regex format checker crashes with RecursionError on deeply nested patterns

The regex format checker is registered with raises=re.error, but re.compile raises RecursionError (not an re.error subclass) when the pattern nesting exceeds the C stack limit. This causes an uncaught exception to propagate from the validator instead of reporting the instance as invalid.

Reproduction

from jsonschema import Draft202012Validator, FormatChecker

v = Draft202012Validator({"format": "regex"}, format_checker=FormatChecker())
list(v.iter_errors("(" * 500))
# RecursionError: maximum recursion depth exceeded

Expected

The instance should be reported as invalid (not a valid regex), not raise.

Cause

re.compile("(" * 500) raises RecursionError, which is not a subclass of re.error, so FormatChecker.check does not convert it into a FormatError.

This is the same class of issue as the OverflowError case in #1526, but a distinct exception type.

Versions

• jsonschema 4.26.0
• Python 3.13

Start by locating the regex format checker and FormatChecker.check, then reproduce the failure with the deeply nested pattern shown in the issue. The work is done when that input is reported as an invalid regex through a FormatError rather than propagating RecursionError.