Make module-level 'aq_acquire' respect 'default'.

Fixes LP #1387363.

CHANGES.txt

@@ -4,6 +4,9 @@ Changelog
 4.0.1 (unreleased)
 ------------------
 
+- Make module-level ``aq_acquire`` API respect the ``default`` parameter.
+  LP #1387363.
+
 - Don't raise an attribute error for ``__iter__`` if the fallback to
   ``__getitem__`` succeeds.  LP #1155760.
 

src/Acquisition/_Acquisition.c

@@ -1499,12 +1499,14 @@ capi_aq_acquire(PyObject *self, PyObject *name, PyObject *filter,
   if (filter==Py_None) filter=0;
 
   /* We got a wrapped object, so business as usual */
-  if (isWrapper(self)) 
-    return Wrapper_findattr(
+  if (isWrapper(self)) {
+    result = Wrapper_findattr(
 	      WRAPPER(self), name, filter, extra, OBJECT(self),1,
 	      explicit || 
 	      WRAPPER(self)->ob_type==(PyTypeObject*)&Wrappertype,
 	      explicit, containment);  
+    goto check_default;
+  }
   /* Not wrapped; check if we have a __parent__ pointer.  If that's
      the case, create a wrapper and pretend it's business as usual. */
   else if ((result = PyObject_GetAttr(self, py__parent__)))
@@ -1515,7 +1517,7 @@ capi_aq_acquire(PyObject *self, PyObject *name, PyObject *filter,
                                 OBJECT(self), 1, 1, explicit, containment);
       /* Get rid of temporary wrapper */
       Py_DECREF(self);
-      return result;
+      goto check_default;
     }
   /* No wrapper and no __parent__, so just getattr. */
   else
@@ -1530,7 +1532,10 @@ capi_aq_acquire(PyObject *self, PyObject *name, PyObject *filter,
         }
       Py_XDECREF(result); Py_XDECREF(v); Py_XDECREF(tb);
 
-      if (! filter) return PyObject_GetAttr(self, name);
+      if (! filter) {
+        result = PyObject_GetAttr(self, name);
+        goto check_default;
+      }
 
       /* Crap, we've got to construct a wrapper so we can use
          Wrapper_findattr */
@@ -1542,8 +1547,22 @@ capi_aq_acquire(PyObject *self, PyObject *name, PyObject *filter,
 
       /* Get rid of temporary wrapper */
       Py_DECREF(self);
-      return result;
+      goto check_default;
     }
+check_default:
+    if (result == NULL && defalt != NULL) {
+      /* as "Python/bltinmodule.c:builtin_getattr" turn
+        only 'AttributeError' into a default value, such
+        that e.g. "ConflictError" and errors raised by the filter
+        are not mapped to the default value.
+      */
+      if (PyErr_ExceptionMatches(PyExc_AttributeError)) {
+        PyErr_Clear();
+        Py_INCREF(defalt);
+        result = defalt;
+      }
+    }
+    return result;
 }
 
 static PyObject *

src/Acquisition/tests.py

@@ -2527,6 +2527,9 @@ class TestAcquire(unittest.TestCase):
     def test_explicit_wrapper_false(self):
         self.assertEqual(self.a.b.c.aq_acquire('z', explicit=False), 3)
 
+    def test_falls_back_to_default(self):
+        self.assertEqual(self.acquire(object(), 'nonesuch', default=4), 4)
+
 
 class TestUnicode(unittest.TestCase):