some understanding of the __builtin__.property decorator

5 files changed, 83 insertions, 25 deletions

diff --git a/ChangeLog b/ChangeLog
index f0ebf73c..993486a1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,8 +1,12 @@
 Change log for the astng package
 ================================
 
+--
+    * some understanding of the __builtin__.property decorator
+	
 2009-03-19  -- 0.18.0
-    * major api / tree structure changes to make it works with compiler *and* py >= 2.5 _ast module
+    * major api / tree structure changes to make it works with compiler *and*
+      python >= 2.5 _ast module
     * cleanups and refactoring on the way
 
 	
diff --git a/infutils.py b/infutils.py
index 26019f5a..f22ad714 100644
--- a/infutils.py
+++ b/infutils.py
@@ -256,26 +256,28 @@ class Instance(Proxy):
         try:
             # XXX frame should be self._proxied, or not ?
             return _infer_stmts(
-                self._wrap_attr(self.getattr(name, context, lookupclass=False)),
+                self._wrap_attr(self.getattr(name, context, lookupclass=False), context),
                                 context, frame=self)
         except NotFoundError:
             try:
                 # fallback to class'igetattr since it has some logic to handle
                 # descriptors
-                return self._wrap_attr(self._proxied.igetattr(name, context))
+                return self._wrap_attr(self._proxied.igetattr(name, context), context)
             except NotFoundError:
                 raise InferenceError(name)
             
-    def _wrap_attr(self, attrs):
+    def _wrap_attr(self, attrs, context=None):
         """wrap bound methods of attrs in a InstanceMethod proxies"""
-        # Guess which attrs are used in inference.
-        def wrap(attr):
-            if isinstance(attr, Function) and attr.type == 'method':
-                return InstanceMethod(attr)
+        for attr in attrs:
+            if isinstance(attr, Function):
+                if '__builtin__.property' in attr.decoratornames():
+                    for infered in attr.infer_call_result(self, context):
+                        yield infered
+                elif attr.type == 'method':
+                    yield InstanceMethod(attr)
             else:
-                return attr
-        return imap(wrap, attrs)
-        
+                yield attr
+
     def infer_call_result(self, caller, context=None):
         """infer what's a class instance is returning when called"""
         infered = False
diff --git a/rebuilder.py b/rebuilder.py
index 80ec28cb..90047215 100644
--- a/rebuilder.py
+++ b/rebuilder.py
@@ -130,18 +130,22 @@ class RebuildVisitor(ASTVisitor):
     def leave_assign(self, node):
         """leave an Assign node to become astng"""
         klass = node.parent.frame()
-        if isinstance(klass, nodes.Class) and \
-            isinstance(node.value, nodes.CallFunc) and \
-            isinstance(node.value.func, nodes.Name):
+        if (isinstance(klass, nodes.Class)
+            and isinstance(node.value, nodes.CallFunc)
+            and isinstance(node.value.func, nodes.Name)):
             func_name = node.value.func.name
-            if func_name in ('classmethod', 'staticmethod'):
-                for ass_node in node.targets:
-                    try:
-                        meth = klass[ass_node.name]
-                        if isinstance(meth, nodes.Function):
+            for ass_node in node.targets:
+                try:
+                    meth = klass[ass_node.name]
+                    if isinstance(meth, nodes.Function):
+                        if func_name in ('classmethod', 'staticmethod'):
                             meth.type = func_name
-                    except (AttributeError, KeyError):
-                        continue
+                        try:
+                            meth.extra_decorators.append(node.value)
+                        except AttributeError:
+                            meth.extra_decorators = [node.value]
+                except (AttributeError, KeyError):
+                    continue
         elif getattr(node.targets[0], 'name', None) == '__metaclass__': # XXX check more...
             self._metaclass[-1] = 'type' # XXX get the actual metaclass
 
diff --git a/scoped_nodes.py b/scoped_nodes.py
index e42d3cee..fa1f6dae 100644
--- a/scoped_nodes.py
+++ b/scoped_nodes.py
@@ -31,6 +31,7 @@ __doctype__ = "restructuredtext en"
 import sys
 
 from logilab.common.compat import chain, set
+from logilab.common.decorators import cached
 
 from logilab.astng import MANAGER, NotFoundError, NoDefault, \
      ASTNGBuildingException, InferenceError
@@ -378,8 +379,21 @@ class FunctionNG(object):
         # (eg pylint...) when is_method() return True
         return self.type != 'function' and isinstance(self.parent.frame(), Class)
 
+    @cached
+    def decoratornames(self):
+        """return a list of decorator qualified names"""
+        result = set()
+        decoratornodes = []
+        if self.decorators is not None:
+            decoratornodes += self.decorators.nodes
+        decoratornodes += getattr(self, 'extra_decorators', [])
+        for decnode in decoratornodes:
+            for infnode in decnode.infer():
+                result.add(infnode.qname())
+        return result
+    
     def argnames(self):
-        """return argument names if there are any arguments"""
+        """return a list of argument names"""
         if self.args.args: # maybe None with builtin functions
             names = _rec_get_names(self.args.args)
         else:
diff --git a/test/unittest_inference.py b/test/unittest_inference.py
index e91efa14..9131769b 100644
--- a/test/unittest_inference.py
+++ b/test/unittest_inference.py
@@ -870,20 +870,20 @@ def f(x):
         if sys.version_info < (2, 5):
             self.skip('require py >= 2.5')
         data = "from ...common import date; print date"
-        astng = builder.string_build(data, 'logilab.astng.test.unittest_inference', __file__)
+        astng = builder.string_build(data, __name__, __file__)
         infered = get_name_node(astng, 'date').infer().next()
         self.assertIsInstance(infered, nodes.Module)
         self.assertEquals(infered.name, 'logilab.common.date')
 
     def test_python25_no_relative_import(self):
         data = 'import unittest_lookup; print unittest_lookup'
-        astng = builder.string_build(data, 'logilab.astng.test.unittest_inference', __file__)
+        astng = builder.string_build(data, __name__, __file__)
         self.failIf(astng.absolute_import_activated())
 #         infered = get_name_node(astng, 'unittest_lookup').infer().next()
 #         self.assertIsInstance(infered, nodes.Module)
         # failed to import unittest_lookup since absolute_import is activated
         data = 'from __future__ import absolute_import; import unittest_lookup; print unittest_lookup'
-        astng = builder.string_build(data, 'logilab.astng.test.unittest_inference', __file__)
+        astng = builder.string_build(data, __name__, __file__)
         self.failUnless(astng.absolute_import_activated(), True)
 #         infered = get_name_node(astng, 'unittest_lookup').infer().next()
 #         # failed to import unittest_lookup since absolute_import is activated
@@ -914,6 +914,40 @@ def f(x):
 #         self.assertEquals(len(bopen), 1)
 #         self.assertIsInstance(bopen[0], InstanceMethod)
 #         self.failUnless(bopen[0].callable())
+
+    def test_property(self):
+        code = '''
+from smtplib import SMTP
+class SendMailController(object):
+
+    @property
+    def smtp(self):
+        return SMTP(mailhost, port)
+    
+    @property
+    def me(self):
+        return self
     
+print SendMailController().smtp
+print SendMailController().me
+'''
+        astng = builder.string_build(code, __name__, __file__)
+        self.assertEquals(astng['SendMailController']['smtp'].decoratornames(),
+                          set(('__builtin__.property',)))
+        propinfered = list(astng.body[2].values[0].infer())
+        self.assertEquals(len(propinfered), 1)
+        propinfered = propinfered[0]
+        self.assertIsInstance(propinfered, Instance)
+        self.assertEquals(propinfered.name, 'SMTP')
+        self.assertEquals(propinfered.root().name, 'smtplib')
+        self.assertEquals(astng['SendMailController']['me'].decoratornames(),
+                          set(('__builtin__.property',)))
+        propinfered = list(astng.body[3].values[0].infer())
+        self.assertEquals(len(propinfered), 1)
+        propinfered = propinfered[0]
+        self.assertIsInstance(propinfered, Instance)
+        self.assertEquals(propinfered.name, 'SendMailController')
+        self.assertEquals(propinfered.root().name, __name__)
+        
 if __name__ == '__main__':
     unittest_main()