Issue 13274: Make the pure python code for heapq more closely match the C implementation for an undefined corner case.

1 files changed, 4 insertions, 0 deletions

diff --git a/Lib/heapq.py b/Lib/heapq.py
index fcaca13..6a4e0f4 100644
--- a/Lib/heapq.py
+++ b/Lib/heapq.py
@@ -193,6 +193,8 @@ def nlargest(n, iterable):
 
     Equivalent to:  sorted(iterable, reverse=True)[:n]
     """
+    if n < 0:
+        return []
     it = iter(iterable)
     result = list(islice(it, n))
     if not result:
@@ -209,6 +211,8 @@ def nsmallest(n, iterable):
 
     Equivalent to:  sorted(iterable)[:n]
     """
+    if n < 0:
+        return []
     if hasattr(iterable, '__len__') and n * 10 <= len(iterable):
         # For smaller values of n, the bisect method is faster than a minheap.
         # It is also memory efficient, consuming only n elements of space.