# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1258935726 -3600
# Node ID 54a2867eb4651d381769dee67263cfcb9bac2be4
# Parent  4435e910a9d35b290fc2170ba4654fa9ffbc2479
Added attribute usage registration for branches where more specific attribute
usage occurs, but where such usage cannot be merged back into the active usage
definition for a given name. This should ensure that attributes are not
forgotten because their usage was not merged and carried forward.
Added more specific tests.

diff -r 4435e910a9d3 -r 54a2867eb465 micropython/data.py
--- a/micropython/data.py	Sun Nov 22 23:53:30 2009 +0100
+++ b/micropython/data.py	Mon Nov 23 01:22:06 2009 +0100
@@ -374,20 +374,33 @@
     def _merge_branches(self):
         active = self.attributes_used[-1]
 
+        # Take each alternative branch, currently shelved, and find the
+        # intersection of their contributions for each name.
+
         shelved_defs = self.attribute_shelves.pop()
-        defs = shelved_defs[0]
+        defs = dict(shelved_defs[0])
 
         for next_defs in shelved_defs[1:]:
             for name, attrnames in next_defs.items():
                 if defs.has_key(name):
                     defs[name] = defs[name].intersection(attrnames)
 
+        # Intersect the contributions with the previous state for each name.
+
         for name, attrnames in defs.items():
             if active.has_key(name):
                 active[name].intersection_update(attrnames)
             else:
                 active[name] = attrnames
 
+        # Where each shelved set of definitions is a superset of the eventual
+        # definitions for a name, record these specialised sets of usage.
+
+        for defs in shelved_defs:
+            for name, attrnames in defs.items():
+                if attrnames.issuperset(active[name]):
+                    self.all_attributes_used.append(attrnames)
+
 # Program data structures. There are two separate kinds of structures: those
 # with context, which are the values manipulated by programs, and those without
 # context, which are typically constant things which are stored alongside the
diff -r 4435e910a9d3 -r 54a2867eb465 tests/attribute_access_type_restriction.py
--- a/tests/attribute_access_type_restriction.py	Sun Nov 22 23:53:30 2009 +0100
+++ b/tests/attribute_access_type_restriction.py	Mon Nov 23 01:22:06 2009 +0100
@@ -18,15 +18,6 @@
     def h(self):
         return 5
 
-def test_conditional(obj):
-    # obj: C, D, E (f)
-    if obj.f():     # C, D, E (f)
-        obj.g()     # D (f, g)
-    # else:
-    #   ...         # obj: C, D, E (f)
-    #               # (f, g) ^ (f)
-    return 2
-
 def test_new(obj, obj2):
     # obj: C, D, E (f)
     # obj2:
@@ -62,7 +53,6 @@
 c = C()
 d = D()
 e = E()
-result1_2 = test_conditional(d)
 result2_2 = test_new(c, d)
 result1_4 = test_neither(c, d)
 result1_5 = test_new_conditional(e, d)
diff -r 4435e910a9d3 -r 54a2867eb465 tests/attribute_access_type_restriction_conditional.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/attribute_access_type_restriction_conditional.py	Mon Nov 23 01:22:06 2009 +0100
@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+
+class C:
+    def f(self):
+        return 1
+
+class D:
+    def f(self):
+        return 2
+
+    def g(self):
+        return 3
+
+class E:
+    def f(self):
+        return 4
+
+    def h(self):
+        return 5
+
+def test_conditional(obj):
+    # obj: C, D, E (f)
+    if obj.f():     # C, D, E (f)
+        obj.g()     # D (f, g)
+    # else:
+    #   ...         # obj: C, D, E (f)
+    #               # (f, g) ^ (f)
+    return 2
+
+c = C()
+d = D()
+e = E()
+result1_2 = test_conditional(d)
+
+# vim: tabstop=4 expandtab shiftwidth=4
diff -r 4435e910a9d3 -r 54a2867eb465 tests/attribute_access_type_restriction_conditional_choice.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/attribute_access_type_restriction_conditional_choice.py	Mon Nov 23 01:22:06 2009 +0100
@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+
+class C:
+    def f(self):
+        return 1
+
+class D:
+    def f(self):
+        return 2
+
+    def g(self):
+        return 3
+
+class E:
+    def f(self):
+        return 4
+
+    def h(self):
+        return 5
+
+def test_conditional(obj):
+    # obj: C, D, E (f)
+    if obj.f():     # C, D, E (f)
+        obj.g()     # D (f, g)
+    else:
+        obj.h()     # E (f, h)
+    #               # (f, g) ^ (f, h)
+    return 2
+
+c = C()
+d = D()
+e = E()
+result1_2 = test_conditional(d)
+
+# vim: tabstop=4 expandtab shiftwidth=4