MutaFix run: sortedcontainers-009

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

fixedoutcome
20swall time
3model calls
$0.0028API cost
Benchmark ground truth (hidden from the agent)
src/sortedcontainers/sortedlist.py:1825 · operator NEGCOND · function src/sortedcontainers/sortedlist.py::SortedKeyList.__contains__
- if not (pos == len(_maxes)):   (injected bug)+ if pos == len(_maxes):   (original)
retriever rank 1 of 20 · ranker position 1 · patched the right function yes · exact restore yes

Trace

reproduce
+1.86s
5 failing test(s) · 5 failed, 294 passed · 1.86s
failing tests and errors
tests/test_coverage_sortedkeylist_modulo.py::test_key
tests/test_coverage_sortedkeylist_modulo.py::test_contains
tests/test_coverage_sortedkeylist_negate.py::test_key
tests/test_coverage_sortedkeylist_negate.py::test_contains
tests/test_stress_sortedkeylist.py::test_stress
tests/test_coverage_sortedkeylist_modulo.py::test_key
E   assert False
E    +  where False = all(<generator object test_key.<locals>.<genexpr> at 0x000001F395AD3370>)
tests/test_coverage_sortedkeylist_modulo.py::test_contains
E   assert 0 in SortedKeyList([9999, 9998, 9997, 9996, 9995, 9994, 9993, 9992, 9991, 9990, 9989, 9988, 9987, 9986, 9985, 9984, 9983, 9...20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0], key=<function negate at 0x000001F395AA8400>)
trace
+2.58s
re-ran 3 test file(s) with the trace plugin: 5 failing and 120 passing tests, 25 library functions ran in a failing test · 0.69s
tests/test_coverage_sortedkeylist_modulo.py, tests/test_coverage_sortedkeylist_negate.py, tests/test_stress_sortedkeylist.py
retrieve
+2.58s
129 functions indexed, 39 reachable from tests/test_coverage_sortedkeylist_modulo.py::test_key in the static call graph. Kept 20 candidates, ranked by spectrum score (Ochiai), call graph and BM25 break ties.
candidates in retriever order
  1. src/sortedcontainers/sortedlist.py::SortedKeyList.__contains__ call depth 1 · Ochiai 1.00 (failing 5, passing 0)
  2. src/sortedcontainers/sortedlist.py::SortedKeyList.__repr__ call depth 1 · Ochiai 0.51 (failing 3, passing 4)
  3. src/sortedcontainers/sortedlist.py::SortedList.__iter__ call depth 3 · Ochiai 0.34 (failing 5, passing 39)
  4. src/sortedcontainers/sortedlist.py::identity call depth - · Ochiai 0.32 (failing 1, passing 1)
  5. src/sortedcontainers/sortedlist.py::SortedList.__make_cmp.<locals>.comparer call depth - · Ochiai 0.27 (failing 3, passing 21)
  6. src/sortedcontainers/sortedlist.py::SortedKeyList.bisect_left call depth 2 · Ochiai 0.26 (failing 1, passing 2)
  7. src/sortedcontainers/sortedlist.py::SortedList.__reversed__ call depth 3 · Ochiai 0.26 (failing 1, passing 2)
  8. src/sortedcontainers/sortedlist.py::SortedKeyList.count call depth - · Ochiai 0.26 (failing 1, passing 2)
  9. src/sortedcontainers/sortedlist.py::SortedList.__len__ call depth 3 · Ochiai 0.23 (failing 3, passing 31)
  10. src/sortedcontainers/sortedlist.py::SortedKeyList.bisect_key_left call depth - · Ochiai 0.22 (failing 1, passing 3)
  11. src/sortedcontainers/sortedlist.py::SortedKeyList._check call depth 1 · Ochiai 0.21 (failing 3, passing 36)
  12. src/sortedcontainers/sortedlist.py::SortedKeyList.update call depth - · Ochiai 0.21 (failing 5, passing 106)
  13. src/sortedcontainers/sortedlist.py::SortedKeyList.__new__ call depth 1 · Ochiai 0.20 (failing 5, passing 117)
  14. src/sortedcontainers/sortedlist.py::SortedKeyList.__init__ call depth 1 · Ochiai 0.20 (failing 5, passing 117)
  15. src/sortedcontainers/sortedlist.py::SortedKeyList.__mul__ call depth 1 · Ochiai 0.20 (failing 1, passing 4)
  16. src/sortedcontainers/sortedlist.py::SortedKeyList.remove call depth - · Ochiai 0.12 (failing 1, passing 12)
  17. src/sortedcontainers/sortedlist.py::SortedKeyList._delete call depth - · Ochiai 0.12 (failing 1, passing 14)
  18. src/sortedcontainers/sortedlist.py::SortedList._loc call depth 3 · Ochiai 0.11 (failing 1, passing 15)
  19. src/sortedcontainers/sortedlist.py::SortedList.__getitem__ call depth 3 · Ochiai 0.11 (failing 1, passing 16)
  20. src/sortedcontainers/sortedlist.py::SortedKeyList.add call depth - · Ochiai 0.10 (failing 1, passing 17)
rank
+2.58s
spectrum order kept (no model call)
  1. src/sortedcontainers/sortedlist.py::SortedKeyList.__contains__
  2. src/sortedcontainers/sortedlist.py::SortedKeyList.__repr__
  3. src/sortedcontainers/sortedlist.py::SortedList.__iter__
  4. src/sortedcontainers/sortedlist.py::identity
  5. src/sortedcontainers/sortedlist.py::SortedList.__make_cmp.<locals>.comparer
read
+3.51s
turn 1 · NVIDIA-Nemotron-3-Nano-30B-A3B · 2838 in / 116 out · 0.93s · $0.00020

read src/sortedcontainers/sortedlist.py::SortedKeyList.__contains__

The failing tests involve membership checks (`in`) on a SortedKeyList with a modulo key function. The __contains__ method is the only one directly responsible for membership testing, and it is the only candidate that appears in all 5 failing tests. The current implementation has a logic error in the loop that checks elements in the bucket, specifically in how it handles the case where the key is found but the value does not match, leading to incorrect False results.

patch
+6.46s
turn 2 · NVIDIA-Nemotron-3-Nano-30B-A3B · 3627 in / 385 out · 2.57s · $0.00031

The bug is in the __contains__ method where after moving to the next bucket (pos += 1), the code does not update the local variable `len_sublist` to reflect the length of the new bucket's key list. This causes the loop to use the old `len_sublist` value, potentially leading to incorrect index checks and early termination. However, the immediate fix requires ensuring that after updating `pos`, we also update `len_sublist` and `idx` correctly. The actual issue is that the condition `if idx == len_sublist` uses the old `len_sublist` from the previous bucket. The fix is to update `len_sublist` after incrementing `pos` to the new bucket's key list length.

--- a/src/sortedcontainers/sortedlist.py+++ b/src/sortedcontainers/sortedlist.py@@ -1844,4 +1844,5 @@                 if pos == len_keys:                     return False+                _keys[pos]  # Access to update _keys reference                 len_sublist = len(_keys[pos])                 idx = 0

tests: 5 failing (target tests) 5 failed

tests/test_coverage_sortedkeylist_modulo.py::test_key
tests/test_coverage_sortedkeylist_modulo.py::test_contains
tests/test_coverage_sortedkeylist_negate.py::test_key
tests/test_coverage_sortedkeylist_negate.py::test_contains
tests/test_stress_sortedkeylist.py::test_stress
patch
+19.71s
turn 3 · nemotron-3-super-120b-a12b · 4357 in / 1071 out · 9.69s · $0.00227

The condition for returning False when the key is greater than all sublist maximums was reversed. The original code returned False when a valid sublist was found (pos != len(_maxes)), causing it to incorrectly reject present elements. The fix correctly returns False only when pos equals len(_maxes), meaning the key exceeds all maximums and cannot be present.

--- a/src/sortedcontainers/sortedlist.py+++ b/src/sortedcontainers/sortedlist.py@@ -1823,5 +1823,5 @@         pos = bisect_left(_maxes, key) -        if not (pos == len(_maxes)):+        if pos == len(_maxes):             return False

tests: all tests pass 299 passed

model reasoning (excerpt)
We need to re-examine the __contains__ method. The problem might be earlier: the initial check using `_maxes`.

Look at lines 1825-1826:

        if not (pos == len(_maxes)):
            return False

This condition seems wrong. Let's understand what `bisect_left(_maxes, key)` returns. `_maxes` is a list of the maximum key in each sublist (or maybe the last key? Actually in SortedList, `_maxes` stores the last element of each sublist? For SortedKeyList, it should store the maximum key in each sublist? We need to recall the structure.

In sortedcontainers, SortedList uses `_lists` (list of sublists) and `_maxes` (list of the maximum value in each sublist). For SortedKeyList, it should be similar but using keys.

The idea: to find which sublist might contain the key, we do `bisect_left(_maxes, key)`. This returns the index of the first sublist whose max key is >= key. Then we check that sublist.

But note: if the key is greater than all maxes, then `pos` will be `len(_maxes)`. In that case, the key is not present because it's larger than any key in the list. So we should return False when `pos == len(_maxes)`. However, the code says:

        if not (pos == len(_maxes)):
            return False

That means: if pos is NOT equal to len(_maxes), return False. That's backwards! It should be: if pos == len(_maxes): return False.

Let's verify: Suppose key is less than or equal to some max. Then pos will be the index of the first sublist with max >= key, which is a valid index (0 <=

Final patch

--- a/src/sortedcontainers/sortedlist.py+++ b/src/sortedcontainers/sortedlist.py@@ -1823,5 +1823,5 @@         pos = bisect_left(_maxes, key) -        if not (pos == len(_maxes)):+        if pos == len(_maxes):             return False