
            raise AttributeError(f"Setting '{name}' is deprecated. {self._UNWANTED_PROPS[name]}")
        
        super().__setattr__(name, value)

    @staticmethod
    def from_kwargs(kwargs: dict) -> "CrawlerRunConfig":
        return CrawlerRunConfig(
            # Content Processing Parameters
            word_count_threshold=kwargs.get("word_count_threshold", 200),
            extraction_strategy=kwargs.get("extraction_strategy"),
            chunking_strategy=kwargs.get("chunking_strategy", RegexChunking()),
            markdown_generator=kwargs.get("markdown_generator"),
            only_text=kwargs.get("only_text", False),
            css_selector=kwargs.get("css_selector"),
            target_elements=kwargs.get("target_elements", []),
            excluded_tags=kwargs.get("excluded_tags", []),
            excluded_selector=kwargs.get("excluded_selector", ""),
            keep_data_attributes=kwargs.get("keep_data_attributes", False),
            keep_attrs=kwargs.get("keep_attrs", []),

View on GitHub (pinned to 7e80152142)

Solutions

1. Pass the option in the CrawlerRunConfig(...) constructor using its current name instead of assigning after creation
2. Delete stale keys before restoring persisted configs: {k: v for k, v in saved.items() if k not in DEPRECATED_NAMES}
3. Follow the migration hint in the error message to find the new attribute
4. Catch AttributeError around config restore to detect legacy payloads early and re-map them

Example fix

# before
config = CrawlerRunConfig()
config.old_option = True  # AttributeError: deprecated

# after
config = CrawlerRunConfig(new_option=True)

import inspect
sig = inspect.signature(CrawlerRunConfig.__init__)
allowed = set(sig.parameters) - set(CrawlerRunConfig._UNWANTED_PROPS)
payload = {k: v for k, v in saved_config.items() if k in allowed}
config = CrawlerRunConfig(**payload)  # construct, don't setattr

def is_assignable_config_key(name: str) -> bool:
    return name not in CrawlerRunConfig._UNWANTED_PROPS

try:
    setattr(config, name, value)
except AttributeError as e:
    if "deprecated" in str(e):
        new_key = MIGRATION_MAP[name]
        config = CrawlerRunConfig(**{**asdict_like(config), new_key: value})
    else:
        raise

When it happens

Trigger: config = CrawlerRunConfig(); then config.<removed prop> = value for any deprecated name with a non-default value; dynamic frameworks (dataclasses, ORMs, serializers) that setattr every field of a loaded object also trip this when the object carries a legacy key.

Common situations: Post-construction mutation of config with old attribute names after a version upgrade; deserializing a saved/persisted CrawlerRunConfig from an older crawl4ai; framework __setstate__-style restoration that replays legacy fields.

Related errors

• Getting '{name}' is deprecated. {self._UNWANTED_PROPS[name]}
• Getting '{name}' is deprecated. {self._UNWANTED_PROPS[name]}
• Setting '{name}' is deprecated. {self._UNWANTED_PROPS[name]}
• extraction_strategy must be an instance of ExtractionStrateg
• chunking_strategy must be an instance of ChunkingStrategy

AI-assisted analysis of unclecode/crawl4ai@7e80152142 (2026-08-14). Data as JSON: /api/errors/bc642138a7ab7c69. Report an issue: GitHub.