ROLLOUT 0 · Pylons/waitress
pylons__waitress-249
Not solved
453 stotal time
14tool calls
14model calls
6,406tokens generated
126,138prompt tokens read
Empty agent patch
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System instructions 4,822 characters
You are a principal Python software engineer resolving a repository issue in `/workspace`. Your sole objective is to produce a minimal, root-cause source patch that passes every hidden fail-to-pass and pass-to-pass regression test on the first grading run. ## Critical Environment & Grader Rules 1. **Air-Gapped Sandbox & Available CLI Tools**: No network access. Never run `pip`, `uv`, `conda`, or `git fetch`. Note: `rg` (`ripgrep`) is NOT installed in the container — always use `grep -rn --include="*.py"` for fast exact searches so you never waste a tool call on `command not found`. 2. **Protected Grading Paths**: Before running official verification, the grading harness **strips and reverts all changes** to `tests/`, `test/`, `testing/`, `test_*.py`, `*_test.py`, `conftest.py`, `pyproject.toml`, `setup.cfg`, `pytest.ini`, and `tox.ini`. Every part of your fix MUST reside in non-test production source files. 3. **Untracked File Trap (`git add -N .`)**: `submit_patch` stages ALL untracked files inside `/workspace`! Never leave reproduction or scratch files inside `/workspace` — run reproductions inline via `python3 - <<'PY'` or inside `/tmp/repro.py` in a single `run_command`. 4. **Stdout Truncation Rule**: `run_command` truncates stdout after the first 5,000 characters from the TOP. Always run pytest quietly with short tracebacks: `pytest path/to/test_file.py -k pattern -q --tb=short --no-header` If a test file is large, redirect output to `/tmp/pytest.log` and inspect `tail -n 80 /tmp/pytest.log` so failure tracebacks at the bottom are never cut off. 5. **Strict Pacing Discipline**: `get_status` and `submit_patch` are free and do NOT count toward `max_tool_calls`. Target **16-22 counted tool calls total**, and **begin your first `edit_file` change no later than tool call 15**. Reserve at least 4 calls for verification, `git status --short && git diff`, and submission. ## Execution Protocol ### Phase 1 — Pinpoint Code & Tests Immediately (1-2 tool calls) - The user message already contains `Workspace Layout` — do NOT waste a turn running `ls` on top-level directories. - Run a single compound `run_command` with `grep -rn --include="*.py"` to locate: (a) the exact symbols, error strings, or functions from the problem description, (b) **all parallel or sibling implementations** (for example sync + async variants, `Client` + `AsyncClient`, serializer + deserializer, multiple backends/dialects, base + subclass methods, `__init__.py` / `__all__` exports), and (c) the closest existing unit test files under `tests/`. ### Phase 2 — Deep Read & Spec Anchor (2-5 tool calls) - Use `read_file` with generous `start_line` and `end_line` windows (180-300 lines per call so you read whole modules in fewer calls) on the target function/class, callers, type annotations, and neighboring tests. - Before editing, verify every explicit and implicit requirement from the issue: exact parameter names, defaults, boundary/domain edge cases, exception types/messages, `None` vs empty collection vs falsy (`0`, `False`, `""`) semantics, mutability/copying, and return types. ### Phase 3 — Reproduce Bug in One Call (1 tool call) - Run ONE concise command (`python3 - <<'PY' ... PY` or targeted `pytest ... -q --tb=short --no-header`) via `run_command` to observe the exact pre-fix failure. Do NOT spend multiple tool calls writing separate reproduction scripts. ### Phase 4 — Surgical Implementation Across All Parallel Paths (1-4 tool calls) - Begin editing by tool call 15! Use `edit_file` with 4-6 lines of exact surrounding context copied from `read_file`. - Update ALL parallel codepaths (sync/async, multiple classes/dialects, type hints) consistently so partial fixes do not fail sibling tests. - **2-Strike Edit Rule**: If `edit_file` fails twice on the same block due to whitespace or escaping, do not retry `edit_file` a third time — apply an atomic Python transformation via `run_command` and immediately verify `python3 -m py_compile path/to/file.py`. ### Phase 5 — Edge-Case Verification, Diff Hygiene & Clean Exit (2-4 tool calls) - Run a single compound `run_command` testing both your reproduction + boundary edge cases (`None`, empty input, leading/trailing delimiters, subdomain/prefix boundaries, subclass/async parity) AND the relevant existing `pytest` module(s) with `-q --tb=short --no-header`. - Run `git status --short && git diff` via `run_command`. Confirm: - ZERO untracked (`??`) files in `/workspace` (`rm -f` any untracked workspace files immediately), - ZERO modifications to `tests/` or protected config files (`git checkout -- tests/` if touched), - Minimal, clean diff with valid imports and indentation. - Call `submit_patch` once verification passes, then respond with a brief 2-sentence plain-text summary and make NO further tool calls.
Task prompt 3,378 characters
You are evaluating a software engineering task for repository Pylons/waitress. Problem Statement: ReadOnlyFileBasedBuffer does not work with io.IOBase subclasses ReadOnlyFileBasedBuffer checks if it can detect the file length by using `seek` and `tell` methods. While it checks for the file to be able to provide them at https://github.com/Pylons/waitress/blob/master/waitress/buffers.py#L140 it doesn't actually check if those can be used. In `io.IOBase` subclasses that are not seekable, those two methods exist but raise an `UnsupportedOperation`, in case of io.IOBase instance `.seekable` should probably be checked for `True` or the `UnsupportedOperation` should be trapped. Currently waitress is just crashing if it receives an `io.IOBase` subclasses which is not seekable as the file to serve. ## Task Budget (Session terminates when any budget is exhausted) - Time allowance: 7.5 minutes - Tool calls allowance: 30 calls - Max loop iterations: 40 turns ## Execution Environment Rules - Single command timeout: 90 seconds (commands exceeding this fail without ending the session) - Command output limit: 5000 characters - File view limit: 150 lines per read_file call - File character limit: 10000 characters per read_file call - Environment is offline (no network/PyPI access). All repository and test dependencies are ALREADY pre-installed. Do NOT attempt to run pip install or download packages. ## Instructions: 0. All source code is under `/workspace`. Do NOT search outside `/workspace` (e.g. `/usr/`, `/wheels/`, system site-packages). If imports fail, the issue is in the source code under `/workspace`, not in missing system packages. 1. Analyze the problem statement and any provided hints carefully to identify all requested script paths, CLI subcommands, or Python modules. 2. Inspect existing codebase conventions and test files before making edits. 3. Verify your implementation using targeted tests or inline assertions before submitting. 4. Call submit_patch only after your implementation is complete and verified. 5. As your final action, you must return a text-only response reporting your completion to terminate the session. ## Workspace Layout The repository is located at `/workspace`. Here is the directory tree (up to 3 levels): ``` ./CHANGES.txt ./CONTRIBUTORS.txt ./COPYRIGHT.txt ./HISTORY.txt ./LICENSE.txt ./README.rst ./RELEASING.txt ./TODO.txt ./appveyor.yml ./contributing.md ./docs ./rtd.txt ./setup.cfg ./setup.py ./tox.ini ./waitress ./waitress/__init__.py ./waitress/__main__.py ./waitress/adjustments.py ./waitress/buffers.py ./waitress/channel.py ./waitress/compat.py ./waitress/parser.py ./waitress/receiver.py ./waitress/runner.py ./waitress/server.py ./waitress/task.py ./waitress/tests ./waitress/tests/__init__.py ./waitress/tests/fixtureapps ./waitress/tests/test_adjustments.py ./waitress/tests/test_buffers.py ./waitress/tests/test_channel.py ./waitress/tests/test_compat.py ./waitress/tests/test_functional.py ./waitress/tests/test_init.py ./waitress/tests/test_parser.py ./waitress/tests/test_receiver.py ./waitress/tests/test_regression.py ./waitress/tests/test_runner.py ./waitress/tests/test_server.py ./waitress/tests/test_task.py ./waitress/tests/test_trigger.py ./waitress/tests/test_utilities.py ./waitress/tests/test_wasyncore.py ./waitress/trigger.py ./waitress/utilities.py ./waitress/wasyncore.py ```
Turn 1at 18 s265 tokens out2,978 prompt tokens
The user is reporting a bug in `ReadOnlyFileBasedBuffer` in `waitress/buffers.py`. The issue is that it checks for the presence of `seek` and `tell` methods on the file-like object, but it doesn't check if they are actually supported (i.e., if they raise `io.UnsupportedOperation`). For `io.IOBase` subclasses that are not seekable, `seek` and `tell` might exist but will raise `UnsupportedOperation`. The suggested fix is to check `.seekable()` or catch `UnsupportedOperation`. I need to: 1. Examine `waitress/buffers.py` around line 140 to see how `ReadOnlyFileBasedBuffer` checks for `seek` and `tell`. 2. Create a reproduction script that uses a non-seekable `io.IOBase` subclass and passes it to `ReadOnlyFileBasedBuffer`. 3. Fix the bug by checking `.seekable()` or catching `UnsupportedOperation`. 4. Verify the fix with the reproduction script and existing tests.
TOOL CALL · read_file
{
"end_line": 200,
"filepath": "waitress/buffers.py",
"start_line": 100
}Result of read_file 2,999 characters
{
"status": "ok",
"filepath": "waitress/buffers.py",
"content": " nf.write(data)\n self.file = nf\n\n def getfile(self):\n return self.file\n\n def close(self):\n if hasattr(self.file, 'close'):\n self.file.close()\n self.remain = 0\n\nclass TempfileBasedBuffer(FileBasedBuffer):\n\n def __init__(self, from_buffer=None):\n FileBasedBuffer.__init__(self, self.newfile(), from_buffer)\n\n def newfile(self):\n from tempfile import TemporaryFile\n return TemporaryFile('w+b')\n\nclass BytesIOBasedBuffer(FileBasedBuffer):\n\n def __init__(self, from_buffer=None):\n if from_buffer is not None:\n FileBasedBuffer.__init__(self, BytesIO(), from_buffer)\n else:\n # Shortcut. :-)\n self.file = BytesIO()\n\n def newfile(self):\n return BytesIO()\n\nclass ReadOnlyFileBasedBuffer(FileBasedBuffer):\n # used as wsgi.file_wrapper\n\n def __init__(self, file, block_size=32768):\n self.file = file\n self.block_size = block_size # for __iter__\n\n def prepare(self, size=None):\n if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):\n start_pos = self.file.tell()\n self.file.seek(0, 2)\n end_pos = self.file.tell()\n self.file.seek(start_pos)\n fsize = end_pos - start_pos\n if size is None:\n self.remain = fsize\n else:\n self.remain = min(fsize, size)\n return self.remain\n\n def get(self, numbytes=-1, skip=False):\n # never read more than self.remain (it can be user-specified)\n if numbytes == -1 or numbytes > self.remain:\n numbytes = self.remain\n file = self.file\n if not skip:\n read_pos = file.tell()\n res = file.read(numbytes)\n if skip:\n self.remain -= len(res)\n else:\n file.seek(read_pos)\n return res\n\n def __iter__(self): # called by task if self.filelike has no seek/tell\n return self\n\n def next(self):\n val = self.file.read(self.block_size)\n if not val:\n raise StopIteration\n return val\n\n __next__ = next # py3\n\n def append(self, s):\n raise NotImplementedError\n\nclass OverflowableBuffer(object):\n \"\"\"\n This buffer implementation has four stages:\n - No data\n - Bytes-based buffer\n - BytesIO-based buffer\n - Temporary file storage\n The first two stages are fastest for simple transfers.\n \"\"\"\n\n overflowed = False\n buf = None\n strbuf = b'' # Bytes-based buffer.\n\n def __init__(self, overflow):\n # overflow is the maximum to be stored in a StringIO buffer.\n self.overflow = overflow\n\n def __len__(self):\n buf = self.buf\n if buf is not None:",
"start_line": 100,
"end_line": 200,
"total_lines": 298,
"is_truncated": false
}Generated tokens 265 tokens · stopped: STOP
<|channel>thought
The user is reporting a bug in `ReadOnlyFileBasedBuffer` in `waitress/buffers.py`.
The issue is that it checks for the presence of `seek` and `tell` methods on the file-like object, but it doesn't check if they are actually supported (i.e., if they raise `io.UnsupportedOperation`).
For `io.IOBase` subclasses that are not seekable, `seek` and `tell` might exist but will raise `UnsupportedOperation`.
The suggested fix is to check `.seekable()` or catch `UnsupportedOperation`.
I need to:
1. Examine `waitress/buffers.py` around line 140 to see how `ReadOnlyFileBasedBuffer` checks for `seek` and `tell`.
2. Create a reproduction script that uses a non-seekable `io.IOBase` subclass and passes it to `ReadOnlyFileBasedBuffer`.
3. Fix the bug by checking `.seekable()` or catching `UnsupportedOperation`.
4. Verify the fix with the reproduction script and existing tests.<channel|><|tool_call>call:read_file{filepath:<|"|>waitress/buffers.py<|"|>,start_line:100,end_line:200}<tool_call|><|tool_response>
Turn 2at 64 s614 tokens out4,161 prompt tokens
The code in `ReadOnlyFileBasedBuffer.prepare` (lines 140-149):
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
return self.remain
```
It checks `hasattr(self.file, 'seek')` and `hasattr(self.file, 'tell')`.
However, many `io` objects have these methods but they raise `UnsupportedOperation` if the object is not seekable.
I will create a reproduction script. I can use `io.BufferedReader` wrapped around a non-seekable stream, or just create a custom class that inherits from `io.IOBase` and implements `seek`/`tell` but raises `UnsupportedOperation`. Actually, `io.BytesIO` is seekable. `sys.stdin` or `sys.stdout` might be non-seekable, but we cannot easily use them.
A better way is to create a class that inherits from `io.RawIOBase` or `io.IOBase` and implement `seek` and `tell` to raise `io.UnsupportedOperation`.
Wait, `io.BufferedReader`'s `seekable()` method returns `True` if it can seek.
If I create a class that has `seek` and `tell` but they raise `UnsupportedOperation`, then `ReadOnlyFileBasedBuffer.prepare` should not try to use them.
Let's try this reproduction:
TOOL CALL · run_command
{
"command": "python3 - <<'PY'\nimport io\nfrom waitress.buffers import ReadOnlyFileBasedBuffer\n\nclass NonSeekableFile(io.IOBase):\n def tell(self):\n raise io.UnsupportedOperation(\"operation not supported\")\n def seek(self, offset, whence=io.SEEK_SET):\n raise io.UnsupportedOperation(\"operation not supported\")\n def read(self, size=-1):\n return b\"hello world\"\n\nfile = NonSeekableFile()\nbuffer = ReadOnlyFileBasedBuffer(file)\ntry:\n buffer.prepare()\n print(\"Success\")\nexcept io.UnsupportedOperation:\n print(\"Caught expected UnsupportedOperation\")\nexcept Exception as e:\n print(f\"Caught unexpected exception: {type(e).__name__}: {e}\")\nPY\n"
}Result of run_command 98 characters
{
"status": "ok",
"stdout": "Caught expected UnsupportedOperation\n",
"stderr": "",
"exit_code": 0
}Generated tokens 614 tokens · stopped: STOP
The code in `ReadOnlyFileBasedBuffer.prepare` (lines 140-149):
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
return self.remain
```
It checks `hasattr(self.file, 'seek')` and `hasattr(self.file, 'tell')`.
However, many `io` objects have these methods but they raise `UnsupportedOperation` if the object is not seekable.
I will create a reproduction script. I can use `io.BufferedReader` wrapped around a non-seekable stream, or just create a custom class that inherits from `io.IOBase` and implements `seek`/`tell` but raises `UnsupportedOperation`. Actually, `io.BytesIO` is seekable. `sys.stdin` or `sys.stdout` might be non-seekable, but we cannot easily use them.
A better way is to create a class that inherits from `io.RawIOBase` or `io.IOBase` and implement `seek` and `tell` to raise `io.UnsupportedOperation`.
Wait, `io.BufferedReader`'s `seekable()` method returns `True` if it can seek.
If I create a class that has `seek` and `tell` but they raise `UnsupportedOperation`, then `ReadOnlyFileBasedBuffer.prepare` should not try to use them.
Let's try this reproduction:
<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY'
import io
from waitress.buffers import ReadOnlyFileBasedBuffer
class NonSeekableFile(io.IOBase):
def tell(self):
raise io.UnsupportedOperation("operation not supported")
def seek(self, offset, whence=io.SEEK_SET):
raise io.UnsupportedOperation("operation not supported")
def read(self, size=-1):
return b"hello world"
file = NonSeekableFile()
buffer = ReadOnlyFileBasedBuffer(file)
try:
buffer.prepare()
print("Success")
except io.UnsupportedOperation:
print("Caught expected UnsupportedOperation")
except Exception as e:
print(f"Caught unexpected exception: {type(e).__name__}: {e}")
PY
<|"|>}<tool_call|><|tool_response>
Turn 3at 75 s269 tokens out4,819 prompt tokens
Okay, the reproduction confirmed that it raises `io.UnsupportedOperation`. Now let's check if we can use `seekable()`. `io.IOBase` has a `seekable()` method that returns `True` or `False`. Let's modify the reproduction script to check `seekable()` on our `NonSeekableFile`.
TOOL CALL · run_command
{
"command": "python3 - <<'PY'\nimport io\nfrom waitress.buffers import ReadOnlyFileBasedBuffer\n\nclass NonSeekableFile(io.IOBase):\n def tell(self):\n raise io.UnsupportedOperation(\"operation not supported\")\n def seek(self, offset, whence=io.SEEK_SET):\n raise io.UnsupportedOperation(\"operation not supported\")\n def read(self, size=-1):\n return b\"hello world\"\n def seekable(self):\n return False\n\nfile = NonSeekableFile()\nprint(f\"seekable: {file.seekable()}\")\nbuffer = ReadOnlyFileBasedBuffer(file)\ntry:\n buffer.prepare()\n print(\"Success\")\nexcept io.UnsupportedOperation:\n print(\"Caught expected UnsupportedOperation\")\nPY\n"
}Result of run_command 115 characters
{
"status": "ok",
"stdout": "seekable: False\nCaught expected UnsupportedOperation\n",
"stderr": "",
"exit_code": 0
}Generated tokens 269 tokens · stopped: STOP
Okay, the reproduction confirmed that it raises `io.UnsupportedOperation`.
Now let's check if we can use `seekable()`. `io.IOBase` has a `seekable()` method that returns `True` or `False`.
Let's modify the reproduction script to check `seekable()` on our `NonSeekableFile`.
<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY'
import io
from waitress.buffers import ReadOnlyFileBasedBuffer
class NonSeekableFile(io.IOBase):
def tell(self):
raise io.UnsupportedOperation("operation not supported")
def seek(self, offset, whence=io.SEEK_SET):
raise io.UnsupportedOperation("operation not supported")
def read(self, size=-1):
return b"hello world"
def seekable(self):
return False
file = NonSeekableFile()
print(f"seekable: {file.seekable()}")
buffer = ReadOnlyFileBasedBuffer(file)
try:
buffer.prepare()
print("Success")
except io.UnsupportedOperation:
print("Caught expected UnsupportedOperation")
PY
<|"|>}<tool_call|><|tool_response>
Turn 4at 109 s562 tokens out5,138 prompt tokens
The issue is that `ReadOnlyFileBasedBuffer.prepare` only checks for the presence of the methods, not whether they are actually supported.
The proposed fix is either to check `seekable()` or to trap `UnsupportedOperation`.
If we check `seekable()`, we still need to make sure that `seekable` method exists.
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
# ...
```
If we change it to:
```python
def prepare(self, size=None):
if getattr(self.file, 'seekable', lambda: False)():
# ...
```
Wait, if `seekable()` returns `True`, then `seek` and `tell` should be available and working.
Actually, if `seekable()` is available and returns `True`, it's safer to use it.
However, some file-like objects might have `seek` and `tell` but not `seekable()`. In those cases, we might still want to try using them, and catch `UnsupportedOperation`.
The problem statement says:
"In `io.IOBase` subclasses that are not seekable, those two methods exist but raise an `UnsupportedOperation`, in case of io.IOBase instance `.seekable` should probably be checked for `True` or the `UnsupportedOperation` should be trapped."
Let's see what happens if we just wrap the block in a `try...except io.UnsupportedOperation`.
Wait, if we catch `UnsupportedOperation`, what should `self.remain` be?
In the current code:
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
# ...
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
return self.remain
```
If the `if` block is skipped, `self.remain` is not initialized (unless it was already there).
Actually, `ReadOnlyFileBasedBuffer.__init__` does NOT initialize `self.remain`.
Wait, `ReadOnlyFileBasedBuffer` inherits from `FileBasedBuffer`.
Let's check `FileBasedBuffer`. I'll read the top of `waitress/buffers.py`.
TOOL CALL · read_file
{
"end_line": 100,
"filepath": "waitress/buffers.py",
"start_line": 1
}Result of read_file 3,178 characters
{
"status": "ok",
"filepath": "waitress/buffers.py",
"content": "##############################################################################\n#\n# Copyright (c) 2001-2004 Zope Foundation and Contributors.\n# All Rights Reserved.\n#\n# This software is subject to the provisions of the Zope Public License,\n# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.\n# THIS SOFTWARE IS PROVIDED \"AS IS\" AND ANY AND ALL EXPRESS OR IMPLIED\n# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED\n# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS\n# FOR A PARTICULAR PURPOSE.\n#\n##############################################################################\n\"\"\"Buffers\n\"\"\"\nfrom io import BytesIO\n\n# copy_bytes controls the size of temp. strings for shuffling data around.\nCOPY_BYTES = 1 << 18 # 256K\n\n# The maximum number of bytes to buffer in a simple string.\nSTRBUF_LIMIT = 8192\n\nclass FileBasedBuffer(object):\n\n remain = 0\n\n def __init__(self, file, from_buffer=None):\n self.file = file\n if from_buffer is not None:\n from_file = from_buffer.getfile()\n read_pos = from_file.tell()\n from_file.seek(0)\n while True:\n data = from_file.read(COPY_BYTES)\n if not data:\n break\n file.write(data)\n self.remain = int(file.tell() - read_pos)\n from_file.seek(read_pos)\n file.seek(read_pos)\n\n def __len__(self):\n return self.remain\n\n def __nonzero__(self):\n return True\n\n __bool__ = __nonzero__ # py3\n\n def append(self, s):\n file = self.file\n read_pos = file.tell()\n file.seek(0, 2)\n file.write(s)\n file.seek(read_pos)\n self.remain = self.remain + len(s)\n\n def get(self, numbytes=-1, skip=False):\n file = self.file\n if not skip:\n read_pos = file.tell()\n if numbytes < 0:\n # Read all\n res = file.read()\n else:\n res = file.read(numbytes)\n if skip:\n self.remain -= len(res)\n else:\n file.seek(read_pos)\n return res\n\n def skip(self, numbytes, allow_prune=0):\n if self.remain < numbytes:\n raise ValueError(\"Can't skip %d bytes in buffer of %d bytes\" % (\n numbytes, self.remain)\n )\n self.file.seek(numbytes, 1)\n self.remain = self.remain - numbytes\n\n def newfile(self):\n raise NotImplementedError()\n\n def prune(self):\n file = self.file\n if self.remain == 0:\n read_pos = file.tell()\n file.seek(0, 2)\n sz = file.tell()\n file.seek(read_pos)\n if sz == 0:\n # Nothing to prune.\n return\n nf = self.newfile()\n while True:\n data = file.read(COPY_BYTES)\n if not data:\n break\n nf.write(data)",
"start_line": 1,
"end_line": 100,
"total_lines": 298,
"is_truncated": false
}Generated tokens 562 tokens · stopped: STOP
The issue is that `ReadOnlyFileBasedBuffer.prepare` only checks for the presence of the methods, not whether they are actually supported.
The proposed fix is either to check `seekable()` or to trap `UnsupportedOperation`.
If we check `seekable()`, we still need to make sure that `seekable` method exists.
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
# ...
```
If we change it to:
```python
def prepare(self, size=None):
if getattr(self.file, 'seekable', lambda: False)():
# ...
```
Wait, if `seekable()` returns `True`, then `seek` and `tell` should be available and working.
Actually, if `seekable()` is available and returns `True`, it's safer to use it.
However, some file-like objects might have `seek` and `tell` but not `seekable()`. In those cases, we might still want to try using them, and catch `UnsupportedOperation`.
The problem statement says:
"In `io.IOBase` subclasses that are not seekable, those two methods exist but raise an `UnsupportedOperation`, in case of io.IOBase instance `.seekable` should probably be checked for `True` or the `UnsupportedOperation` should be trapped."
Let's see what happens if we just wrap the block in a `try...except io.UnsupportedOperation`.
Wait, if we catch `UnsupportedOperation`, what should `self.remain` be?
In the current code:
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
# ...
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
return self.remain
```
If the `if` block is skipped, `self.remain` is not initialized (unless it was already there).
Actually, `ReadOnlyFileBasedBuffer.__init__` does NOT initialize `self.remain`.
Wait, `ReadOnlyFileBasedBuffer` inherits from `FileBasedBuffer`.
Let's check `FileBasedBuffer`. I'll read the top of `waitress/buffers.py`.<channel|><|tool_call>call:read_file{end_line:100,filepath:<|"|>waitress/buffers.py<|"|>,start_line:1}<tool_call|><|tool_response>
Turn 5at 142 s496 tokens out6,633 prompt tokens
`FileBasedBuffer` defines `remain = 0` as a class attribute.
So in `ReadOnlyFileBasedBuffer.prepare`:
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
# ... (sets self.remain)
return self.remain
```
If the block is skipped, it returns `self.remain` which is 0 if not previously set.
If `ReadOnlyFileBasedBuffer` is used, `self.remain` starts at 0. If we cannot determine the size, `self.remain` stays 0.
Is that correct for a read-only file based buffer?
If `self.remain` is 0, then `get(numbytes=-1)` will return `numbytes = 0` bytes because:
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
# ...
```
So if `self.remain` is 0, `get` returns an empty string. That seems wrong if the file actually has content but we just couldn't determine its size.
Wait, `ReadOnlyFileBasedBuffer` also has `__iter__` and `next`:
```python
def __iter__(self): # called by task if self.filelike has no seek/tell
return self
def next(self):
val = self.file.read(self.block_size)
if not val:
raise StopIteration
return val
__next__ = next # py3
```
The comment `# called by task if self.filelike has no seek/tell` suggests that if the buffer doesn't support the `get` method efficiently (which depends on `remain`), the `task` might use the iterator instead.
Let's check `waitress/task.py` to see how `ReadOnlyFileBasedBuffer` is used.
TOOL CALL · run_command
{
"command": "grep -rn \"ReadOnlyFileBasedBuffer\" waitress/task.py"
}Result of run_command 239 characters
{
"status": "ok",
"stdout": "21:from .buffers import ReadOnlyFileBasedBuffer\n451: if app_iter.__class__ is ReadOnlyFileBasedBuffer:\n788: 'wsgi.file_wrapper': ReadOnlyFileBasedBuffer,\n",
"stderr": "",
"exit_code": 0
}Generated tokens 496 tokens · stopped: STOP
`FileBasedBuffer` defines `remain = 0` as a class attribute.
So in `ReadOnlyFileBasedBuffer.prepare`:
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
# ... (sets self.remain)
return self.remain
```
If the block is skipped, it returns `self.remain` which is 0 if not previously set.
If `ReadOnlyFileBasedBuffer` is used, `self.remain` starts at 0. If we cannot determine the size, `self.remain` stays 0.
Is that correct for a read-only file based buffer?
If `self.remain` is 0, then `get(numbytes=-1)` will return `numbytes = 0` bytes because:
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
# ...
```
So if `self.remain` is 0, `get` returns an empty string. That seems wrong if the file actually has content but we just couldn't determine its size.
Wait, `ReadOnlyFileBasedBuffer` also has `__iter__` and `next`:
```python
def __iter__(self): # called by task if self.filelike has no seek/tell
return self
def next(self):
val = self.file.read(self.block_size)
if not val:
raise StopIteration
return val
__next__ = next # py3
```
The comment `# called by task if self.filelike has no seek/tell` suggests that if the buffer doesn't support the `get` method efficiently (which depends on `remain`), the `task` might use the iterator instead.
Let's check `waitress/task.py` to see how `ReadOnlyFileBasedBuffer` is used.<channel|><|tool_call>call:run_command{command:<|"|>grep -rn "ReadOnlyFileBasedBuffer" waitress/task.py<|"|>}<tool_call|><|tool_response>
Turn 6at 146 s57 tokens out7,221 prompt tokens
Let's see `waitress/task.py` around line 451.
TOOL CALL · read_file
{
"end_line": 480,
"filepath": "waitress/task.py",
"start_line": 430
}Result of read_file 2,543 characters
{
"status": "ok",
"filepath": "waitress/task.py",
"content": " raise ValueError(\"carriage return/line \"\n \"feed character present in header name\")\n\n kl = k.lower()\n if kl == 'content-length':\n self.content_length = int(v)\n elif kl in hop_by_hop:\n raise AssertionError(\n '%s is a \"hop-by-hop\" header; it cannot be used by '\n 'a WSGI application (see PEP 3333)' % k)\n\n self.response_headers.extend(headers)\n\n # Return a method used to write the response data.\n return self.write\n\n # Call the application to handle the request and write a response\n app_iter = self.channel.server.application(env, start_response)\n\n can_close_app_iter = True\n try:\n if app_iter.__class__ is ReadOnlyFileBasedBuffer:\n cl = self.content_length\n size = app_iter.prepare(cl)\n if size:\n if cl != size:\n if cl is not None:\n self.remove_content_length_header()\n self.content_length = size\n self.write(b'') # generate headers\n # if the write_soon below succeeds then the channel will\n # take over closing the underlying file via the channel's\n # _flush_some or handle_close so we intentionally avoid\n # calling close in the finally block\n self.channel.write_soon(app_iter)\n can_close_app_iter = False\n return\n\n first_chunk_len = None\n for chunk in app_iter:\n if first_chunk_len is None:\n first_chunk_len = len(chunk)\n # Set a Content-Length header if one is not supplied.\n # start_response may not have been called until first\n # iteration as per PEP, so we must reinterrogate\n # self.content_length here\n if self.content_length is None:\n app_iter_len = None\n if hasattr(app_iter, '__len__'):\n app_iter_len = len(app_iter)\n if app_iter_len == 1:",
"start_line": 430,
"end_line": 480,
"total_lines": 833,
"is_truncated": false
}Generated tokens 57 tokens · stopped: STOP
Let's see `waitress/task.py` around line 451.
<channel|><|tool_call>call:read_file{end_line:480,filepath:<|"|>waitress/task.py<|"|>,start_line:430}<tool_call|><|tool_response>
Turn 7at 224 s1,124 tokens out7,891 prompt tokens
Yes, in `task.py`:
```python
if app_iter.__class__ is ReadOnlyFileBasedBuffer:
cl = self.content_length
size = app_iter.prepare(cl)
if size:
# ...
self.channel.write_soon(app_iter)
can_close_app_iter = False
return
```
If `size` (which is `app_iter.prepare(cl)`) is 0 or None, it falls through to the `for chunk in app_iter:` loop.
And `ReadOnlyFileBasedBuffer` implements `__iter__` and `__next__`, which just read from the file in `block_size` chunks.
So if `prepare()` fails to determine the size (returns 0), the `task` will still be able to serve the file by iterating over it.
The issue is that `prepare()` crashes if `seek` or `tell` exist but are not supported.
If I change `prepare()` to:
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
try:
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
except (io.UnsupportedOperation, AttributeError):
pass
return self.remain
```
Wait, `io` might not be imported in `buffers.py`. Let's check imports in `buffers.py`.
It imports `BytesIO` from `io`. I should check if I can import `io`.
Wait, `waitress/buffers.py` only has `from io import BytesIO`. I need to import `io` or `UnsupportedOperation`.
Let's check if `io.UnsupportedOperation` is available in `waitress/compat.py` or similar.
Anyway, I can just import `io` at the top of `buffers.py` or inside `prepare`.
Actually, importing it at the top is cleaner.
Wait, if I use `getattr(self.file, 'seekable', lambda: False)()`, it might be cleaner for `io.IOBase` subclasses. But some other file-like objects might not have `seekable()`.
The problem statement specifically mentions `io.IOBase`.
If I use a `try...except` block, I need to catch `io.UnsupportedOperation`.
Let's see if there is another way to detect if seek is supported.
`io.IOBase.seekable()` is the standard way.
If the object is not an `io.IOBase` instance, it might still have `seek` and `tell`.
Let's try to use both: check `seekable()` if it exists, otherwise try the `seek`/`tell` approach and catch `UnsupportedOperation`.
Wait, `io.UnsupportedOperation` is just an alias for `OSError` in some Python versions, or a subclass of it.
Actually, it's better to just wrap the seek/tell logic in a `try...except (io.UnsupportedOperation, AttributeError)`.
Wait, `AttributeError` wouldn't happen since I already checked `hasattr`.
But `UnsupportedOperation` would.
One more thing: Does `ReadOnlyFileBasedBuffer.get` also need the same fix?
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
file = self.file
if not skip:
read_pos = file.tell()
res = file.read(numbytes)
if skip:
self.remain -= len(res)
else:
file.seek(read_pos)
return res
```
`get` also uses `tell` and `seek`.
If `prepare()` was successful, `self.remain` was set to something > 0.
But `prepare()` was successful only if `tell` and `seek` worked.
So if `prepare()` succeeded, `get()` should work too.
Wait, if `prepare()` was NOT called, `self.remain` is 0.
If `get()` is called with `numbytes=-1`, `numbytes` becomes `self.remain` which is 0.
And it returns `file.read(0)`.
Wait, when is `get()` called? I haven't seen it called in `task.py`.
Let's search for `.get(` in `waitress/`.
TOOL CALL · run_command
{
"command": "grep -rn \"\\.get(\" waitress/"
}Result of run_command 5,128 characters
{
"status": "ok",
"stdout": "waitress/parser.py:210: connection = headers.get('CONNECTION', '')\nwaitress/parser.py:226: expect = headers.get('EXPECT', '').lower()\nwaitress/parser.py:233: cl = int(headers.get('CONTENT_LENGTH', 0))\nwaitress/adjustments.py:466: kw['listen'] = '{} {}'.format(kw.get('listen', ''), value)\nwaitress/wasyncore.py:160: obj = map.get(fd)\nwaitress/wasyncore.py:166: obj = map.get(fd)\nwaitress/wasyncore.py:172: obj = map.get(fd)\nwaitress/wasyncore.py:204: obj = map.get(fd)\nwaitress/wasyncore.py:455: self.logger.log(severity.get(type, logging.INFO), message)\nwaitress/buffers.py:257: return buf.get(numbytes, skip)\nwaitress/channel.py:228: chunk = outbuf.get(self.sendbuf_len)\nwaitress/task.py:195: connection = self.request.headers.get('CONNECTION', '').lower()\nwaitress/task.py:369: connection = self.request.headers.get('CONNECTION', '').lower()\nwaitress/task.py:563: forwarded_proto = undquote(headers.get(\"X_FORWARDED_PROTO\", \"\"))\nwaitress/task.py:571: forwarded_port = undquote(headers.get(\"X_FORWARDED_PORT\", \"\"))\nwaitress/task.py:584: forwarded = headers.get(\"FORWARDED\", None)\nwaitress/task.py:825: mykey = rename_headers.get(key, None)\nwaitress/tests/fixtureapps/nocl.py:12: cl = environ.get('CONTENT_LENGTH', None)\nwaitress/tests/fixtureapps/echo.py:2: cl = environ.get('CONTENT_LENGTH', None)\nwaitress/tests/fixtureapps/error.py:2: cl = environ.get('CONTENT_LENGTH', None)\nwaitress/tests/test_buffers.py:46: result = inst.get(100, skip=True)\nwaitress/tests/test_buffers.py:53: result = inst.get(100, skip=False)\nwaitress/tests/test_buffers.py:60: result = inst.get(-1, skip=False)\nwaitress/tests/test_buffers.py:180: result = inst.get(-1)\nwaitress/tests/test_buffers.py:189: result = inst.get(3)\nwaitress/tests/test_buffers.py:198: result = inst.get(1)\nwaitress/tests/test_buffers.py:207: result = inst.get(3, skip=True)\nwaitress/tests/test_buffers.py:216: result = inst.get(1, skip=True)\nwaitress/tests/test_buffers.py:274: self.assertEqual(inst.buf.get(100), b'x' * 11)\nwaitress/tests/test_buffers.py:283: self.assertEqual(inst.buf.get(100), b'x' * 5)\nwaitress/tests/test_buffers.py:332: r = inst.get(5)\nwaitress/tests/test_buffers.py:338: r = inst.get(5, skip=True)\nwaitress/tests/test_wasyncore.py:66: registry = frame.f_globals.get('__warningregistry__')\nwaitress/tests/test_wasyncore.py:112: quiet = kwargs.get('quiet')\nwaitress/tests/test_functional.py:69: self.bound_to = self.queue.get(timeout=5)\nwaitress/tests/test_functional.py:154: self.assertEqual(headers.get('server'), 'waitress')\nwaitress/tests/test_functional.py:155: self.assertTrue(headers.get('date'))\nwaitress/tests/test_functional.py:167: self.assertEqual(headers.get('server'), 'waitress')\nwaitress/tests/test_functional.py:168: self.assertTrue(headers.get('date'))\nwaitress/tests/test_functional.py:180: self.assertEqual(headers.get('content-length'), '5')\nwaitress/tests/test_functional.py:192: self.assertEqual(headers.get('content-length'), '0')\nwaitress/tests/test_functional.py:239: self.assertEqual(headers.get('content-length'), '1024')\nwaitress/tests/test_functional.py:439: length = int(headers.get('content-length')) or None\nwaitress/tests/test_functional.py:477: length = int(headers.get('content-length')) or None\nwaitress/tests/test_functional.py:507: content_length = int(headers.get('content-length'))\nwaitress/tests/test_functional.py:533: content_length = int(headers.get('content-length')) or None\nwaitress/tests/test_functional.py:544: content_length = int(headers.get('content-length')) or None\nwaitress/tests/test_functional.py:569: self.assertEqual(headers.get('content-length'), None)\nwaitress/tests/test_functional.py:570: self.assertEqual(headers.get('connection'), 'close')\nwaitress/tests/test_functional.py:590: self.assertEqual(headers.get('connection'), 'Keep-Alive')\nwaitress/tests/test_functional.py:610: self.assertEqual(headers.get('content-length'), None)\nwaitress/tests/test_functional.py:611: self.assertEqual(headers.get('connection'), 'close')\nwaitress/tests/test_functional.py:727: content_length = int(headers.get('content-length')) or None\nwaitress/tests/test_functional.py:750: content_length = int(headers.get('content-length')) or None\nwaitress/tests/test_functional.py:774: content_length = headers.get('content-length')\nwaitress/tests/test_channel.py:246: self.assertEqual(inst.outbufs[0].get(), b'')\nwaitress/tests/test_channel.py:247: self.assertEqual(inst.outbufs[1].get(), b'xyz')\nwaitress/tests/test_channel.py:262: self.assertEqual(inst.outbufs[0].get(), b'')\nwaitress/tests/test_channel.py:263: self.ass",
"stderr": "",
"exit_code": 0
}Generated tokens 1,124 tokens · stopped: STOP
Yes, in `task.py`:
```python
if app_iter.__class__ is ReadOnlyFileBasedBuffer:
cl = self.content_length
size = app_iter.prepare(cl)
if size:
# ...
self.channel.write_soon(app_iter)
can_close_app_iter = False
return
```
If `size` (which is `app_iter.prepare(cl)`) is 0 or None, it falls through to the `for chunk in app_iter:` loop.
And `ReadOnlyFileBasedBuffer` implements `__iter__` and `__next__`, which just read from the file in `block_size` chunks.
So if `prepare()` fails to determine the size (returns 0), the `task` will still be able to serve the file by iterating over it.
The issue is that `prepare()` crashes if `seek` or `tell` exist but are not supported.
If I change `prepare()` to:
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
try:
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
except (io.UnsupportedOperation, AttributeError):
pass
return self.remain
```
Wait, `io` might not be imported in `buffers.py`. Let's check imports in `buffers.py`.
It imports `BytesIO` from `io`. I should check if I can import `io`.
Wait, `waitress/buffers.py` only has `from io import BytesIO`. I need to import `io` or `UnsupportedOperation`.
Let's check if `io.UnsupportedOperation` is available in `waitress/compat.py` or similar.
Anyway, I can just import `io` at the top of `buffers.py` or inside `prepare`.
Actually, importing it at the top is cleaner.
Wait, if I use `getattr(self.file, 'seekable', lambda: False)()`, it might be cleaner for `io.IOBase` subclasses. But some other file-like objects might not have `seekable()`.
The problem statement specifically mentions `io.IOBase`.
If I use a `try...except` block, I need to catch `io.UnsupportedOperation`.
Let's see if there is another way to detect if seek is supported.
`io.IOBase.seekable()` is the standard way.
If the object is not an `io.IOBase` instance, it might still have `seek` and `tell`.
Let's try to use both: check `seekable()` if it exists, otherwise try the `seek`/`tell` approach and catch `UnsupportedOperation`.
Wait, `io.UnsupportedOperation` is just an alias for `OSError` in some Python versions, or a subclass of it.
Actually, it's better to just wrap the seek/tell logic in a `try...except (io.UnsupportedOperation, AttributeError)`.
Wait, `AttributeError` wouldn't happen since I already checked `hasattr`.
But `UnsupportedOperation` would.
One more thing: Does `ReadOnlyFileBasedBuffer.get` also need the same fix?
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
file = self.file
if not skip:
read_pos = file.tell()
res = file.read(numbytes)
if skip:
self.remain -= len(res)
else:
file.seek(read_pos)
return res
```
`get` also uses `tell` and `seek`.
If `prepare()` was successful, `self.remain` was set to something > 0.
But `prepare()` was successful only if `tell` and `seek` worked.
So if `prepare()` succeeded, `get()` should work too.
Wait, if `prepare()` was NOT called, `self.remain` is 0.
If `get()` is called with `numbytes=-1`, `numbytes` becomes `self.remain` which is 0.
And it returns `file.read(0)`.
Wait, when is `get()` called? I haven't seen it called in `task.py`.
Let's search for `.get(` in `waitress/`.
<channel|><|tool_call>call:run_command{command:<|"|>grep -rn "\.get(" waitress/<|"|>}<tool_call|><|tool_response>
Turn 8at 231 s99 tokens out10,812 prompt tokens
`waitress/channel.py:228` calls `outbuf.get(self.sendbuf_len)`. `outbuf` is likely an `OverflowableBuffer`. Let's check `OverflowableBuffer.get` in `waitress/buffers.py`.
TOOL CALL · read_file
{
"end_line": 265,
"filepath": "waitress/buffers.py",
"start_line": 240
}Result of read_file 1,062 characters
{
"status": "ok",
"filepath": "waitress/buffers.py",
"content": " return\n buf = self._create_buffer()\n buf.append(s)\n # use buf.__len__ rather than len(buf) FBO of not getting\n # OverflowError on Python 2\n sz = buf.__len__()\n if not self.overflowed:\n if sz >= self.overflow:\n self._set_large_buffer()\n\n def get(self, numbytes=-1, skip=False):\n buf = self.buf\n if buf is None:\n strbuf = self.strbuf\n if not skip:\n return strbuf\n buf = self._create_buffer()\n return buf.get(numbytes, skip)\n\n def skip(self, numbytes, allow_prune=False):\n buf = self.buf\n if buf is None:\n if allow_prune and numbytes == len(self.strbuf):\n # We could slice instead of converting to\n # a buffer, but that would eat up memory in\n # large transfers.",
"start_line": 240,
"end_line": 265,
"total_lines": 298,
"is_truncated": false
}Generated tokens 99 tokens · stopped: STOP
`waitress/channel.py:228` calls `outbuf.get(self.sendbuf_len)`.
`outbuf` is likely an `OverflowableBuffer`.
Let's check `OverflowableBuffer.get` in `waitress/buffers.py`.
<channel|><|tool_call>call:read_file{end_line:265,filepath:<|"|>waitress/buffers.py<|"|>,start_line:240}<tool_call|><|tool_response>
Turn 9at 261 s526 tokens out11,232 prompt tokens
`OverflowableBuffer.get` calls `buf.get(numbytes, skip)`.
`buf` can be `BytesIOBasedBuffer` or `TempfileBasedBuffer` (which both inherit from `FileBasedBuffer`).
`FileBasedBuffer.get` uses `tell` and `seek`.
```python
def get(self, numbytes=-1, skip=False):
file = self.file
if not skip:
read_pos = file.tell()
if numbytes < 0:
# Read all
res = file.read()
else:
res = file.read(numbytes)
if skip:
self.remain -= len(res)
else:
file.seek(read_pos)
return res
```
However, `BytesIO` and `TemporaryFile` are always seekable. So `FileBasedBuffer` is fine.
The issue is specifically with `ReadOnlyFileBasedBuffer`, because it takes an arbitrary `file` object in `__init__`.
Let's check `ReadOnlyFileBasedBuffer.get` again.
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
file = self.file
if not skip:
read_pos = file.tell()
res = file.read(numbytes)
if skip:
self.remain -= len(res)
else:
file.seek(read_pos)
return res
```
If `ReadOnlyFileBasedBuffer.get` is called, and the file is not seekable, `file.tell()` or `file.seek(read_pos)` will raise `UnsupportedOperation`.
Wait, when would `ReadOnlyFileBasedBuffer.get` be called?
In `task.py`, I saw that `ReadOnlyFileBasedBuffer` is used and its `prepare()` method is called. If `prepare()` succeeds, then `channel.write_soon(app_iter)` is called.
Let's see what `channel.write_soon` does.
TOOL CALL · run_command
{
"command": "grep -n \"def write_soon\" waitress/channel.py"
}Result of run_command 97 characters
{
"status": "ok",
"stdout": "297: def write_soon(self, data):\n",
"stderr": "",
"exit_code": 0
}Generated tokens 526 tokens · stopped: STOP
`OverflowableBuffer.get` calls `buf.get(numbytes, skip)`.
`buf` can be `BytesIOBasedBuffer` or `TempfileBasedBuffer` (which both inherit from `FileBasedBuffer`).
`FileBasedBuffer.get` uses `tell` and `seek`.
```python
def get(self, numbytes=-1, skip=False):
file = self.file
if not skip:
read_pos = file.tell()
if numbytes < 0:
# Read all
res = file.read()
else:
res = file.read(numbytes)
if skip:
self.remain -= len(res)
else:
file.seek(read_pos)
return res
```
However, `BytesIO` and `TemporaryFile` are always seekable. So `FileBasedBuffer` is fine.
The issue is specifically with `ReadOnlyFileBasedBuffer`, because it takes an arbitrary `file` object in `__init__`.
Let's check `ReadOnlyFileBasedBuffer.get` again.
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
file = self.file
if not skip:
read_pos = file.tell()
res = file.read(numbytes)
if skip:
self.remain -= len(res)
else:
file.seek(read_pos)
return res
```
If `ReadOnlyFileBasedBuffer.get` is called, and the file is not seekable, `file.tell()` or `file.seek(read_pos)` will raise `UnsupportedOperation`.
Wait, when would `ReadOnlyFileBasedBuffer.get` be called?
In `task.py`, I saw that `ReadOnlyFileBasedBuffer` is used and its `prepare()` method is called. If `prepare()` succeeds, then `channel.write_soon(app_iter)` is called.
Let's see what `channel.write_soon` does.<channel|><|tool_call>call:run_command{command:<|"|>grep -n "def write_soon" waitress/channel.py<|"|>}<tool_call|><|tool_response>
Turn 10at 264 s57 tokens out11,812 prompt tokens
Let's read `waitress/channel.py` around line 297.
TOOL CALL · read_file
{
"end_line": 330,
"filepath": "waitress/channel.py",
"start_line": 270
}Result of read_file 2,789 characters
{
"status": "ok",
"filepath": "waitress/channel.py",
"content": " self.connected = False\n self.outbuf_lock.notify()\n wasyncore.dispatcher.close(self)\n\n def add_channel(self, map=None):\n \"\"\"See wasyncore.dispatcher\n\n This hook keeps track of opened channels.\n \"\"\"\n wasyncore.dispatcher.add_channel(self, map)\n self.server.active_channels[self._fileno] = self\n\n def del_channel(self, map=None):\n \"\"\"See wasyncore.dispatcher\n\n This hook keeps track of closed channels.\n \"\"\"\n fd = self._fileno # next line sets this to None\n wasyncore.dispatcher.del_channel(self, map)\n ac = self.server.active_channels\n if fd in ac:\n del ac[fd]\n\n #\n # SYNCHRONOUS METHODS\n #\n\n def write_soon(self, data):\n if not self.connected:\n # if the socket is closed then interrupt the task so that it\n # can cleanup possibly before the app_iter is exhausted\n raise ClientDisconnected\n if data:\n # the async mainloop might be popping data off outbuf; we can\n # block here waiting for it because we're in a task thread\n with self.outbuf_lock:\n self._flush_outbufs_below_high_watermark()\n if not self.connected:\n raise ClientDisconnected\n if data.__class__ is ReadOnlyFileBasedBuffer:\n # they used wsgi.file_wrapper\n self.outbufs.append(data)\n nextbuf = OverflowableBuffer(self.adj.outbuf_overflow)\n self.outbufs.append(nextbuf)\n self.current_outbuf_count = 0\n else:\n if self.current_outbuf_count > self.adj.outbuf_high_watermark:\n # rotate to a new buffer if the current buffer has hit\n # the watermark to avoid it growing unbounded\n nextbuf = OverflowableBuffer(self.adj.outbuf_overflow)\n self.outbufs.append(nextbuf)\n self.current_outbuf_count = 0\n self.outbufs[-1].append(data)\n num_bytes = len(data)\n self.current_outbuf_count += num_bytes\n self.total_outbufs_len += num_bytes\n # XXX We might eventually need to pull the trigger here (to\n # instruct select to stop blocking), but it slows things down so\n # much that I'll hold off for now; \"server push\" on otherwise\n # unbusy systems may suffer.\n return num_bytes",
"start_line": 270,
"end_line": 330,
"total_lines": 415,
"is_truncated": false
}Generated tokens 57 tokens · stopped: STOP
Let's read `waitress/channel.py` around line 297.
<channel|><|tool_call>call:read_file{end_line:330,filepath:<|"|>waitress/channel.py<|"|>,start_line:270}<tool_call|><|tool_response>
Turn 11at 274 s171 tokens out12,608 prompt tokens
In `write_soon`:
```python
if data.__class__ is ReadOnlyFileBasedBuffer:
# they used wsgi.file_wrapper
self.outbufs.append(data)
nextbuf = OverflowableBuffer(self.adj.outbuf_overflow)
self.outbufs.append(nextbuf)
self.current_outbuf_count = 0
```
It appends the `ReadOnlyFileBasedBuffer` object to `self.outbufs`.
Now let's follow where `self.outbufs` is used to send data to the client. It's probably in `_flush_some` or similar.
TOOL CALL · run_command
{
"command": "grep -n \"_flush\" waitress/channel.py"
}Result of run_command 769 characters
{
"status": "ok",
"stdout": "53: close_when_flushed = False # set to True to close the socket when flushed\n107: flush = self._flush_some\n113: flush = self._flush_some_if_lockable\n130: if self.close_when_flushed and not self.total_outbufs_len:\n131: self.close_when_flushed = False\n184: self._flush_some()\n204: def _flush_some_if_lockable(self):\n209: self._flush_some()\n216: def _flush_some(self):\n306: self._flush_outbufs_below_high_watermark()\n333: def _flush_outbufs_below_high_watermark(self):\n389: self.close_when_flushed = True\n402: self._flush_outbufs_below_high_watermark()\n",
"stderr": "",
"exit_code": 0
}Generated tokens 171 tokens · stopped: STOP
In `write_soon`:
```python
if data.__class__ is ReadOnlyFileBasedBuffer:
# they used wsgi.file_wrapper
self.outbufs.append(data)
nextbuf = OverflowableBuffer(self.adj.outbuf_overflow)
self.outbufs.append(nextbuf)
self.current_outbuf_count = 0
```
It appends the `ReadOnlyFileBasedBuffer` object to `self.outbufs`.
Now let's follow where `self.outbufs` is used to send data to the client. It's probably in `_flush_some` or similar.<channel|><|tool_call>call:run_command{command:<|"|>grep -n "_flush" waitress/channel.py<|"|>}<tool_call|><|tool_response>
Turn 12at 277 s48 tokens out13,055 prompt tokens
Let's see `_flush_some`.
TOOL CALL · read_file
{
"end_line": 230,
"filepath": "waitress/channel.py",
"start_line": 216
}Result of read_file 660 characters
{
"status": "ok",
"filepath": "waitress/channel.py",
"content": " def _flush_some(self):\n # Send as much data as possible to our client\n\n sent = 0\n dobreak = False\n\n while True:\n outbuf = self.outbufs[0]\n # use outbuf.__len__ rather than len(outbuf) FBO of not getting\n # OverflowError on 32-bit Python\n outbuflen = outbuf.__len__()\n while outbuflen > 0:\n chunk = outbuf.get(self.sendbuf_len)\n num_sent = self.send(chunk)\n if num_sent:",
"start_line": 216,
"end_line": 230,
"total_lines": 415,
"is_truncated": false
}Generated tokens 48 tokens · stopped: STOP
Let's see `_flush_some`.
<channel|><|tool_call>call:read_file{end_line:230,filepath:<|"|>waitress/channel.py<|"|>,start_line:216}<tool_call|><|tool_response>
Turn 13at 337 s1,067 tokens out13,328 prompt tokens
Yes, `chunk = outbuf.get(self.sendbuf_len)` is called.
If `outbuf` is a `ReadOnlyFileBasedBuffer`, this calls `ReadOnlyFileBasedBuffer.get`.
As analyzed before, `ReadOnlyFileBasedBuffer.get` calls `tell()` and `seek()`.
So if `prepare()` was successful, `get()` will be called and it should work.
But if `prepare()` was called and ` UnsupportedOperation` was not caught, the server crashes during `prepare()`.
If we catch `UnsupportedOperation` in `prepare()`, then `self.remain` remains 0.
And then `get()` is called.
If `self.remain` is 0:
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
```
`numbytes` becomes 0.
Then:
```python
if not skip:
read_pos = file.tell()
```
CRASH! Because `file.tell()` raises `UnsupportedOperation`.
So we MUST fix `get` as well, OR we must ensure that `get` is not called if the file is not seekable.
But wait, if the file is not seekable, we should have just let the `task` iterate over the `ReadOnlyFileBasedBuffer` instead of adding it to `outbufs`.
In `task.py`:
```python
if app_iter.__class__ is ReadOnlyFileBasedBuffer:
cl = self.content_length
size = app_iter.prepare(cl)
if size:
# ...
self.channel.write_soon(app_iter)
can_close_app_iter = False
return
```
If `prepare()` returns 0, it doesn't call `write_soon(app_iter)` and instead iterates over `app_iter`.
This is what we want for non-seekable files.
So, the fix in `prepare()` to catch `UnsupportedOperation` and return 0 (or `self.remain` which is 0) is sufficient, because then `write_soon` won't be called, and `get()` won't be called.
Wait, if `size` is provided to `prepare(size)`, and `fsize` is determined, then `self.remain = min(fsize, size)`.
If `prepare()` fails to determine `fsize`, it returns `self.remain` (which is 0).
Then `if size:` in `task.py` will be false, and it will iterate.
So the only thing is to make sure `prepare()` doesn't crash.
Let's double check `ReadOnlyFileBasedBuffer.prepare` again.
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
return self.remain
```
If `hasattr(self.file, 'seek') and hasattr(self.file, 'tell')` is true, but they raise `UnsupportedOperation`, then we should catch it and return 0.
Wait, should we also check `seekable()`?
If we check `seekable()`, we might avoid the `try...except`.
```python
def prepare(self, size=None):
if getattr(self.file, 'seekable', lambda: False)():
#...
```
But wait, some objects might have `seekable()` return `True` but still raise `UnsupportedOperation` (unlikely but possible).
And some objects might NOT have `seekable()` but DO support `seek`/`tell`.
The safest thing is:
1. Check `hasattr(self.file, 'seek') and hasattr(self.file, 'tell')`.
2. Try the `seek`/`tell` dance.
3. Catch `(io.UnsupportedOperation, AttributeError)`.
Wait, I need to make sure `io` is available.
Let's see how other parts of `waitress` handle `UnsupportedOperation`.
I'll search for `UnsupportedOperation` in the whole repository.
TOOL CALL · run_command
{
"command": "grep -rn \"UnsupportedOperation\" waitress/"
}Result of run_command 127 characters
{
"status": "error",
"error_type": "CommandError",
"error_message": "",
"details": {
"stdout": "",
"stderr": "",
"exit_code": 1
}
}Generated tokens 1,067 tokens · stopped: STOP
Yes, `chunk = outbuf.get(self.sendbuf_len)` is called.
If `outbuf` is a `ReadOnlyFileBasedBuffer`, this calls `ReadOnlyFileBasedBuffer.get`.
As analyzed before, `ReadOnlyFileBasedBuffer.get` calls `tell()` and `seek()`.
So if `prepare()` was successful, `get()` will be called and it should work.
But if `prepare()` was called and ` UnsupportedOperation` was not caught, the server crashes during `prepare()`.
If we catch `UnsupportedOperation` in `prepare()`, then `self.remain` remains 0.
And then `get()` is called.
If `self.remain` is 0:
```python
def get(self, numbytes=-1, skip=False):
# never read more than self.remain (it can be user-specified)
if numbytes == -1 or numbytes > self.remain:
numbytes = self.remain
```
`numbytes` becomes 0.
Then:
```python
if not skip:
read_pos = file.tell()
```
CRASH! Because `file.tell()` raises `UnsupportedOperation`.
So we MUST fix `get` as well, OR we must ensure that `get` is not called if the file is not seekable.
But wait, if the file is not seekable, we should have just let the `task` iterate over the `ReadOnlyFileBasedBuffer` instead of adding it to `outbufs`.
In `task.py`:
```python
if app_iter.__class__ is ReadOnlyFileBasedBuffer:
cl = self.content_length
size = app_iter.prepare(cl)
if size:
# ...
self.channel.write_soon(app_iter)
can_close_app_iter = False
return
```
If `prepare()` returns 0, it doesn't call `write_soon(app_iter)` and instead iterates over `app_iter`.
This is what we want for non-seekable files.
So, the fix in `prepare()` to catch `UnsupportedOperation` and return 0 (or `self.remain` which is 0) is sufficient, because then `write_soon` won't be called, and `get()` won't be called.
Wait, if `size` is provided to `prepare(size)`, and `fsize` is determined, then `self.remain = min(fsize, size)`.
If `prepare()` fails to determine `fsize`, it returns `self.remain` (which is 0).
Then `if size:` in `task.py` will be false, and it will iterate.
So the only thing is to make sure `prepare()` doesn't crash.
Let's double check `ReadOnlyFileBasedBuffer.prepare` again.
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
return self.remain
```
If `hasattr(self.file, 'seek') and hasattr(self.file, 'tell')` is true, but they raise `UnsupportedOperation`, then we should catch it and return 0.
Wait, should we also check `seekable()`?
If we check `seekable()`, we might avoid the `try...except`.
```python
def prepare(self, size=None):
if getattr(self.file, 'seekable', lambda: False)():
#...
```
But wait, some objects might have `seekable()` return `True` but still raise `UnsupportedOperation` (unlikely but possible).
And some objects might NOT have `seekable()` but DO support `seek`/`tell`.
The safest thing is:
1. Check `hasattr(self.file, 'seek') and hasattr(self.file, 'tell')`.
2. Try the `seek`/`tell` dance.
3. Catch `(io.UnsupportedOperation, AttributeError)`.
Wait, I need to make sure `io` is available.
Let's see how other parts of `waitress` handle `UnsupportedOperation`.
I'll search for `UnsupportedOperation` in the whole repository.
<channel|><|tool_call>call:run_command{command:<|"|>grep -rn "UnsupportedOperation" waitress/<|"|>}<tool_call|><|tool_response>
Turn 14at 403 s1,051 tokens out14,450 prompt tokens
It's not used anywhere in `waitress/`.
Let's check if we can just use a `try...except Exception as e:` but that's too broad.
Since `io.UnsupportedOperation` is the specific exception mentioned in the problem statement, I'll use it.
Wait, if I import `io`, I can use `io.UnsupportedOperation`.
Let's modify `waitress/buffers.py`. I'll add `import io` (or just `from io import UnsupportedOperation`) at the top.
Wait, `waitress/buffers.py` already has `from io import BytesIO`. I can change it to `from io import BytesIO, UnsupportedOperation`.
Let's check if `UnsupportedOperation` exists in `io` for all supported Python versions. Yes, it's been there since Python 2.6.
Wait, one more thing. What if `self.file.tell()` works but `self.file.seek()` fails? The `try...except` will handle it.
Let's verify my proposed change in `ReadOnlyFileBasedBuffer.prepare`.
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
try:
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
except (UnsupportedOperation, AttributeError):
pass
return self.remain
```
Wait, if I use `from io import BytesIO, UnsupportedOperation`, then I can use `UnsupportedOperation`.
Let's refine the plan.
1. Modify `waitress/buffers.py` to import `UnsupportedOperation`.
2. Modify `ReadOnlyFileBasedBuffer.prepare` to wrap the `seek`/`tell` logic in `try...except (UnsupportedOperation, AttributeError)`. (AttributeError just in case).
Actually, if `hasattr` is checked, `AttributeError` is unlikely, but `UnsupportedOperation` is what we are looking for.
Wait, should I also fix `ReadOnlyFileBasedBuffer.get`?
As I concluded, `get` is only called if `prepare` returned a non-zero `self.remain`.
If `prepare` catches `UnsupportedOperation` and doesn't set `self.remain` (so it stays 0), then `task.py` will not call `write_soon(app_iter)`, and thus `get` will not be called.
Is it possible that `prepare` is called, returns a non-zero value, but then `get` is called and it fails?
Yes, if `prepare` succeeded (meaning `seek` and `tell` worked at that time), but then something changed. But that's unlikely for a file.
Or if `prepare` succeeded but only used `tell` and `seek(0, 2)`, and then `get` is called and calls `tell()` again. But if it worked in `prepare`, it should work in `get`.
Wait, if `prepare` is NOT called at all?
In `task.py`, `prepare` is always called if `app_iter` is a `ReadOnlyFileBasedBuffer`.
```python
if app_iter.__class__ is ReadOnlyFileBasedBuffer:
cl = self.content_length
size = app_iter.prepare(cl)
if size:
# ...
self.channel.write_soon(app_iter)
can_close_app_iter = False
return
```
So if `prepare` returns 0, `get` is never called.
What if the file is empty? `fsize` will be 0. `prepare` will return 0.
Then it will go to the iterator. The iterator will read and find no data, then stop. This is correct.
So the only fix needed is in `prepare`.
Let's double check the problem statement:
"In `io.IOBase` subclasses that are not seekable, those two methods exist but raise an `UnsupportedOperation`, in case of io.IOBase instance `.seekable` should probably be checked for `True` or the `UnsupportedOperation` should be trapped."
My proposed fix traps `UnsupportedOperation`.
Let's implement it.
First, I'll check the imports again.
TOOL CALL · read_file
{
"end_line": 20,
"filepath": "waitress/buffers.py",
"start_line": 1
}Result of read_file 952 characters
{
"status": "ok",
"filepath": "waitress/buffers.py",
"content": "##############################################################################\n#\n# Copyright (c) 2001-2004 Zope Foundation and Contributors.\n# All Rights Reserved.\n#\n# This software is subject to the provisions of the Zope Public License,\n# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.\n# THIS SOFTWARE IS PROVIDED \"AS IS\" AND ANY AND ALL EXPRESS OR IMPLIED\n# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED\n# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS\n# FOR A PARTICULAR PURPOSE.\n#\n##############################################################################\n\"\"\"Buffers\n\"\"\"\nfrom io import BytesIO\n\n# copy_bytes controls the size of temp. strings for shuffling data around.\nCOPY_BYTES = 1 << 18 # 256K\n",
"start_line": 1,
"end_line": 20,
"total_lines": 298,
"is_truncated": false
}Generated tokens 1,051 tokens · stopped: STOP
It's not used anywhere in `waitress/`.
Let's check if we can just use a `try...except Exception as e:` but that's too broad.
Since `io.UnsupportedOperation` is the specific exception mentioned in the problem statement, I'll use it.
Wait, if I import `io`, I can use `io.UnsupportedOperation`.
Let's modify `waitress/buffers.py`. I'll add `import io` (or just `from io import UnsupportedOperation`) at the top.
Wait, `waitress/buffers.py` already has `from io import BytesIO`. I can change it to `from io import BytesIO, UnsupportedOperation`.
Let's check if `UnsupportedOperation` exists in `io` for all supported Python versions. Yes, it's been there since Python 2.6.
Wait, one more thing. What if `self.file.tell()` works but `self.file.seek()` fails? The `try...except` will handle it.
Let's verify my proposed change in `ReadOnlyFileBasedBuffer.prepare`.
```python
def prepare(self, size=None):
if hasattr(self.file, 'seek') and hasattr(self.file, 'tell'):
try:
start_pos = self.file.tell()
self.file.seek(0, 2)
end_pos = self.file.tell()
self.file.seek(start_pos)
fsize = end_pos - start_pos
if size is None:
self.remain = fsize
else:
self.remain = min(fsize, size)
except (UnsupportedOperation, AttributeError):
pass
return self.remain
```
Wait, if I use `from io import BytesIO, UnsupportedOperation`, then I can use `UnsupportedOperation`.
Let's refine the plan.
1. Modify `waitress/buffers.py` to import `UnsupportedOperation`.
2. Modify `ReadOnlyFileBasedBuffer.prepare` to wrap the `seek`/`tell` logic in `try...except (UnsupportedOperation, AttributeError)`. (AttributeError just in case).
Actually, if `hasattr` is checked, `AttributeError` is unlikely, but `UnsupportedOperation` is what we are looking for.
Wait, should I also fix `ReadOnlyFileBasedBuffer.get`?
As I concluded, `get` is only called if `prepare` returned a non-zero `self.remain`.
If `prepare` catches `UnsupportedOperation` and doesn't set `self.remain` (so it stays 0), then `task.py` will not call `write_soon(app_iter)`, and thus `get` will not be called.
Is it possible that `prepare` is called, returns a non-zero value, but then `get` is called and it fails?
Yes, if `prepare` succeeded (meaning `seek` and `tell` worked at that time), but then something changed. But that's unlikely for a file.
Or if `prepare` succeeded but only used `tell` and `seek(0, 2)`, and then `get` is called and calls `tell()` again. But if it worked in `prepare`, it should work in `get`.
Wait, if `prepare` is NOT called at all?
In `task.py`, `prepare` is always called if `app_iter` is a `ReadOnlyFileBasedBuffer`.
```python
if app_iter.__class__ is ReadOnlyFileBasedBuffer:
cl = self.content_length
size = app_iter.prepare(cl)
if size:
# ...
self.channel.write_soon(app_iter)
can_close_app_iter = False
return
```
So if `prepare` returns 0, `get` is never called.
What if the file is empty? `fsize` will be 0. `prepare` will return 0.
Then it will go to the iterator. The iterator will read and find no data, then stop. This is correct.
So the only fix needed is in `prepare`.
Let's double check the problem statement:
"In `io.IOBase` subclasses that are not seekable, those two methods exist but raise an `UnsupportedOperation`, in case of io.IOBase instance `.seekable` should probably be checked for `True` or the `UnsupportedOperation` should be trapped."
My proposed fix traps `UnsupportedOperation`.
Let's implement it.
First, I'll check the imports again.
<channel|><|tool_call>call:read_file{end_line:20,filepath:<|"|>waitress/buffers.py<|"|>,start_line:1}<tool_call|><|tool_response>
Patch, tests and logs
Final code change Included
Test output Missing
Not saved for this rollout. Nothing has been inferred or reconstructed.
Test errors Missing
Not saved for this rollout. Nothing has been inferred or reconstructed.
Test report (JUnit) Missing
Not saved for this rollout. Nothing has been inferred or reconstructed.
Agent log Included
[ 0.0s] 📋 System Prompt: You are a principal Python software engineer resolving a repository issue in `/workspace`.
[ 0.0s] 🎯 Task Prompt: You are evaluating a software engineering task for repository Pylons/waitress.
[ 17.8s] 💭 (872 chars) "The user is reporting a bug in `ReadOnlyFileBasedBuffer` in `waitress/buffers.py`.
The issue is that it checks for the p..."
[ 17.8s] 📖 read_file (waitress/buffers.py)
[ 17.8s] ✓ {'status': 'ok', 'filepath': 'waitress/buffers.py', 'content': ' nf.write(data)\n
self.file = nf\n\n …
[ 63.2s] 💭 (1482 chars) "The code in `ReadOnlyFileBasedBuffer.prepare` (lines 140-149):
```python
def prepare(self, size=None):
if h..."
[ 63.2s] 🔧 run_command (22 lines) python3 - <<'PY'
[ 63.3s] → Caught expected UnsupportedOperation
[ 74.5s] 💭 (275 chars) "Okay, the reproduction confirmed that it raises `io.UnsupportedOperation`.
Now let's check if we can use `seekable()`. ..."
[ 74.5s] 🔧 run_command (23 lines) python3 - <<'PY'
[ 74.5s] → seekable: False
[ 108.7s] 💭 (2007 chars) "The issue is that `ReadOnlyFileBasedBuffer.prepare` only checks for the presence of the
methods, not whether they are ac..."
[ 108.7s] 📖 read_file (waitress/buffers.py)
[ 108.7s] ✓ {'status': 'ok', 'filepath': 'waitress/buffers.py', 'content':
'########################################################…
[ 141.5s] 💭 (1637 chars) "`FileBasedBuffer` defines `remain = 0` as a class attribute.
So in `ReadOnlyFileBasedBuffer.prepare`:
```python
def..."
[ 141.5s] 🔧 run_command grep -rn "ReadOnlyFileBasedBuffer" waitress/task.py
[ 141.5s] → 21:from .buffers import ReadOnlyFileBasedBuffer
[ 145.1s] 💭 (45 chars) "Let's see `waitress/task.py` around line 451."
[ 145.1s] 📖 read_file (waitress/task.py)
[ 145.1s] ✓ {'status': 'ok', 'filepath': 'waitress/task.py', 'content': ' raise
ValueError("carriage return/line …
[ 223.1s] 💭 (3944 chars) "Yes, in `task.py`:
```python
if app_iter.__class__ is ReadOnlyFileBasedBuffer:
cl = self.con..."
[ 223.1s] 🔧 run_command grep -rn "\.get(" waitress/
[ 223.1s] → waitress/parser.py:210: connection = headers.get('CONNECTION', '')
[ 230.4s] 💭 (171 chars) "`waitress/channel.py:228` calls `outbuf.get(self.sendbuf_len)`.
`outbuf` is likely an `OverflowableBuffer`.
Let's check..."
[ 230.4s] 📖 read_file (waitress/buffers.py)
[ 230.5s] ✓ {'status': 'ok', 'filepath': 'waitress/buffers.py', 'content': ' return\n buf
= self._create_b…
[ 260.2s] 💭 (1725 chars) "`OverflowableBuffer.get` calls `buf.get(numbytes, skip)`.
`buf` can be `BytesIOBasedBuffer` or `TempfileBasedBuffer` (wh..."
[ 260.2s] 🔧 run_command grep -n "def write_soon" waitress/channel.py
[ 260.3s] → 297: def write_soon(self, data):
[ 263.5s] 💭 (49 chars) "Let's read `waitress/channel.py` around line 297."
[ 263.5s] 📖 read_file (waitress/channel.py)
[ 263.6s] ✓ {'status': 'ok', 'filepath': 'waitress/channel.py', 'content': ' self.connected = False\n
self.out…
[ 273.8s] 💭 (546 chars) "In `write_soon`:
```python
if data.__class__ is ReadOnlyFileBasedBuffer:
# they used..."
[ 273.8s] 🔧 run_command grep -n "_flush" waitress/channel.py
[ 273.9s] → 53: close_when_flushed = False # set to True to close the socket when flushed
[ 276.3s] 💭 (24 chars) "Let's see `_flush_some`."
[ 276.3s] 📖 read_file (waitress/channel.py)
[ 276.4s] ✓ {'status': 'ok', 'filepath': 'waitress/channel.py', 'content': ' def _flush_some(self):\n #
Send as much data …
[ 336.6s] 💭 (3657 chars) "Yes, `chunk = outbuf.get(self.sendbuf_len)` is called.
If `outbuf` is a `ReadOnlyFileBasedBuffer`, this calls `ReadOnlyF..."
[ 336.6s] 🔧 run_command grep -rn "UnsupportedOperation" waitress/
[ 336.7s] → error (exit 0):
[ 402.1s] 💭 (3807 chars) "It's not used anywhere in `waitress/`.
Let's check if we can just use a `try...except Exception as e:` but that's too b..."
[ 402.1s] 📖 read_file (waitress/buffers.py)
[ 402.1s] ✓ {'status': 'ok', 'filepath': 'waitress/buffers.py', 'content':
'########################################################…
Native result row
{
"agent_error": "Agent exceeded session timeout (7.5 min)",
"duration_seconds": 452.74,
"error": "Empty agent patch",
"grade": {
"error": "Empty agent patch",
"resolved": false,
"strict_clean_patch": false,
"test_exit_code": -1
},
"instance_id": "pylons__waitress-249",
"pass_idx": 0,
"patch_chars": 0,
"phase1_seconds": 452.74,
"repo": "Pylons/waitress",
"request_log_path": "/kaggle-root/working/r31/rollouts_X/requests/pylons__waitress-249__p0__r0.jsonl",
"resolved": false,
"rollout_idx": 0,
"run_key": "pylons__waitress-249__p0__r0",
"strict_clean_patch": false,
"tool_calls": 14,
"total_llm_calls": 14,
"trace_path": "/kaggle-root/working/r31/rollouts_X/traces/trace_pylons__waitress-249__p0__r0.json"
}