Introduce two new Connection::InstanceSource subclasses in PEP249.qll:
- ConnectionGetterAttributeRead: recognises self._conn reads inside
getter methods of classes whose __init__ stores a connect() call in
that attribute. The AttrRead node coincides with the return node, so
the existing TypeTracker returnStep propagates the connection type to
all call sites automatically.
- ConnectionConstructorAttributeRead: recognises ClassName()._conn
direct attribute reads on constructor-call results.
Both classes share the classStoresConnectionInInit helper predicate
that checks for the self.attr = dbapi.connect() store pattern in __init__.
Also adds test cases for the new patterns in the hdbcli test suite
and a change note.
Adds a new `isLazy` predicate to the relevant classes, and adds the
relevant dbscheme (and up/downgrade) changes. On upgrades we do nothing,
and on downgrades we remove the `is_lazy` bits.
This takes care of most of the false negatives from the preceding
commit.
Additionally, we add models for some known wrappers of `socket.socket`
from the `gevent` and `eventlet` packages.
For module-level metaclass declarations, we now also check that the
right hand side in a `__metaclass__ = type` assignment is in fact the
built-in `type`.
These could arguably be moved to `Class` itself, but for now I'm
choosing to limit the changes to the `DuckTyping` module (until we
decide on a proper API).
This module (which for convenience currently resides inside
`DataFlowDispatch`, but this may change later) contains convenience
predicates for bridging the gap between the data-flow layer and the old
points-to analysis.
The fix may look a bit obscure, so here's what's going on.
When we see `from . import helper`, we create an `ImportExpr` with level
equal to 1 (corresponding to the number of dots). To resolve such
imports, we compute the name of the enclosing package, as part of
`ImportExpr.qualifiedTopName()`. For this form of import expression, it
is equivalent to `this.getEnclosingModule().getPackageName()`. But
`qualifiedTopName` requires that `valid_module_name` holds for its
result, and this was _not_ the case for namespace packages.
To fix this, we extend `valid_module_name` to include the module names
of _any_ folder, not just regular package (which are the ones where
there's a `__init__.py` in the folder). Note that this doesn't simply
include all folders -- only the ones that result in valid module names
in Python.
