The `Builtins` module is deeply entwined with points-to, so it would be
nice to not have this dependence. Happily, the only thing we used
`Builtin` for was to get the names of known builtins, and for this we
already maintain such a set of names in
`dataflow.new.internal.Builtins`.
For now, these have just been made into `private` imports. After doing
this, I went through all of the (now not compiling) files and added in
private imports to the modules that they actually depended on.
I also added an explicit import of `LegacyPointsTo` (even though it may
be unnecessary) in cases where the points-to dependency was somewhat
surprising (and one we want to get rid of). This was primarily inside
the various SSA layers.
For modules inside `semmle.python.{types, objects, pointsto}` I did not
bother, as these are fairly clearly related to points-to.
Moves the existing points-to predicates to the newly added class
`ControlFlowNodeWithPointsTo` which resides in the `LegacyPointsTo`
module.
(Existing code that uses these predicates should import this module, and
references to `ControlFlowNode` should be changed to
`ControlFlowNodeWithPointsTo`.)
Also updates all existing points-to based code to do just this.
Adds support for tracking instances via type annotations. Also adds a
convenience method to the newly added `Annotation` class,
`getAnnotatedExpression`, that returns the expression that is annotated
with the given type. For return annotations this is any value returned
from the annotated function in question.
Co-authored-by: Napalys Klicius <napalys@github.com>
Adds API graph support for observing that in
```python
def foo(x : Bar): ...
```
The variable `x` is likely to be an instance of the type `Bar` inside
this function.
In particular, we add `getInstanceFromAnnotation` as a predicate on API
graph nodes that tracks this step (corresponding to a new edge type
labeled with "annotation" in the API graph), and extend the existing
`getAnInstance` predicate to also include instances arising from type
annotations.
A more complete solution would also add support for annotated
assignments (`x : Foo = ...` or just `x : Foo`) as well as track types
through type aliases (`type Foo = Bar`). This turns out to be
non-trivial, however, as these type constructs don't have any CFG nodes
(and so no data-flow nodes by default either). In order to not have
perfect be the enemy of good, this commit is only targeting the type
parameter case (which is also likely to be the most common use case
anyway).
The tests for API graphs have been extended accordingly, including tests
for the kinds of type ascriptions that we _don't_ currently model in API
graphs (marked with `MISSING:` in the inline tests).
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.
