# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1486567227 -3600
# Node ID aa11ebd14c79eac3a5bcda5c18d8593f0aaa665d
# Parent  e8e4490ac9d40c80f1b630b3623d4d02d29fba5b
Incorporated keyword arguments into invocation descriptions so that argument
compatibility can be more broadly tested and restrict accesses accordingly.

diff -r e8e4490ac9d4 -r aa11ebd14c79 deducer.py
--- a/deducer.py	Wed Feb 08 01:21:39 2017 +0100
+++ b/deducer.py	Wed Feb 08 16:20:27 2017 +0100
@@ -1863,8 +1863,8 @@
         'object_type' identified by 'ref' is compatible with any arguments used.
         """
 
-        arguments = self.reference_invocations.get(location)
-        if arguments is None:
+        invocation = self.reference_invocations.get(location)
+        if invocation is None:
             return True
 
         objpath = ref.get_origin()
@@ -1876,12 +1876,15 @@
             return True
 
         defaults = self.importer.function_defaults.get(objpath)
+        arguments, keywords = invocation
+        names = set(parameters)
 
         # Determine whether the specified arguments are
         # compatible with the callable signature.
 
         if arguments >= len(parameters) - len(defaults) and \
-           arguments <= len(parameters):
+           arguments <= len(parameters) and \
+           names.issuperset(keywords):
 
             return True
         else:
diff -r e8e4490ac9d4 -r aa11ebd14c79 encoders.py
--- a/encoders.py	Wed Feb 08 01:21:39 2017 +0100
+++ b/encoders.py	Wed Feb 08 16:20:27 2017 +0100
@@ -93,7 +93,8 @@
     if assignment:
         return "="
     elif invocation is not None:
-        return "(%d)" % invocation
+        arguments, keywords = invocation
+        return "(%d;%s)" % (arguments, ",".join(keywords))
     else:
         return "_"
 
@@ -111,8 +112,13 @@
             modifiers.append((True, None))
             i += 1
         elif s[i] == "(":
+            j = s.index(";", i)
+            arguments = int(s[i+1:j])
+            i = j
             j = s.index(")", i)
-            modifiers.append((False, int(s[i+1:j])))
+            keywords = s[i+1:j]
+            keywords = keywords and keywords.split(",") or []
+            modifiers.append((False, (arguments, keywords)))
             i = j + 1
         else:
             modifiers.append((False, None))
diff -r e8e4490ac9d4 -r aa11ebd14c79 inspector.py
--- a/inspector.py	Wed Feb 08 01:21:39 2017 +0100
+++ b/inspector.py	Wed Feb 08 16:20:27 2017 +0100
@@ -438,7 +438,8 @@
             # Record attribute usage in the tracker, and record the branch
             # information for the access.
 
-            branches = tracker.use_attribute(name, attrname, self.in_invocation is not None, assignment)
+            branches = tracker.use_attribute(name, attrname,
+                self.in_invocation is not None, assignment)
 
             if not branches:
                 raise InspectError("Name %s is accessed using %s before an assignment." % (
@@ -742,22 +743,29 @@
         self.allocate_arguments(path, n.args)
 
         try:
+            in_invocation = self.in_invocation
+            self.in_invocation = None
+
+            # Process the arguments.
+
+            keywords = set()
+
+            for arg in n.args:
+                self.process_structure_node(arg)
+                if isinstance(arg, compiler.ast.Keyword):
+                    keywords.add(arg.name)
+
+            keywords = list(keywords)
+            keywords.sort()
+
             # Communicate to the invocation target expression that it forms the
             # target of an invocation, potentially affecting attribute accesses.
 
-            in_invocation = self.in_invocation
-            self.in_invocation = len(n.args)
+            self.in_invocation = len(n.args), keywords
 
             # Process the expression, obtaining any identified reference.
 
             name_ref = self.process_structure_node(n.node)
-            self.in_invocation = None
-
-            # Process the arguments.
-
-            for arg in n.args:
-                self.process_structure_node(arg)
-
             self.in_invocation = in_invocation
 
             # Detect class invocations.
diff -r e8e4490ac9d4 -r aa11ebd14c79 tests/keyword_args.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/keyword_args.py	Wed Feb 08 16:20:27 2017 +0100
@@ -0,0 +1,24 @@
+class C:
+    def f(self, x, y, z):
+        return z
+
+class D:
+    def f(self, a, b, c):
+        return c
+
+def xyz(obj):
+    return obj.f(1, 2, z=3)
+
+def abc(obj):
+    return obj.f(4, 5, c=6)
+
+c = C()
+d = D()
+
+print xyz(c)                    # 3
+print abc(d)                    # 6
+
+try:
+    print xyz(d)                # should raise an exception
+except TypeError:
+    print "xyz(d): argument cannot be used"
diff -r e8e4490ac9d4 -r aa11ebd14c79 tests/keyword_args_bad.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/keyword_args_bad.py	Wed Feb 08 16:20:27 2017 +0100
@@ -0,0 +1,15 @@
+class C:
+    def f(self, x, y, z):
+        return z
+
+class D:
+    def f(self, a, b, c):
+        return c
+
+def pqr(obj):
+    return obj.f(1, 2, r=3)     # no corresponding function
+
+c = C()
+d = D()
+
+print pqr(c)                    # should fail