MutaFix run: toolz-008

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

fixedoutcome
22swall time
3model calls
$0.0042API cost
Benchmark ground truth (hidden from the agent)
toolz/functoolz.py:74 · operator NEGCOND · function toolz/functoolz.py::thread_first.<locals>.evalform_front
- if not (isinstance(form, tuple)):   (injected bug)+ if isinstance(form, tuple):   (original)
retriever rank 1 of 20 · ranker position 1 · patched the right function yes · exact restore yes

Trace

reproduce
+0.46s
1 failing test(s) · 1 failed, 185 passed, 1 skipped, 1 deselected · 0.46s
failing tests and errors
toolz/tests/test_functoolz.py::test_thread_first
toolz/tests/test_functoolz.py::test_thread_first
E   TypeError: unsupported operand type(s) for *: 'int' and 'NoneType'
trace
+0.86s
re-ran 1 test file(s) with the trace plugin: 1 failing and 38 passing tests, 2 library functions ran in a failing test · 0.36s
toolz/tests/test_functoolz.py
retrieve
+0.86s
161 functions indexed, 4 reachable from toolz/tests/test_functoolz.py::test_thread_first 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/functoolz.py::thread_first call depth 1 · Ochiai 1.00 (failing 1, passing 0)
  2. toolz/functoolz.py::thread_first.<locals>.evalform_front call depth 1 · Ochiai 1.00 (failing 1, passing 0)
  3. toolz/functoolz.py::curry.func call depth 2 · Ochiai 0.00 (failing 0, passing 17)
  4. toolz/functoolz.py::curry.args call depth 2 · Ochiai 0.00 (failing 0, passing 16)
  5. toolz/functoolz.py::thread_last call depth - · Ochiai 0.00 (failing 0, passing 1)
  6. toolz/functoolz.py::apply call depth - · Ochiai 0.00 (failing 0, passing 1)
  7. toolz/functoolz.py::pipe call depth - · Ochiai 0.00 (failing 0, passing 1)
  8. toolz/functoolz.py::do call depth - · Ochiai 0.00 (failing 0, passing 1)
  9. toolz/functoolz.py::Compose._combined_annotations call depth - · Ochiai 0.00 (failing 0, passing 2)
  10. toolz/functoolz.py::memoize call depth - · Ochiai 0.00 (failing 0, passing 9)
  11. toolz/functoolz.py::memoize.<locals>.memof call depth - · Ochiai 0.00 (failing 0, passing 8)
  12. toolz/itertoolz.py::iterate call depth - · Ochiai 0.00 (failing 0, passing 0)
  13. toolz/_signatures.py::signature_or_spec call depth - · Ochiai 0.00 (failing 0, passing 12)
  14. toolz/itertoolz.py::isiterable call depth - · Ochiai 0.00 (failing 0, passing 0)
  15. toolz/functoolz.py::Compose.__name__ call depth - · Ochiai 0.00 (failing 0, passing 2)
  16. toolz/functoolz.py::curry.__call__ call depth - · Ochiai 0.00 (failing 0, passing 22)
  17. toolz/itertoolz.py::tail call depth - · Ochiai 0.00 (failing 0, passing 0)
  18. toolz/dicttoolz.py::_get_factory call depth - · Ochiai 0.00 (failing 0, passing 0)
  19. toolz/functoolz.py::_check_sigspec call depth - · Ochiai 0.00 (failing 0, passing 0)
  20. toolz/functoolz.py::is_valid_args call depth - · Ochiai 0.00 (failing 0, passing 12)
rank
+0.86s
spectrum order kept (no model call)
  1. toolz/functoolz.py::thread_first
  2. toolz/functoolz.py::thread_first.<locals>.evalform_front
  3. toolz/functoolz.py::curry.func
  4. toolz/functoolz.py::curry.args
  5. toolz/functoolz.py::thread_last
read
+2.82s
turn 1 · NVIDIA-Nemotron-3-Nano-30B-A3B · 2242 in / 148 out · 1.96s · $0.00017

read toolz/functoolz.py::thread_first

The test failure shows a TypeError involving multiplication with None, which suggests that a function is returning None when it should return a numeric value. Looking at the implementation of thread_first, the issue likely lies in the evalform_front helper function, particularly in how it handles tuple forms. The current code incorrectly unpacks tuple forms by using form[1:] for args, but when the tuple represents a function with multiple arguments, the first element after the function is being treated as part of the args rather than as an additional argument to be prepended to val. This causes a None to be passed where a number is expected.

patch
+6.25s
turn 2 · NVIDIA-Nemotron-3-Nano-30B-A3B · 2866 in / 238 out · 3.1s · $0.00023

The bug is in the evalform_front function. When a form is a tuple, the current code incorrectly constructs args by prepending val to the tuple's arguments (args = (val,) + args). This causes the function to be called with the wrong argument structure. Instead, the function should be called with val as the first argument and the tuple's arguments as additional arguments, which is achieved by func(val, *args). This matches the expected behavior described in the docstring where thread_first(1, (add, 4), (pow, 2)) expands to pow(add(1, 4), 2).

--- a/toolz/functoolz.py+++ b/toolz/functoolz.py@@ -74,6 +74,5 @@         if not (isinstance(form, tuple)):             func, args = form[0], form[1:]-            args = (val,) + args-            return func(*args)+            return func(val, *args)     return reduce(evalform_front, forms, val)

tests: 1 failing (target tests) 1 failed

toolz/tests/test_functoolz.py::test_thread_first
patch
+22.4s
turn 3 · nemotron-3-super-120b-a12b · 3192 in / 3125 out · 15.52s · $0.00377

The condition for handling tuple forms was inverted. The original code skipped tuple forms (because of the 'not') and fell through without returning a value, causing None to be passed to the next form. By removing the 'not', tuple forms are properly handled: the function is called with the accumulated value as the first argument and the tuple's arguments as additional arguments.

--- a/toolz/functoolz.py+++ b/toolz/functoolz.py@@ -72,5 +72,5 @@         if callable(form):             return form(val)-        if not (isinstance(form, tuple)):+        if isinstance(form, tuple):             func, args = form[0], form[1:]             args = (val,) + args

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

model reasoning (excerpt)
We need to reexamine the error: "unsupported operand type(s) for *: 'int' and 'NoneType'"
This indicates we are trying to multiply an int by None. In the test case:
assert thread_first(2, (add, 5), double) == 14
Let's break down what should happen:
Start with val=2
First form: (add, 5) -> should compute add(2,5) = 7
Second form: double -> should compute double(7) = 14

But our current implementation (after the failed patch) does:
For form=(add,5):
  Since it's a tuple, we go into the if block? Wait, note: the condition is "if not (isinstance(form, tuple)):" meaning if it's NOT a tuple then we do that block. But (add,5) IS a tuple, so we skip that block and fall through? Actually there's no else and no return for the tuple case! That means for tuple forms, the function evalform_front doesn't return anything (i.e., returns None). Then we try to apply the next form (double) to None, and double(None) would be 2*None? No, double is defined as lambda x: 2*x, so 2 * None -> TypeError.

So the real bug is that the tuple case is not handled at all. We need to handle the tuple case.

Looking at the original code before our patch:
        if callable(form):
            return form(val)
        if not (isinstance(form, tuple)):
            func, args = form[0], form[1:]
            args = (val,) + args
            return func(*args)

Wait, the condition is "if not (isinstance(form, tuple))" meaning if form is NOT a tuple, then we do the unpacking. But that seems backwards: we want to han

Final patch

--- a/toolz/functoolz.py+++ b/toolz/functoolz.py@@ -72,5 +72,5 @@         if callable(form):             return form(val)-        if not (isinstance(form, tuple)):+        if isinstance(form, tuple):             func, args = form[0], form[1:]             args = (val,) + args