.

wcfs/internal/xbtree.py

@@ -487,7 +487,7 @@ def AllStructs(keys, maxdepth, maxsplit, allowEmptyBuckets=False): # -> i[] of T
             yield Tree([], Bucket())
             return
 
-        # XXX ok? (should be -inf,+inf)
+        # XXX ok? (ideally should be -inf,+inf)
         klo = 0
         khi = 0
 
@@ -525,11 +525,14 @@ def _allStructs(klo, khi, keyv, maxdepth, maxsplit, allowEmptyBuckets):
                 continue
             ichildrenv = [] # of _allStructs for each child link
             for (xlo, xhi) in zip(ksplitv[:-1], ksplitv[1:]): # (klo, s1), (s1, s2), ..., (sN, khi)
+                ckeyv = _keyvSliceBy(keyv, xlo, xhi)
+                if len(ckeyv) == 0 and (not allowEmptyBuckets):
+                    break
                 ichildrenv.append( _allStructs(
-                    xlo, xhi, _keyvSliceBy(keyv, xlo, xhi), maxdepth - 1, maxsplit, allowEmptyBuckets))
-
-            for children in itertools.product(*ichildrenv):
-                yield Tree(ksplitv[1:-1], *children) # (s1, s2, ..., sN)
+                    xlo, xhi, ckeyv, maxdepth - 1, maxsplit, allowEmptyBuckets))
+            else:
+                for children in itertools.product(*ichildrenv):
+                    yield Tree(ksplitv[1:-1], *children) # (s1, s2, ..., sN)
 
 
 # _keyvSliceBy returns [] of keys from keyv : k ∈ [klo, khi)