FAILURE MAP
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FA-9351 / Dependency resolution / Open access

Release candidate selection: The oldest compatible version wins · case 01

The oldest compatible version wins.

Verified by executionVariant 1 · 18 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The implementation substitutes return min((r['version'] for r in items), default=None) for return max((r['version'] for r in items), default=None), so the oldest compatible version wins.

THE FAILURE

The implementation substitutes return min((r['version'] for r in items), default=None) for return max((r['version'] for r in items), default=None), so the oldest compatible version wins.

Unsuccessful approach: The attempted repair substitutes return next((r['version'] for r in items), None). Fixture 7 still yields (1, 0) instead of (2, 0).

Case contract

Choose the greatest compatible version; exclude yanked, prerelease, wrong-platform and below-minimum candidates. Return None if no candidates remain. Versions are integer tuples.

Why this case matters

An offline model of release candidate selection, suitable for testing build and release tooling without external services.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(releases, minimum, platform):
    items = [r for r in releases if not r['yanked']]
    items = [r for r in items if not r['pre']]
    items = [r for r in items if r['platform'] in [platform, 'any']]
    items = [r for r in items if r['version'] >= minimum]
    return min((r['version'] for r in items), default=None)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve([], (0, 0), 'linux'), None)
check('fixture 2', solve([], (0, 0), 'win'), None)
check('fixture 3', solve([], (2, 0), 'linux'), None)
check('fixture 4', solve([], (2, 0), 'win'), None)
check('fixture 5', solve([], (6, 0), 'linux'), None)
check('fixture 6', solve([], (6, 0), 'win'), None)
check('fixture 7', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (0, 0), 'linux'), (2, 0))
check('fixture 8', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (0, 0), 'win'), (5, 0))
check('fixture 9', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (2, 0), 'linux'), (2, 0))
check('fixture 10', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (2, 0), 'win'), (5, 0))
check('fixture 11', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (6, 0), 'linux'), None)
check('fixture 12', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (6, 0), 'win'), None)
check('fixture 13', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (0, 0), 'linux'), (2, 0))
check('fixture 14', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (0, 0), 'win'), (2, 0))
check('fixture 15', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (2, 0), 'linux'), (2, 0))
check('fixture 16', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (2, 0), 'win'), (2, 0))
check('fixture 17', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (6, 0), 'linux'), None)
check('fixture 18', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (6, 0), 'win'), None)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
fixture 1NoneNonePassed
fixture 2NoneNonePassed
fixture 3NoneNonePassed
fixture 4NoneNonePassed
fixture 5NoneNonePassed
fixture 6NoneNonePassed
fixture 7[1, 0][2, 0]Failed
fixture 8[1, 0][5, 0]Failed
fixture 9[2, 0][2, 0]Passed
fixture 10[5, 0][5, 0]Passed
fixture 11NoneNonePassed
fixture 12NoneNonePassed
fixture 13[2, 0][2, 0]Passed
fixture 14[2, 0][2, 0]Passed
fixture 15[2, 0][2, 0]Passed
fixture 16[2, 0][2, 0]Passed
fixture 17NoneNonePassed
fixture 18NoneNonePassed

SHA-256 / 330edd6498460142df668bfa8185b013db18c707f7bbc2cef3131f5f8d460150

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(releases, minimum, platform):
    items = [r for r in releases if not r['yanked']]
    items = [r for r in items if not r['pre']]
    items = [r for r in items if r['platform'] in [platform, 'any']]
    items = [r for r in items if r['version'] >= minimum]
    return next((r['version'] for r in items), None)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve([], (0, 0), 'linux'), None)
check('fixture 2', solve([], (0, 0), 'win'), None)
check('fixture 3', solve([], (2, 0), 'linux'), None)
check('fixture 4', solve([], (2, 0), 'win'), None)
check('fixture 5', solve([], (6, 0), 'linux'), None)
check('fixture 6', solve([], (6, 0), 'win'), None)
check('fixture 7', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (0, 0), 'linux'), (2, 0))
check('fixture 8', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (0, 0), 'win'), (5, 0))
check('fixture 9', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (2, 0), 'linux'), (2, 0))
check('fixture 10', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (2, 0), 'win'), (5, 0))
check('fixture 11', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (6, 0), 'linux'), None)
check('fixture 12', solve([{'version': (1, 0), 'yanked': False, 'pre': False, 'platform': 'any'}, {'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'linux'}, {'version': (3, 0), 'yanked': True, 'pre': False, 'platform': 'linux'}, {'version': (4, 0), 'yanked': False, 'pre': True, 'platform': 'linux'}, {'version': (5, 0), 'yanked': False, 'pre': False, 'platform': 'win'}], (6, 0), 'win'), None)
check('fixture 13', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (0, 0), 'linux'), (2, 0))
check('fixture 14', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (0, 0), 'win'), (2, 0))
check('fixture 15', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (2, 0), 'linux'), (2, 0))
check('fixture 16', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (2, 0), 'win'), (2, 0))
check('fixture 17', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (6, 0), 'linux'), None)
check('fixture 18', solve([{'version': (2, 0), 'yanked': False, 'pre': False, 'platform': 'any'}], (6, 0), 'win'), None)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
fixture 1NoneNonePassed
fixture 2NoneNonePassed
fixture 3NoneNonePassed
fixture 4NoneNonePassed
fixture 5NoneNonePassed
fixture 6NoneNonePassed
fixture 7[1, 0][2, 0]Failed
fixture 8[1, 0][5, 0]Failed
fixture 9[2, 0][2, 0]Passed
fixture 10[5, 0][5, 0]Passed
fixture 11NoneNonePassed
fixture 12NoneNonePassed
fixture 13[2, 0][2, 0]Passed
fixture 14[2, 0][2, 0]Passed
fixture 15[2, 0][2, 0]Passed
fixture 16[2, 0][2, 0]Passed
fixture 17NoneNonePassed
fixture 18NoneNonePassed

SHA-256 / f450c02aec80eecaf82923f0bd2ba53d96c8b3989cfa258104931837fdd282a2

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 18 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:29.197649+00:00.

Case digest / bbf477fdbffb022e29b0e18bff0444f140ab02fa19a8ae7de8b523bffdbf8c44