MutaFix run: sortedcontainers-004

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

fixedoutcome
18swall time
3model calls
$0.0030API cost
Benchmark ground truth (hidden from the agent)
src/sortedcontainers/sortedset.py:395 · operator NEGCOND · function src/sortedcontainers/sortedset.py::SortedSet.discard
- if not (value in _set):   (injected bug)+ if value in _set:   (original)
retriever rank 1 of 20 · ranker position 1 · patched the right function yes · exact restore yes

Trace

reproduce
+2.49s
3 failing test(s) · 3 failed, 296 passed · 2.49s
failing tests and errors
tests/test_coverage_sortedset.py::test_difference_update
tests/test_coverage_sortedset.py::test_isub
tests/test_coverage_sortedset.py::test_discard
tests/test_coverage_sortedset.py::test_difference_update
E   assert False
E    +  where False = all(<generator object test_difference_update.<locals>.<genexpr> at 0x0000021F2E697E60>)
tests/test_coverage_sortedset.py::test_isub
E   assert False
E    +  where False = all(<generator object test_isub.<locals>.<genexpr> at 0x0000021F31550BA0>)
trace
+2.9s
re-ran 1 test file(s) with the trace plugin: 3 failing and 47 passing tests, 11 library functions ran in a failing test · 0.39s
tests/test_coverage_sortedset.py
retrieve
+2.9s
129 functions indexed, 74 reachable from tests/test_coverage_sortedset.py::test_difference_update 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/sortedset.py::SortedSet.discard call depth - · Ochiai 1.00 (failing 3, passing 0)
  2. src/sortedcontainers/sortedset.py::SortedSet.difference_update call depth 1 · Ochiai 0.82 (failing 2, passing 0)
  3. src/sortedcontainers/sortedlist.py::SortedList.update call depth 2 · Ochiai 0.26 (failing 3, passing 40)
  4. src/sortedcontainers/sortedlist.py::SortedList.clear call depth 2 · Ochiai 0.26 (failing 3, passing 40)
  5. src/sortedcontainers/sortedlist.py::SortedList.__init__ call depth 2 · Ochiai 0.26 (failing 3, passing 40)
  6. src/sortedcontainers/sortedlist.py::SortedList._reset call depth 1 · Ochiai 0.25 (failing 3, passing 45)
  7. src/sortedcontainers/sortedset.py::SortedSet.__init__ call depth 1 · Ochiai 0.24 (failing 3, passing 47)
  8. src/sortedcontainers/sortedset.py::SortedSet.update call depth 2 · Ochiai 0.24 (failing 3, passing 47)
  9. src/sortedcontainers/sortedlist.py::SortedList.__new__ call depth 2 · Ochiai 0.24 (failing 3, passing 47)
  10. src/sortedcontainers/sortedset.py::SortedSet.__getitem__ call depth 1 · Ochiai 0.24 (failing 2, passing 21)
  11. src/sortedcontainers/sortedlist.py::SortedList.__getitem__ call depth 2 · Ochiai 0.23 (failing 2, passing 23)
  12. src/sortedcontainers/sortedset.py::SortedSet.__delitem__ call depth 1 · Ochiai 0.00 (failing 0, passing 3)
  13. src/sortedcontainers/sortedset.py::SortedSet.__contains__ call depth 1 · Ochiai 0.00 (failing 0, passing 1)
  14. src/sortedcontainers/sortedset.py::SortedSet.__reduce__ call depth 1 · Ochiai 0.00 (failing 0, passing 1)
  15. src/sortedcontainers/sortedset.py::SortedSet.__iter__ call depth 1 · Ochiai 0.00 (failing 0, passing 14)
  16. src/sortedcontainers/sortedset.py::SortedSet.__reversed__ call depth 1 · Ochiai 0.00 (failing 0, passing 1)
  17. src/sortedcontainers/sortedset.py::SortedSet.__len__ call depth 1 · Ochiai 0.00 (failing 0, passing 7)
  18. src/sortedcontainers/sortedset.py::SortedSet.__repr__ call depth 1 · Ochiai 0.00 (failing 0, passing 2)
  19. src/sortedcontainers/sortedlist.py::SortedKeyList.update call depth 2 · Ochiai 0.00 (failing 0, passing 7)
  20. src/sortedcontainers/sorteddict.py::SortedDict.update call depth 2 · Ochiai 0.00 (failing 0, passing 0)
rank
+2.9s
spectrum order kept (no model call)
  1. src/sortedcontainers/sortedset.py::SortedSet.discard
  2. src/sortedcontainers/sortedset.py::SortedSet.difference_update
  3. src/sortedcontainers/sortedlist.py::SortedList.update
  4. src/sortedcontainers/sortedlist.py::SortedList.clear
  5. src/sortedcontainers/sortedlist.py::SortedList.__init__
read
+4.31s
turn 1 · NVIDIA-Nemotron-3-Nano-30B-A3B · 3016 in / 84 out · 1.41s · $0.00020

read src/sortedcontainers/sortedset.py::SortedSet.difference_update

The failing tests involve difference_update, isub (which uses difference_update), and discard. The error messages indicate issues with generator expressions and KeyError, suggesting a problem in the difference_update implementation. Candidate 2 is the SortedSet.difference_update method, which is directly implicated in the failing tests.

patch
+5.86s
turn 2 · NVIDIA-Nemotron-3-Nano-30B-A3B · 3555 in / 190 out · 1.25s · $0.00026

The test test_discard expects a KeyError when removing a non-existent value, but the current implementation silently ignores missing values via _discard. The failing tests show that missing values cause assertion failures. The patch ensures that when discarding a value, it is actually removed from both _set and _list if present, matching set.discard behavior and preserving the expected KeyError for missing values.

--- a/src/sortedcontainers/sortedset.py+++ b/src/sortedcontainers/sortedset.py@@ -500,4 +500,7 @@             for value in values:                 _discard(value)+                if value in _set:+                    _set.remove(value)+                    _list.remove(value)         return self

tests: 1 failing (target tests) 1 failed, 2 passed

tests/test_coverage_sortedset.py::test_discard
patch
+18.01s
turn 3 · nemotron-3-super-120b-a12b · 3822 in / 1499 out · 9.45s · $0.00250

The discard method had a logic error: it attempted to remove values only when they were NOT present, causing KeyError for missing values. The condition should be inverted to only remove when the value is present, matching the docstring and set semantics.

--- a/src/sortedcontainers/sortedset.py+++ b/src/sortedcontainers/sortedset.py@@ -393,5 +393,5 @@         """         _set = self._set-        if not (value in _set):+        if value in _set:             _set.remove(value)             self._list.remove(value)

tests: all tests pass 299 passed

model reasoning (excerpt)
We need to understand what's happening. The test_discard is expecting a KeyError? Actually looking back at the original test snippet we didn't see test_discard content. Let's examine the test file to see what test_discard does.

But we can infer: The test_discard likely checks that discard raises KeyError when trying to discard a non-existent element? However, the standard set.discard does NOT raise KeyError; it does nothing. But SortedSet might be designed to mimic set? Actually the docstring of discard says: "If `value` is not a member, do nothing." So discard should not raise KeyError. Yet the test expects a KeyError? That seems odd.

Maybe the test is checking that discard raises KeyError for some other reason? Or maybe the test is actually testing __delitem__? Let's look at the test file.

We need to read the test file to understand. We'll do a read action on the test file (though not listed as candidate, we can still read it? The system allows read on any candidate? The instructions say we can only read candidate functions, but we can also read test? Not sure. But we can ask to read the test file if needed. However, we can also look at the error: KeyError: 1000. That suggests that when trying to discard 1000, a KeyError is raised. That means the discard method is raising KeyError when the value is not present. But the docstring says it should do nothing. So maybe the bug is that discard is incorrectly raising KeyError, and the test expects that? Wait, the test is named

Final patch

--- a/src/sortedcontainers/sortedset.py+++ b/src/sortedcontainers/sortedset.py@@ -393,5 +393,5 @@         """         _set = self._set-        if not (value in _set):+        if value in _set:             _set.remove(value)             self._list.remove(value)