Yes, so basically signature line in help(open) is not shown because ast.parse fails to parse the return value
-> file object
According to grammar, it should be
-> file
or
-> 'file object'
or something like this.
as for sqlite, it fails to parse square brackets:
connect(database[, timeout, detect_types, isolation_level,\n\
check_same_thread, factory, cached_statements, uri])
As an idea, maybe we can come up with a failover i.e. if ast can't parse the signature, just use __text_signature__ instead of signature object:
Lib/pydoc.py:1325
if not argspec:
- argspec = '(...)'
+ argspec = object.__text_signature__
Or probably just don't show the signature if it is not formatted correctly as it is now (after the patch applied).