BTree_rangeSearch(): Like its bucket counterpart, this wasn't checking

for lo > hi either, except if they happened to be in the same bucket.  All
sorts of strange results followed (the range should be empty if lo > hi,
and is after this patch).

src/BTrees/BTreeTemplate.c

@@ -12,7 +12,7 @@
 
  ****************************************************************************/
 
-#define BTREETEMPLATE_C "$Id: BTreeTemplate.c,v 1.51 2002/06/13 14:06:57 tim_one Exp $\n"
+#define BTREETEMPLATE_C "$Id: BTreeTemplate.c,v 1.52 2002/06/13 20:08:39 tim_one Exp $\n"
 
 /*
 ** _BTree_get
@@ -1123,6 +1123,23 @@ BTree_rangeSearch(BTree *self, PyObject *args, char type)
 
   UNLESS (self->data && self->len) goto empty;
 
+  /* If f and l were both passed in, ensure f <= l. */
+  if (f && f != Py_None && l && l != Py_None)
+    {
+      int cmp;
+      KEY_TYPE first;
+      KEY_TYPE last;
+      int copied = 1;
+
+      COPY_KEY_FROM_ARG(first, f, copied);
+      UNLESS (copied) goto err;
+      COPY_KEY_FROM_ARG(last, l, copied);
+      UNLESS (copied) goto err;
+
+      TEST_KEY_SET_OR(cmp, first, last) goto err;
+      if (cmp > 0) goto empty;
+    }
+
   /* Find the low range */
 
   if (f && f != Py_None)

src/BTrees/tests/testBTrees.py

@@ -251,6 +251,14 @@ class MappingBase(Base):
         self.assertEqual(list(t.keys(10,12)), [], list(t.keys(10,12)))
         self.assertEqual(list(t.keys(9, 1)), [], list(t.keys(9, 1)))
 
+        # For IITreeSets, this one was returning 31 for len(keys), and
+        # list(keys) produced a list with 100 elements.
+        t.clear()
+        t.update(zip(range(300), range(300)))
+        keys = t.keys(200, 50)
+        self.assertEqual(len(keys), 0)
+        self.assertEqual(list(keys), [])
+
     def testSlicing(self):
         # Test that slicing of .keys()/.values()/.items() works exactly the
         # same way as slicing a Python list with the same contents.
@@ -430,6 +438,14 @@ class NormalSetTests(Base):
         self.assertEqual(list(t.keys(10,12)), [], list(t.keys(10,12)))
         self.assertEqual(list(t.keys(9,1)), [], list(t.keys(9,1)))
 
+        # For IITreeSets, this one was returning 31 for len(keys), and
+        # list(keys) produced a list with 100 elements.
+        t.clear()
+        t.update(range(300))
+        keys = t.keys(200, 50)
+        self.assertEqual(len(keys), 0)
+        self.assertEqual(list(keys), [])
+
     def testSlicing(self):
         # Test that slicing of .keys() works exactly the same way as slicing
         # a Python list with the same contents.