Extends our modelling to partially cover the behaviour of
`copy.replace`. In particular, we model this in two ways:
Firstly, we extend the existing Models-as-Data row for `copy` and
`deepcopy` to also cover `replace`. This means that we treat the result
of `replace` as containing all of the fields of the original object.
This is somewhat _more_ than we want, as strictly speaking the fields
that are overwritten should _not_ propagate flow through the `replace`
call, but currently we don't have a good way of modelling this blocking
of flow.
Secondly, we add a flow summary that adds flow from named arguments of
the `replace` call to the corresponding fields on the base object. This
ensures that we at least have the new flow arising from the `replace`
call.
Note that the flow summary adds this flow for _all_ named arguments of
_all_ `replace` calls throughout the codebase. However, since any
particular `replace` call will only populate a subset of these (the
subset consisting of exactly those named arguments that are in that
particular call), this does not cause any unwanted crosstalk between
different `replace` calls.§
Demonstrates the somewhat more ergonomic way to use
`getMaDRepresentation` when specifying summaries.
Note that this slightly extends the previous definition, in that
`DictionaryContentAny` is now _also_ propagated by a call to the
`.copy()` method, but I think this is correct.
This adds a convenient way of getting the Models-as-Data representation
of a particular type of content. This avoids repeating the same
construction over and over in our various summaries. Currently this is
defined for all types of content except the captured variable content,
which to my knowledge doesn't have any representation in Models-as-Data.
This test demonstrates the current state of affairs: that `copy.replace`
essentially blocks all flow of taint through it, because it has not been
modelled yet.
Adds up- and downgrade scripts for the support for type parameter
defaults.
In the upgrade direction we do nothing, matching the behaviour of
`getDefault` not having a result for old databases.
In the downgrade direction, we explicitly remove the relevant child (via
the `py_exprs` database relation) for `TypeVar`, `TypeVarTuple`, and
`ParamSpec` parameters.
