Python: Allow CallNode.getArgByName for keyword args after **kwargs

Author: RasmusWL

python/ql/lib/change-notes/2022-09-12-CallNode-getArgByName.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* Changed `CallNode.getArgByName` such that it has results for keyword arguments given after a dictionary unpacking argument, as the `bar=2` argument in `func(foo=1, **kwargs, bar=2)`.

python/ql/lib/semmle/python/Flow.qll

@@ -376,7 +376,7 @@ class CallNode extends ControlFlowNode {
   ControlFlowNode getArgByName(string name) {
     exists(Call c, Keyword k |
       this.getNode() = c and
-      k = c.getAKeyword() and
+      k = c.getANamedArg() and
       k.getValue() = result.getNode() and
       k.getArg() = name and
       result.getBasicBlock().dominates(this.getBasicBlock())

python/ql/test/experimental/dataflow/coverage/argumentPassing.py

@@ -94,7 +94,7 @@ def with_multiple_kw_args(a, b, c):
 def test_multiple_kw_args():
     with_multiple_kw_args(b=arg2, c=arg3, a=arg1)  #$ arg1 arg2 arg3
     with_multiple_kw_args(arg1, *(arg2,), arg3)  #$ arg1 MISSING: arg2 arg3
-    with_multiple_kw_args(arg1, **{"c": arg3}, b=arg2)  #$ arg1 arg3 func=with_multiple_kw_args MISSING: arg2
+    with_multiple_kw_args(arg1, **{"c": arg3}, b=arg2)  #$ arg1 arg2 arg3 func=with_multiple_kw_args MISSING:
     with_multiple_kw_args(**{"b": arg2}, **{"c": arg3}, **{"a": arg1})  #$ arg1 arg2 arg3 func=with_multiple_kw_args