FA-9461 / Dependency resolution / Open access
Peer dependency diagnostics: Missing peers are classified as version failures · case 01
Missing peers are classified as version failures.
ROOT CAUSE
The implementation substitutes (name, 'low') for (name, 'missing'), so missing peers are classified as version failures.
VERIFIED REPAIR
Distinguish absent installations from incompatible installed versions.
Unsuccessful approach: The attempted repair substitutes (name, 'high'). Fixture 2 still yields [('a', 'high')] instead of [('a', 'missing')].
Case contract
For each peer in declaration order, ignore missing optional peers, report missing required peers, report too-old installed peers, report too-new peers, and accept inclusive lower/exclusive upper versions.
Why this case matters
An offline model of peer dependency diagnostics, 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(peers, installed):
result = []
for name, low, high, optional in peers:
if name not in installed:
if not optional: result.append((name, 'low'))
continue
version = installed[name]
if version < low: result.append((name, 'low'))
elif version >= high: result.append((name, 'high'))
return result
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve([], {}), [])
check('fixture 2', solve([('a', 1, 3, False)], {}), [('a', 'missing')])
check('fixture 3', solve([('a', 1, 3, True)], {}), [])
check('fixture 4', solve([('a', 1, 3, False)], {'a': 0}), [('a', 'low')])
check('fixture 5', solve([('a', 1, 3, False)], {'a': 1}), [])
check('fixture 6', solve([('a', 1, 3, False)], {'a': 2}), [])
check('fixture 7', solve([('a', 1, 3, False)], {'a': 3}), [('a', 'high')])
check('fixture 8', solve([('a', 1, 3, False)], {'a': 4}), [('a', 'high')])
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | [] | [] | Passed |
| fixture 2 | [['a', 'low']] | [['a', 'missing']] | Failed |
| fixture 3 | [] | [] | Passed |
| fixture 4 | [['a', 'low']] | [['a', 'low']] | Passed |
| fixture 5 | [] | [] | Passed |
| fixture 6 | [] | [] | Passed |
| fixture 7 | [['a', 'high']] | [['a', 'high']] | Passed |
| fixture 8 | [['a', 'high']] | [['a', 'high']] | Passed |
SHA-256 / 8f2418054e8ed6552a241ba596eecab5525224e4fa021cb80be038311a8eb474
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(peers, installed):
result = []
for name, low, high, optional in peers:
if name not in installed:
if not optional: result.append((name, 'high'))
continue
version = installed[name]
if version < low: result.append((name, 'low'))
elif version >= high: result.append((name, 'high'))
return result
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve([], {}), [])
check('fixture 2', solve([('a', 1, 3, False)], {}), [('a', 'missing')])
check('fixture 3', solve([('a', 1, 3, True)], {}), [])
check('fixture 4', solve([('a', 1, 3, False)], {'a': 0}), [('a', 'low')])
check('fixture 5', solve([('a', 1, 3, False)], {'a': 1}), [])
check('fixture 6', solve([('a', 1, 3, False)], {'a': 2}), [])
check('fixture 7', solve([('a', 1, 3, False)], {'a': 3}), [('a', 'high')])
check('fixture 8', solve([('a', 1, 3, False)], {'a': 4}), [('a', 'high')])
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | [] | [] | Passed |
| fixture 2 | [['a', 'high']] | [['a', 'missing']] | Failed |
| fixture 3 | [] | [] | Passed |
| fixture 4 | [['a', 'low']] | [['a', 'low']] | Passed |
| fixture 5 | [] | [] | Passed |
| fixture 6 | [] | [] | Passed |
| fixture 7 | [['a', 'high']] | [['a', 'high']] | Passed |
| fixture 8 | [['a', 'high']] | [['a', 'high']] | Passed |
SHA-256 / 53dbe0541df1fe84a4fe99a751ea52983cd232cca6687b61bf93baba02c1dfa1
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(peers, installed):
result = []
for name, low, high, optional in peers:
if name not in installed:
if not optional: result.append((name, 'missing'))
continue
version = installed[name]
if version < low: result.append((name, 'low'))
elif version >= high: result.append((name, 'high'))
return result
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve([], {}), [])
check('fixture 2', solve([('a', 1, 3, False)], {}), [('a', 'missing')])
check('fixture 3', solve([('a', 1, 3, True)], {}), [])
check('fixture 4', solve([('a', 1, 3, False)], {'a': 0}), [('a', 'low')])
check('fixture 5', solve([('a', 1, 3, False)], {'a': 1}), [])
check('fixture 6', solve([('a', 1, 3, False)], {'a': 2}), [])
check('fixture 7', solve([('a', 1, 3, False)], {'a': 3}), [('a', 'high')])
check('fixture 8', solve([('a', 1, 3, False)], {'a': 4}), [('a', 'high')])
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | [] | [] | Passed |
| fixture 2 | [['a', 'missing']] | [['a', 'missing']] | Passed |
| fixture 3 | [] | [] | Passed |
| fixture 4 | [['a', 'low']] | [['a', 'low']] | Passed |
| fixture 5 | [] | [] | Passed |
| fixture 6 | [] | [] | Passed |
| fixture 7 | [['a', 'high']] | [['a', 'high']] | Passed |
| fixture 8 | [['a', 'high']] | [['a', 'high']] | Passed |
SHA-256 / ce7871ca447a0375c01414401f4069f99495a3b156059158d057f3ca3c2d867d
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 2026-09-29T14:38:30.205852+00:00.
Case digest / 443dad90fe7e280e3e535f59459d1569d2421b9c442cb69b91d6bb8a077d67c7