[jsonschema.py:_field_docs_for] Regex gets incorrect matches

[mickmis]

(initially reported here)

The doc_pattern regex is supposed (IIUC) to capture the docstrings of the class attributes:

implicitdict/src/implicitdict/jsonschema.py

Line 200 in a137d9e

doc_pattern = r"\n\s+([_a-zA-Z][_a-zA-Z0-9]*)(?:: [^\n]+)?\n(\s+)(?:\"\"\"|''')((?:.|\s)*?)(?:\"\"\"|''')"

However some docstrings specifically formed might be incorrectly captured by this regex, which results in the call to finditer to hang indefinitely.

Here is a minimal example reproducing this issue:

class Query(ImplicitDict):

    participant_id: Optional[str]
    """If specified, identifier of the USS/participant hosting the server involved in this query."""

    def parse_json_result(self, parse_type: Type[ResponseType]) -> ResponseType:
        """Parses the JSON result into the specified type.

        Args:
            parse_type: ImplicitDict type to parse into.
        Returns:
             the parsed response (of type `parse_type`).
        Raises:
            QueryError: if the parsing failed.
        """
        try:
            return parse_type(ImplicitDict.parse(self.response.json, parse_type))
        except (ValueError, TypeError, KeyError) as e:
            raise QueryError(
                f"Parsing JSON response into type {parse_type.__name__} failed with exception {type(e).__name__}: {e}",
                self,
            )


class QueryError(RuntimeError):
    """Error encountered when interacting with a server in the UTM ecosystem."""

    queries: List[Query]

A workaround in the previous example would be to add e.g. a * before QueryError.

This issue can be easily highlighted using e.g. https://regex101.com and:

• selecting Python flavor
• copying the above example as the test string
• copying the faulty regex:

\n\s+([_a-zA-Z][_a-zA-Z0-9]*)(?:: [^\n]+)?\n(\s+)(?:\"\"\"|''')((?:.|\s)*?)(?:\"\"\"|''')

• we then see that participant_id is correctly caught, while QueryError is incorrectly caught as a class attribute with a docstring