MutaFix run: sortedcontainers-002

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

fixedoutcome
9swall time
2model calls
$0.0006API cost
Benchmark ground truth (hidden from the agent)
src/sortedcontainers/sortedlist.py:2283 · operator CMP · function src/sortedcontainers/sortedlist.py::SortedKeyList.count
- if idx != len_sublist:   (injected bug)+ if idx == len_sublist:   (original)
retriever rank 1 of 20 · ranker position 1 · patched the right function yes · exact restore yes

Trace

reproduce
+1.86s
3 failing test(s) · 3 failed, 296 passed · 1.86s
failing tests and errors
tests/test_coverage_sortedkeylist_modulo.py::test_count
tests/test_coverage_sortedkeylist_negate.py::test_count
tests/test_stress_sortedkeylist.py::test_stress
tests/test_coverage_sortedkeylist_modulo.py::test_count
E   IndexError: list index out of range
tests/test_coverage_sortedkeylist_negate.py::test_count
E   IndexError: list index out of range
trace
+3.08s
re-ran 3 test file(s) with the trace plugin: 3 failing and 122 passing tests, 31 library functions ran in a failing test · 1.21s
tests/test_coverage_sortedkeylist_modulo.py, tests/test_coverage_sortedkeylist_negate.py, tests/test_stress_sortedkeylist.py
retrieve
+3.08s
129 functions indexed, 50 reachable from tests/test_coverage_sortedkeylist_modulo.py::test_count 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.count call depth 1 · Ochiai 1.00 (failing 3, passing 0)
  2. src/sortedcontainers/sortedlist.py::SortedKeyList.__repr__ call depth 1 · Ochiai 0.47 (failing 2, passing 4)
  3. src/sortedcontainers/sortedlist.py::identity call depth - · Ochiai 0.41 (failing 1, passing 1)
  4. src/sortedcontainers/sortedlist.py::SortedKeyList.add call depth 1 · Ochiai 0.41 (failing 3, passing 15)
  5. src/sortedcontainers/sortedlist.py::SortedKeyList._expand call depth 2 · Ochiai 0.35 (failing 3, passing 22)
  6. src/sortedcontainers/sortedlist.py::SortedKeyList.bisect_left call depth 2 · Ochiai 0.33 (failing 1, passing 2)
  7. src/sortedcontainers/sortedlist.py::SortedList.__imul__ call depth 3 · Ochiai 0.33 (failing 1, passing 2)
  8. src/sortedcontainers/sortedlist.py::SortedList.__reversed__ call depth 3 · Ochiai 0.33 (failing 1, passing 2)
  9. src/sortedcontainers/sortedlist.py::SortedKeyList.bisect_key_left call depth - · Ochiai 0.29 (failing 1, passing 3)
  10. src/sortedcontainers/sortedlist.py::SortedKeyList._check call depth 1 · Ochiai 0.27 (failing 3, passing 38)
  11. src/sortedcontainers/sortedlist.py::SortedKeyList.__mul__ call depth 1 · Ochiai 0.26 (failing 1, passing 4)
  12. src/sortedcontainers/sortedlist.py::SortedKeyList.__contains__ call depth 1 · Ochiai 0.26 (failing 1, passing 4)
  13. src/sortedcontainers/sortedlist.py::SortedKeyList.bisect_right call depth 2 · Ochiai 0.26 (failing 1, passing 4)
  14. src/sortedcontainers/sortedlist.py::SortedKeyList.discard call depth - · Ochiai 0.26 (failing 1, passing 4)
  15. src/sortedcontainers/sortedlist.py::SortedList.__delitem__ call depth 3 · Ochiai 0.22 (failing 1, passing 6)
  16. src/sortedcontainers/sortedlist.py::SortedList.pop call depth - · Ochiai 0.22 (failing 1, passing 6)
  17. src/sortedcontainers/sortedlist.py::SortedKeyList.bisect_key_right call depth - · Ochiai 0.22 (failing 1, passing 6)
  18. src/sortedcontainers/sortedlist.py::SortedList.__len__ call depth 3 · Ochiai 0.20 (failing 2, passing 31)
  19. src/sortedcontainers/sortedlist.py::SortedKeyList.clear call depth - · Ochiai 0.18 (failing 3, passing 87)
  20. src/sortedcontainers/sortedlist.py::SortedList.__iter__ call depth 3 · Ochiai 0.18 (failing 2, passing 41)
rank
+3.08s
spectrum order kept (no model call)
  1. src/sortedcontainers/sortedlist.py::SortedKeyList.count
  2. src/sortedcontainers/sortedlist.py::SortedKeyList.__repr__
  3. src/sortedcontainers/sortedlist.py::identity
  4. src/sortedcontainers/sortedlist.py::SortedKeyList.add
  5. src/sortedcontainers/sortedlist.py::SortedKeyList._expand
read
+4.48s
turn 1 · NVIDIA-Nemotron-3-Nano-30B-A3B · 3704 in / 81 out · 1.4s · $0.00024

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

The failing tests report an IndexError in count() and incorrect count results. Candidate 1 is the only function directly related to counting elements in a SortedKeyList, and its logic involves bisect operations and traversing sublists that could cause index errors if bounds are miscalculated.

patch
+9.44s
turn 2 · NVIDIA-Nemotron-3-Nano-30B-A3B · 4428 in / 349 out · 1.8s · $0.00035

The bug is in the condition that checks whether to continue traversing sublists. The original code uses `if idx != len_sublist:` to decide whether to move to the next sublist, but this causes an off-by-one error when `idx` equals `len_sublist`, leading to an IndexError when accessing `_keys[pos][idx]` or `_lists[pos][idx]`. The condition should be `if idx == len_sublist:` to correctly trigger the move to the next sublist when the current one has been fully processed. This matches the fault localization model for candidate 1 and resolves the IndexError in the failing tests.

--- a/src/sortedcontainers/sortedlist.py+++ b/src/sortedcontainers/sortedlist.py@@ -2281,5 +2281,5 @@                 total += 1             idx += 1-            if idx != len_sublist:+            if idx == len_sublist:                 pos += 1                 if pos == len_keys:

tests: all tests pass 299 passed

Final patch

--- a/src/sortedcontainers/sortedlist.py+++ b/src/sortedcontainers/sortedlist.py@@ -2281,5 +2281,5 @@                 total += 1             idx += 1-            if idx != len_sublist:+            if idx == len_sublist:                 pos += 1                 if pos == len_keys: