SeleniumHQ/selenium · error · ValueError

Autodetect proxy value needs to be a boolean

Error message

Autodetect proxy value needs to be a boolean

What it means

The auto_detect property is backed by _ProxyTypeDescriptor with name 'autodetect', which requires a bool. Assigning any non-bool (string 'true', int 1, None) raises ValueError. Setting auto_detect also flips the proxyType to AUTODETECT via the descriptor.

Source

Thrown at py/selenium/webdriver/common/proxy.py:68

        value = str(value).upper()
        for attr in dir(cls):
            attr_value = getattr(cls, attr)
            if isinstance(attr_value, dict) and "string" in attr_value and attr_value["string"] == value:
                return attr_value
        raise Exception(f"No proxy type is found for {value}")


class _ProxyTypeDescriptor:
    def __init__(self, name, p_type):
        self.name = name
        self.p_type = p_type

    def __get__(self, obj, cls):
        return getattr(obj, self.name)

    def __set__(self, obj, value):
        if self.name == "autodetect" and not isinstance(value, bool):
            raise ValueError("Autodetect proxy value needs to be a boolean")
        getattr(obj, "_verify_proxy_type_compatibility")(self.p_type)
        setattr(obj, "proxyType", self.p_type)
        setattr(obj, self.name, value)


class Proxy:
    """Proxy configuration containing proxy type and necessary proxy settings."""

    proxyType = ProxyType.UNSPECIFIED
    autodetect = False
    httpProxy = ""
    noProxy = ""
    proxyAutoconfigUrl = ""
    sslProxy = ""
    socksProxy = ""
    socksUsername = ""
    socksPassword = ""
    socksVersion = None

View on GitHub (pinned to aa36b38e69)

Solutions

1. Pass a real bool: proxy.auto_detect = True.
2. Convert string config: proxy.auto_detect = (val.lower() == 'true').

Example fix

# before
proxy.auto_detect = 'true'  # str -> ValueError

# after
proxy.auto_detect = True
# from config string
proxy.auto_detect = (config_val.strip().lower() in ('true', '1', 'yes'))

if not isinstance(auto_val, bool):
    auto_val = str(auto_val).strip().lower() in ('true','1','yes')
proxy.auto_detect = auto_val

def is_bool(v) -> bool:
    return isinstance(v, bool)

try:
    proxy.auto_detect = val
except ValueError:
    proxy.auto_detect = bool(val)

When it happens

Trigger: Setting proxy.auto_detect = 'true' (string), proxy.auto_detect = 1, or proxy.auto_detect = 'yes'. Assigning from config/env that yields a string.

Common situations: Loading 'autodetect' from JSON/YAML as a string. Using truthy ints. Environment-variable parsing returning strings.

Related errors

• Only Proxy objects can be passed in.
• `raw` must be a dict, got {type(raw)}
• no_proxy list must contain only strings
• no_proxy must be a comma-separated string or a list of strin
• Please pass in a Boolean to this call

AI-assisted analysis of SeleniumHQ/selenium@aa36b38e69 (2026-08-14). Data as JSON: /api/errors/fc821dfda553682d. Report an issue: GitHub.