MutaFix run: boltons-009

tests/test_ioutils.py::TestSpooledBytesIO::test_auto_rollover
tests/test_ioutils.py::TestSpooledBytesIO::test_buf_property
tests/test_ioutils.py::TestSpooledBytesIO::test_buffer_write_rollover_uses_byte_count
tests/test_ioutils.py::TestSpooledBytesIO::test_closed_file_method_valueerrors
tests/test_ioutils.py::TestSpooledBytesIO::test_compare_different_instances
tests/test_ioutils.py::TestSpooledBytesIO::test_compare_err
tests/test_ioutils.py::TestSpooledBytesIO::test_compare_not_equal_instances
tests/test_ioutils.py::TestSpooledBytesIO::test_compare_two_equal_instances
tests/test_ioutils.py::TestSpooledBytesIO::test_flush_after_rollover
tests/test_ioutils.py::TestSpooledBytesIO::test_getvalue_norollover
tests/test_ioutils.py::TestSpooledBytesIO::test_getvalue_rollover
tests/test_ioutils.py::TestSpooledBytesIO::test_invalid_type
tests/test_ioutils.py::TestSpooledBytesIO::test_io_error_negative_truncate
tests/test_ioutils.py::TestSpooledBytesIO::test_isatty
tests/test_ioutils.py::TestSpooledBytesIO::test_iter
tests/test_ioutils.py::TestSpooledBytesIO::test_len_no_rollover
tests/test_ioutils.py::TestSpooledBytesIO::test_len_rollover
tests/test_ioutils.py::TestSpooledBytesIO::test_next
tests/test_ioutils.py::TestSpooledBytesIO::test_pos_property
tests/test_ioutils.py::TestSpooledBytesIO::test_readline

E   ValueError: I/O operation on closed file.

E   ValueError: I/O operation on closed file.

1. boltons/ioutils.py::SpooledIOBase._checkClosed call depth 2 · Ochiai 1.00 (failing 74, passing 0)
2. boltons/ioutils.py::SpooledIOBase.closed call depth 2 · Ochiai 0.99 (failing 74, passing 2)
3. boltons/ioutils.py::SpooledIOBase.__init__ call depth - · Ochiai 0.94 (failing 74, passing 10)
4. boltons/ioutils.py::SpooledStringIO.__init__ call depth - · Ochiai 0.70 (failing 41, passing 5)
5. boltons/ioutils.py::SpooledStringIO.buffer call depth 2 · Ochiai 0.69 (failing 40, passing 5)
6. boltons/ioutils.py::SpooledBytesIO.buffer call depth 2 · Ochiai 0.65 (failing 36, passing 5)
7. boltons/ioutils.py::SpooledStringIO.write call depth 1 · Ochiai 0.64 (failing 30, passing 0)
8. boltons/ioutils.py::SpooledBytesIO.write call depth 1 · Ochiai 0.57 (failing 24, passing 0)
9. boltons/ioutils.py::SpooledIOBase.close call depth 3 · Ochiai 0.40 (failing 18, passing 10)
10. boltons/ioutils.py::SpooledIOBase.__del__ call depth - · Ochiai 0.35 (failing 15, passing 10)
11. boltons/ioutils.py::SpooledIOBase.__enter__ call depth - · Ochiai 0.31 (failing 7, passing 0)
12. boltons/ioutils.py::SpooledIOBase.pos call depth 3 · Ochiai 0.23 (failing 4, passing 0)
13. boltons/ioutils.py::SpooledIOBase.isatty call depth - · Ochiai 0.23 (failing 4, passing 0)
14. boltons/ioutils.py::SpooledBytesIO.tell call depth 2 · Ochiai 0.20 (failing 3, passing 0)
15. boltons/ioutils.py::SpooledIOBase.getvalue call depth 3 · Ochiai 0.20 (failing 3, passing 0)
16. boltons/ioutils.py::SpooledIOBase.buf call depth - · Ochiai 0.20 (failing 3, passing 0)
17. boltons/ioutils.py::SpooledStringIO.tell call depth 2 · Ochiai 0.16 (failing 2, passing 0)
18. boltons/ioutils.py::SpooledBytesIO.seek call depth 3 · Ochiai 0.16 (failing 2, passing 0)
19. boltons/ioutils.py::SpooledIOBase.writelines call depth - · Ochiai 0.16 (failing 2, passing 0)
20. boltons/ioutils.py::SpooledIOBase.flush call depth - · Ochiai 0.16 (failing 2, passing 0)

We have a recursion error because we added a check for `self.closed` which in turn accesses `self.buffer.closed` (since `closed` property returns `self.buffer.closed`). This causes infinite recursion.

 We need to avoid using `self.closed` in the buffer property because it depends on the buffer being available.

 Instead, we should check if the SpooledBytesIO instance is closed by looking at an internal flag. Let's look at the SpooledIOBase class to see how `closed` is implemented and if there's an internal flag.

 From the earlier read of candidate [2]:
   SpooledIOBase.closed (boltons/ioutils.py)
       154 |     @property
       155 |     def closed(self):
       156 |         return self.buffer.closed

 So indeed, `closed` depends on `buffer`. Therefore, we cannot use `self.closed` in the buffer property.

 We need to find another way to check if the SpooledBytesIO is closed. Let's look at the SpooledIOBase class for an internal flag.

 Since we don't have the full source, we can infer from the `__init__` and `close` methods.

 Let's read the SpooledIOBase class (candidate [1] and [9]) to see if there's a `_closed` attribute or similar.

 However, we are limited in reads. Let's try to read the SpooledIOBase class to see its attributes.

 But note: we have only 2 reads left. We must be cautious.

 Alternatively, we can look at the `close` method (candidate [9]) to see how it sets the closed state.

 Let's read candidate [9]: SpooledIOBase.close

 But wait, we are currently

We have a recursion error because our patch caused infinite recursion: checking `self.closed` in the buffer property, and `self.closed` likely accesses `self.buffer.closed` (from candidate 2), which then calls the buffer property again.

Let's look at candidate 2: SpooledIOBase.closed.

We need to see the closed property to understand the dependency.

But first, let's revert our patch and think differently.

The error is that we get "I/O operation on closed file" when we shouldn't. The _checkClosed method (candidate 1) is raising the error when the file is NOT closed? Wait, let's read candidate 1 again:

```
   76 |     def _checkClosed(self, msg=None):
   77 |         """Raise a ValueError if file is closed"""
   78 |         if not (self.closed):
   79 |             raise ValueError('I/O operation on closed file.'
   80 |                              if msg is None else msg)
```

This is clearly wrong: it raises an error when the file is NOT closed. The condition should be `if self.closed:` to raise when closed.

But note: the error message says "I/O operation on closed file", so we want to raise when the file is closed.

So the bug is in _checkClosed: it raises when the file is open, and does nothing when closed.

That would cause operations to be allowed on closed files? Actually, no: the test is getting an error on closed file, meaning that the error is being raised when the file is closed? Wait, the test error is:

```
E   ValueError: I/O operation on closed file.
```