Leaderboard  /  django-10999

django__django-10999

django/django · v3.0  ·  5 steps · 13,104 tokens · 22s
partial
0.917

The task

The bug report the agent was given — plus the gold fix and hidden tests, shown here for reference. The agent saw only the problem statement.

Problem statementgithub issue
Fix parse_duration() for some negative durations
Description
	
The ​https://docs.djangoproject.com/en/2.1/_modules/django/utils/dateparse/ defines:
standard_duration_re = re.compile(
	r'^'
	r'(?:(?P<days>-?\d+) (days?, )?)?'
	r'((?:(?P<hours>-?\d+):)(?=\d+:\d+))?'
	r'(?:(?P<minutes>-?\d+):)?'
	r'(?P<seconds>-?\d+)'
	r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?'
	r'$'
)
that doesn't match to negative durations, because of the <hours> definition final (lookahead) part does not have '-?' in it. The following will work:
	r'((?:(?P<hours>-?\d+):)(?=-?\d+:-?\d+))?'
(Thanks to Konstantin Senichev for finding the fix.)
Gold patchheld back · the reference fix
diff --git a/django/utils/dateparse.py b/django/utils/dateparse.py--- a/django/utils/dateparse.py+++ b/django/utils/dateparse.py@@ -29,9 +29,10 @@ standard_duration_re = re.compile( r'^' r'(?:(?P<days>-?\d+) (days?, )?)?'- r'((?:(?P<hours>-?\d+):)(?=\d+:\d+))?'- r'(?:(?P<minutes>-?\d+):)?'- r'(?P<seconds>-?\d+)'+ r'(?P<sign>-?)'+ r'((?:(?P<hours>\d+):)(?=\d+:\d+))?'+ r'(?:(?P<minutes>\d+):)?'+ r'(?P<seconds>\d+)' r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?' r'$' )
Hidden testtest_patch · applied only to grade
diff --git a/tests/utils_tests/test_dateparse.py b/tests/utils_tests/test_dateparse.py--- a/tests/utils_tests/test_dateparse.py+++ b/tests/utils_tests/test_dateparse.py@@ -113,9 +113,12 @@ def test_negative(self): test_values = ( ('-4 15:30', timedelta(days=-4, minutes=15, seconds=30)), ('-172800', timedelta(days=-2)),- ('-15:30', timedelta(minutes=-15, seconds=30)),- ('-1:15:30', timedelta(hours=-1, minutes=15, seconds=30)),+ ('-15:30', timedelta(minutes=-15, seconds=-30)),+ ('-1:15:30', timedelta(hours=-1, minutes=-15, seconds=-30)), ('-30.1', timedelta(seconds=-30, milliseconds=-100)),+ ('-00:01:01', timedelta(minutes=-1, seconds=-1)),+ ('-01:01', timedelta(seconds=-61)),+ ('-01:-01', None), ) for source, expected in test_values: with self.subTest(source=source):
1FAIL → PASS (of 2)
10PASS → PASS
11 / 12graded tests

The agent run

The agent's step-by-step attempt — its reasoning, the tools it called, and the patch it produced.

System promptharness.agent.build_system_prompt
You are an AI coding assistant working inside a code repository that contains a bug. Investigate the code, find the bug, and fix it.

Your working directory is: /testbed
All four tools (read_file, write_file, edit_file, run_bash) already run from that directory. Use plain relative paths; do not prefix shell commands with cd. Fix the bug by editing source files only; do not create or edit test files.
Step 01 tool use
Let me understand the issue. The bug is in the `standard_duration_re` regex pattern in `/testbed/django/utils/dateparse.py`. The lookahead `(?=\d+:\d+)` doesn't account for negative numbers, so it fails to match negative durations. The fix is to change the lookahead to `(?=-?\d+:-?\d+)`. Let me first read the file to see the current state.
read_file{ path: "/testbed/django/utils/dateparse.py" }
tool result · read_file
"""Functions to parse datetime objects.""" # We're using regular expressions rather than time.strptime because: # - They provide both validation and parsing. # - They're more flexible for datetimes. # - The date/datetime/time constructors produce friendlier error messages. import datetime import re from django.utils.timezone import get_fixed_timezone, utc date_re = re.compile( r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})$' ) time_re = re.compile( r'(?P<h …
Step 02 tool use
Now I can see the bug. The lookahead in `standard_duration_re` is `(?=\d+:\d+)` but it should be `(?=-?\d+:-?\d+)` to also match negative durations. Let me fix it.
The bug is in the lookahead of `standard_duration_re`. The pattern `(?=\d+:\d+)` only matches positive digits, so negative duration strings like `-1:00:00` fail to match because the lookahead doesn't allow for a leading `-` sign.
edit_file{ path: "/testbed/django/utils/dateparse.py", old_string: " r'((?:(?P<hours>-?\\d+):)(?=\\d+:\\d+))?'", new_string: " r'((?:(?P<hours>-?\\d+):)(?=-?\\d+:-?\\d+))?'" }
tool result · edit_file
File /testbed/django/utils/dateparse.py edited successfully.
Step 03 tool use
Let me verify the fix looks correct.
Let me verify the fix looks correct:
read_file{ path: "/testbed/django/utils/dateparse.py", offset: "33", limit: "10" }
tool result · read_file
ERROR: bad arguments for 'read_file': Toolbox.read_file() got an unexpected keyword argument 'offset'
Step 04 tool use
Let me just read the file again and check the right line.
run_bash{ command: "sed -n '34,42p' /testbed/django/utils/dateparse.py" }
tool result · run_bash
exitcode: 0 stdout: r'(?P<seconds>-?\d+)' r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?' r'$' ) # Support the sections of ISO 8601 date representation that are accepted by # timedelta iso8601_duration_re = re.compile( r'^(?P<sign>[-+]?)' stderr:
Step 05 reasoning
The edit was successful. The fix changes the lookahead from `(?=\d+:\d+)` to `(?=-?\d+:-?\d+)` so that negative hours, minutes, and seconds are properly matched in the standard duration regex.
The fix is applied. The lookahead `(?=\d+:\d+)` has been changed to `(?=-?\d+:-?\d+)` on line 30 of `/testbed/django/utils/dateparse.py`. Now negative duration strings like `-1:00:00` or `-1:-30:-45` will correctly match the `standard_duration_re` pattern, since the lookahead properly accounts for optional negative signs on both the minutes and seconds portions.
Agent diffcaptured before grading
diff --git a/django/utils/dateparse.py b/django/utils/dateparse.pyindex 8d08b7d1d3..a037758784 100644--- a/django/utils/dateparse.py+++ b/django/utils/dateparse.py@@ -29,7 +29,7 @@ datetime_re = re.compile( standard_duration_re = re.compile( r'^' r'(?:(?P<days>-?\d+) (days?, )?)?'- r'((?:(?P<hours>-?\d+):)(?=\d+:\d+))?'+ r'((?:(?P<hours>-?\d+):)(?=-?\d+:-?\d+))?' r'(?:(?P<minutes>-?\d+):)?' r'(?P<seconds>-?\d+)' r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?'