MutaFix run: toolz-011

ranker nvidia/NVIDIA-Nemotron-3-Nano-30B-A3B · patcher nvidia/nemotron-3-super-120b-a12b · via Nebius Token Factory

fixedoutcome
6swall time
2model calls
$0.0007API cost
Benchmark ground truth (hidden from the agent)
toolz/itertoolz.py:123 · operator NEGCOND · function toolz/itertoolz.py::merge_sorted
- if not (len(seqs) == 0):   (injected bug)+ if len(seqs) == 0:   (original)
retriever rank 1 of 20 · ranker position 1 · patched the right function yes · exact restore no

Trace

reproduce
+0.43s
1 failing test(s) · 1 failed, 185 passed, 1 skipped, 1 deselected · 0.43s
failing tests and errors
toolz/tests/test_itertoolz.py::test_merge_sorted
toolz/tests/test_itertoolz.py::test_merge_sorted
E   assert [] == [1, 1, 2, 2, 3, 3]
E     
E     Right contains 6 more items, first extra item: 1
E     Use -v to get more diff
trace
+0.81s
re-ran 1 test file(s) with the trace plugin: 1 failing and 50 passing tests, 1 library functions ran in a failing test · 0.35s
toolz/tests/test_itertoolz.py
retrieve
+0.81s
161 functions indexed, 9 reachable from toolz/tests/test_itertoolz.py::test_merge_sorted in the static call graph. Kept 20 candidates, ranked by spectrum score (Ochiai), call graph and BM25 break ties.
candidates in retriever order
  1. toolz/itertoolz.py::merge_sorted call depth 1 · Ochiai 1.00 (failing 1, passing 0)
  2. toolz/itertoolz.py::join call depth 1 · Ochiai 0.00 (failing 0, passing 7)
  3. toolz/functoolz.py::identity call depth 1 · Ochiai 0.00 (failing 0, passing 0)
  4. toolz/itertoolz.py::_merge_sorted_binary_key call depth 2 · Ochiai 0.00 (failing 0, passing 0)
  5. toolz/itertoolz.py::get call depth 2 · Ochiai 0.00 (failing 0, passing 1)
  6. toolz/itertoolz.py::_merge_sorted_binary call depth 2 · Ochiai 0.00 (failing 0, passing 0)
  7. toolz/itertoolz.py::groupby call depth 2 · Ochiai 0.00 (failing 0, passing 9)
  8. toolz/itertoolz.py::getter call depth 2 · Ochiai 0.00 (failing 0, passing 6)
  9. toolz/itertoolz.py::_get call depth 3 · Ochiai 0.00 (failing 0, passing 2)
  10. toolz/itertoolz.py::diff call depth - · Ochiai 0.00 (failing 0, passing 1)
  11. toolz/itertoolz.py::pluck call depth - · Ochiai 0.00 (failing 0, passing 1)
  12. toolz/dicttoolz.py::merge_with call depth - · Ochiai 0.00 (failing 0, passing 0)
  13. toolz/dicttoolz.py::get_in call depth - · Ochiai 0.00 (failing 0, passing 0)
  14. toolz/curried/exceptions.py::merge call depth - · Ochiai 0.00 (failing 0, passing 0)
  15. toolz/curried/exceptions.py::merge_with call depth - · Ochiai 0.00 (failing 0, passing 0)
  16. toolz/itertoolz.py::partition_all call depth - · Ochiai 0.00 (failing 0, passing 1)
  17. toolz/functoolz.py::_check_sigspec call depth - · Ochiai 0.00 (failing 0, passing 0)
  18. toolz/itertoolz.py::topk call depth - · Ochiai 0.00 (failing 0, passing 2)
  19. toolz/functoolz.py::compose call depth - · Ochiai 0.00 (failing 0, passing 0)
  20. toolz/itertoolz.py::concat call depth - · Ochiai 0.00 (failing 0, passing 5)
rank
+0.81s
spectrum order kept (no model call)
  1. toolz/itertoolz.py::merge_sorted
  2. toolz/itertoolz.py::join
  3. toolz/functoolz.py::identity
  4. toolz/itertoolz.py::_merge_sorted_binary_key
  5. toolz/itertoolz.py::get
read
+2.36s
turn 1 · NVIDIA-Nemotron-3-Nano-30B-A3B · 5113 in / 87 out · 1.54s · $0.00033

read toolz/itertoolz.py::merge_sorted

The failing test is merge_sorted, and the source shows the implementation of merge_sorted function. The bug appears to be in the condition `if not (len(seqs) == 0)` which should be `if not seqs` to correctly check for empty input. This causes incorrect handling of empty sequences.

patch
+5.65s
turn 2 · NVIDIA-Nemotron-3-Nano-30B-A3B · 5657 in / 193 out · 2.64s · $0.00039

The condition `if not (len(seqs) == 0)` is incorrect because it returns False when seqs is empty (since len(seqs) == 0 is True, so not True is False), but it should return True when seqs is empty. The correct way to check for empty *args is `if not seqs` which directly evaluates the truthiness of the tuple. This bug causes the function to return an empty iterator when called with no arguments, but the test expects it to return an empty list when called with no arguments (as seen in the test case `assert list(merge_sorted()) == []`). The patch fixes the condition to properly handle empty input.

--- a/toolz/itertoolz.py+++ b/toolz/itertoolz.py@@ -121,5 +121,5 @@     [2, 1, 3, 3]     """-    if not (len(seqs) == 0):+    if not seqs:         return iter([])     elif len(seqs) == 1:

tests: all tests pass 186 passed, 1 skipped, 1 deselected

Final patch

--- a/toolz/itertoolz.py+++ b/toolz/itertoolz.py@@ -121,5 +121,5 @@     [2, 1, 3, 3]     """-    if not (len(seqs) == 0):+    if not seqs:         return iter([])     elif len(seqs) == 1: