Also fixes an issue with the return type annotations that caused these
to not work properly.
Currently, annotated assignments don't work properly, due to the fact
that our flow relation doesn't consider flow going to the "type" part of
an annotated assignment. This means that in `x : Foo`, we do correctly
note that `x` is annotated with `Foo`, but we have no idea what `Foo`
is, since it has no incoming flow.
To fix this we should probably just extend the flow relation, but this
may need to be done with some care, so I have left it as future work.
Adds a comment explaining why we no longer flag the indirect tuple
example.
Also adds a test case which _would_ be flagged if not for the type
annotation.
As we're no longer tracking tuples across function boundaries, we lose
the result that related to this setup (which, as the preceding commit
explains, lead to a lot of false positives).
Technically we still depend on points-to in that we still mention
`PythonFunctionValue` and `ClassValue` in the query. However, we
immediately move to working with the corresponding `Function` and
`Class` AST nodes, and so we're not really using points-to. (The reason
for doing things this way is that otherwise the `.toString()` for all of
the alerts would change, which would make the diff hard to interpret.
This way, it should be fairly simple to see which changes are actually
relevant.)
We do lose some precision when moving away from points-to, and this is
reflected in the changes in the `.expected` file. In particular we no
longer do complicated tracking of values, but rather look at the
syntactic structure of the classes in question. This causes us to lose
out on some results where a special method is defined elsewhere, and
causes a single FP where a special method initially has the wrong
signature, but is subsequently overwritten with a function with the
correct signature.
We also lose out on results having to do with default values, as these
are now disabled.
Finally, it was necessary to add special handling of methods marked with
the `staticmethod` decorator, as these expect to receive fewer
arguments. This was motivated by a MRVA run, where e.g. sympy showed a
lot of examples along the lines of
```
@staticmethod
def __abs__():
return ...
```
Fixes the false positive reported in
https://github.com/github/codeql/issues/18910
Adds a new `Annotation` class (subclass of `Expr`) which encompasses all
possible kinds of annotations in Python.
Using this, we look for string literals which are part of an annotation,
and which have the same content as the name of a (potentially) unused
global variable, and in that case we do not produce an alert.
In future, we may want to support inspecting such string literals more
deeply (e.g. to support stuff like "list[unused_var]"), but I think for
now this level of support is sufficient.
Adds two test cases having to do with type annotations. The first one
demonstrates that type annotations (even if they are never executed by
the Python interpreter) count as uses for the purposes of the unused
variable query. The second one demonstrates that this is _not_ the case
if all such uses are inside strings (i.e. forward declarations), as we
do not currently inspect the content of these strings.
Extends the mechanism introduced in
https://github.com/github/codeql/pull/18030
to behave the same for _all_ `MatchLiteralPattern`s, not just the ones
that happen to be the constant `True` or `False`.
Co-authored-by: yoff <yoff@github.com>
Observed on some test files in Nuitka/Nuitka, having `break` and
`continue` outside of loops in Python is (to Python) a syntax error, but
our parser happily accepted this broken syntax.
This then caused issues further downstream in the control-flow
construction, as it broke some invariants.
To fix this we now skip the code that would previously fail when the
invariants are broken.
Co-authored-by: yoff <yoff@github.com>
