# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1476903924 -7200
# Node ID 5952ffef127e4fe40e5a9c517a25d5d26f8bc528
# Parent  aff9bdfadd3fc35f3602bab2a64bc603797369cc
Track assignment and invocation within attribute chains more thoroughly.
Record assignments affecting the whole attribute chain, not just immediate
assignments.

diff -r aff9bdfadd3f -r 5952ffef127e common.py
--- a/common.py	Wed Oct 19 16:37:01 2016 +0200
+++ b/common.py	Wed Oct 19 21:05:24 2016 +0200
@@ -559,7 +559,7 @@
         # Break attribute chains where non-access nodes are found.
 
         if not self.have_access_expression(n):
-            self.attrs = []
+            self.reset_attribute_chain()
 
         # Descend into the expression, extending backwards any existing chain,
         # or building another for the expression.
@@ -568,7 +568,8 @@
 
         # Restore chain information applying to this node.
 
-        self.attrs = attrs
+        if not self.have_access_expression(n):
+            self.restore_attribute_chain(attrs)
 
         # Return immediately if the expression was another access and thus a
         # continuation backwards along the chain. The above processing will
@@ -579,6 +580,18 @@
 
         return name_ref
 
+    def reset_attribute_chain(self):
+
+        "Reset the attribute chain for a subexpression of an attribute access."
+
+        self.attrs = []
+
+    def restore_attribute_chain(self, attrs):
+
+        "Restore the attribute chain for an attribute access."
+
+        self.attrs = attrs
+
     def have_access_expression(self, node):
 
         "Return whether the expression associated with 'node' is Getattr."
diff -r aff9bdfadd3f -r 5952ffef127e inspector.py
--- a/inspector.py	Wed Oct 19 16:37:01 2016 +0200
+++ b/inspector.py	Wed Oct 19 21:05:24 2016 +0200
@@ -21,7 +21,7 @@
 """
 
 from branching import BranchTracker
-from common import get_argnames, init_item, predefined_constants
+from common import CommonModule, get_argnames, init_item, predefined_constants
 from modules import BasicModule, CacheWritingModule, InspectionNaming
 from errors import InspectError
 from referencing import Reference
@@ -45,6 +45,14 @@
         self.in_class = False
         self.in_conditional = False
         self.in_invocation = False
+
+        # Attribute chain state management.
+
+        self.chain_assignment = []
+        self.chain_invocation = []
+
+        # Accesses to global attributes.
+
         self.global_attr_accesses = {}
 
         # Usage tracking.
@@ -367,20 +375,10 @@
 
         "Process the given attribute access node 'n'."
 
-        # Parts of the attribute chain are neither invoked nor assigned.
-
-        in_invocation = self.in_invocation
-        self.in_invocation = False
-        in_assignment = self.in_assignment
-        self.in_assignment = False
-
         # Obtain any completed chain and return the reference to it.
 
         name_ref = self.process_attribute_chain(n)
 
-        self.in_invocation = in_invocation
-        self.in_assignment = in_assignment
-
         if self.have_access_expression(n):
             return name_ref
 
@@ -455,15 +453,14 @@
             # Record attribute usage in the tracker, and record the branch
             # information for the access.
 
-            branches = tracker.use_attribute(name, attrname, self.in_invocation,
-                self.in_assignment and immediate_access)
+            branches = tracker.use_attribute(name, attrname, self.in_invocation, assignment)
 
             if not branches:
                 raise InspectError("Name %s is accessed using %s before an assignment." % (
                     name, attrname), path, n)
 
             self.record_branches_for_access(branches, name, attrnames)
-            access_number = self.record_access_details(name, attrnames, assignment)
+            access_number = self.record_access_details(name, attrnames, self.in_assignment)
 
             del self.attrs[0]
             return AccessRef(name, attrnames, access_number)
@@ -992,6 +989,26 @@
 
         tracker.resume_broken_branches()
 
+    # Attribute chain handling.
+
+    def reset_attribute_chain(self):
+
+        "Reset the attribute chain for a subexpression of an attribute access."
+
+        CommonModule.reset_attribute_chain(self)
+        self.chain_assignment.append(self.in_assignment)
+        self.chain_invocation.append(self.in_invocation)
+        self.in_assignment = False
+        self.in_invocation = False
+
+    def restore_attribute_chain(self, attrs):
+
+        "Restore the attribute chain for an attribute access."
+
+        CommonModule.restore_attribute_chain(self, attrs)
+        self.in_assignment = self.chain_assignment.pop()
+        self.in_invocation = self.chain_invocation.pop()
+
     # Branch tracking methods.
 
     def start_tracking(self, names):