Model for list.append not working in version 0.9.23

[draftyfrog]

Pysa Bug

Pre-submission checklist
[x] I've checked the list of common issues and mine does not appear

Bug description
I have a model to trace taint along lists, just as described in #163 Tainted lists.

def list.append(self, data: TaintInTaintOut[Updates[self]]): ...

This worked up until including pyre-check Version: 0.9.22. But now with version 0.9.23 I get the following error message:

general.pysa:2:0 Model signature parameters for `list.append` do not match implementation `(list[_T], _T) -> None`. Reason: unexpected named parameter: `self`.

What can I do to make this work again?

[arthaud]

Hi @draftyfrog, thanks for reaching out.

If you look at typeshed, this is how list.append is defined:

pyre-check/stubs/typeshed/typeshed/stdlib/builtins.pyi

Line 1030 in d87b260

def append(self, object: _T, /) -> None: ...

The additional / means that parameters up until that point are unnamed, i.e x.append(object=1) will not work.
You need to make the taint stub match the signature:

def list.append(self, data: TaintInTaintOut[Updates[self]], /): ...

Note that by default, pysa should include the stubs/taint directory, which already includes that model (in a more precise version):

pyre-check/stubs/taint/common/collection_propagation.pysa

Line 131 in d87b260

def list.append(self, object: TaintInTaintOut[Updates[self], UpdatePath[_.all()], NoCollapse], /): ...