Patched code sample

import html.parser
import sys

class SafeHTMLParser(html.parser.HTMLParser):
    def __init__(self, *args, max_input_length=100000, **kwargs):
        super().__init__(*args, **kwargs)
        self.max_input_length = max_input_length
        self.data_buffer = []

    def feed(self, data):
        if len(data) > self.max_input_length:
            raise ValueError(f"Input exceeds maximum allowed length of {self.max_input_length}")
        super().feed(data)

    def handle_starttag(self, tag, attrs):
        # Process start tag.  This example limits the number of attributes.
        if len(attrs) > 10:  # Example limit: max 10 attributes
            raise ValueError("Too many attributes in start tag")
        # Additional tag-specific handling and length checks for attribute values can be implemented here.
        # Example: limit length of attribute values
        for attr_name, attr_value in attrs:
            if len(attr_value) > 200: # Example limit: max length of 200 for attribute value
                raise ValueError(f"Attribute value for {attr_name} too long")

    def handle_data(self, data):
        # Process data within tags. This addresses potential exponential behavior when constructing the data string
        self.data_buffer.append(data)
        if sum(len(s) for s in self.data_buffer) > self.max_input_length:
             raise ValueError("Data content exceeds maximum allowed length")

    def close(self):
        # Process accumulated data efficiently
        full_data = "".join(self.data_buffer)
        # Do something with full_data, e.g., check against a blacklist
        if len(full_data) > self.max_input_length:
            raise ValueError("Processed data exceeds maximum allowed length after combination.")
        super().close() # ensures closing logic is called.

def safe_parse_html(html_string, max_length=100000):
    """Safely parses HTML with length limits and other constraints."""
    parser = SafeHTMLParser(max_input_length=max_length)
    try:
        parser.feed(html_string)
        parser.close()
    except ValueError as e:
        print(f"Parsing error: {e}", file=sys.stderr)
        return None  # Or raise the exception, depending on desired behavior
    except Exception as e:
        print(f"Unexpected parsing error: {e}", file=sys.stderr)
        return None # Or raise
    return parser # return the parser if you want to inspect its attributes.  Otherwise, return relevant data