FA-1321 / Workflow orchestration / Open access

Release a workflow dependency join: A cancelled required branch is silently omitted · case 01

The workflow join operation is admitted even though a cancelled required branch is silently omitted.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The admission path omits the cancelled branch invariant while validating the other operation preconditions.

VERIFIED REPAIR

Require not any(r['cancelled_branch']) together with every other stated precondition before accepting the operation.

Unsuccessful approach: Adding the cancelled branch check repairs the reported defect, but replacing the adjacent all required check loses that independent invariant.

Case contract

Return a Boolean admission decision for release a workflow dependency join. The record r must satisfy all of: set(r['all_required'][0]) <= set(r['all_required'][1]); all(x == 'success' for x in r['success_policy']); all(x == r['branch_generation'][0] for x in r['branch_generation'][1]); r['release_once'] is False; not any(r['cancelled_branch']). Extra tracing fields are ignored; validation does not mutate the record.

Why this case matters

A deterministic local contract for workflow orchestration. Each negative fixture violates exactly one invariant. No transport timing, persistence, cryptographic verification, or full protocol implementation is claimed.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(r):
    return (set(r['all_required'][0]) <= set(r['all_required'][1])) and (all(x == 'success' for x in r['success_policy'])) and (all(x == r['branch_generation'][0] for x in r['branch_generation'][1])) and (r['release_once'] is False)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
r = {'all_required': [['a', 'b'], ['a', 'b']], 'success_policy': ['success', 'success'], 'branch_generation': [3, [3, 3]], 'release_once': False, 'cancelled_branch': [False, False]}
check('valid operation', solve(r), True)
check('A join proceeds before every required predecessor completes', solve(dict(r, **{'all_required': [['a', 'b'], ['a']]})), False)
check('A success-only join treats failed predecessors as successful', solve(dict(r, **{'success_policy': ['success', 'failed']})), False)
check('A completion from a previous loop iteration satisfies the join', solve(dict(r, **{'branch_generation': [3, [2, 3]]})), False)
check('Duplicate predecessor events release the join twice', solve(dict(r, **{'release_once': True})), False)
check('A cancelled required branch is silently omitted', solve(dict(r, **{'cancelled_branch': [False, True]})), False)
check('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)
check('repeat validation is pure', solve(r), True)
invalid = {'all_required': [['a', 'b'], ['a']], 'success_policy': ['success', 'failed'], 'branch_generation': [3, [2, 3]], 'release_once': True, 'cancelled_branch': [False, True]}
keys = list(invalid)
pair = {keys[N % len(keys)]: invalid[keys[N % len(keys)]], keys[(N+1) % len(keys)]: invalid[keys[(N+1) % len(keys)]]}
check('two independent violations in variant', solve(dict(r, **pair)), False)
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
valid operation	`True`	`True`	Passed
A join proceeds before every required predecessor completes	`False`	`False`	Passed
A success-only join treats failed predecessors as successful	`False`	`False`	Passed
A completion from a previous loop iteration satisfies the join	`False`	`False`	Passed
Duplicate predecessor events release the join twice	`False`	`False`	Passed
A cancelled required branch is silently omitted	`True`	`False`	Failed
unrelated tracing metadata	`True`	`True`	Passed
repeat validation is pure	`True`	`True`	Passed
two independent violations in variant	`False`	`False`	Passed

SHA-256 / 1e83c106a6ea97150a7a40ef56337a68080802ed7989f8cdedc736ebfb5fb976

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(r):
    return (all(x == 'success' for x in r['success_policy'])) and (all(x == r['branch_generation'][0] for x in r['branch_generation'][1])) and (r['release_once'] is False) and (not any(r['cancelled_branch']))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
r = {'all_required': [['a', 'b'], ['a', 'b']], 'success_policy': ['success', 'success'], 'branch_generation': [3, [3, 3]], 'release_once': False, 'cancelled_branch': [False, False]}
check('valid operation', solve(r), True)
check('A join proceeds before every required predecessor completes', solve(dict(r, **{'all_required': [['a', 'b'], ['a']]})), False)
check('A success-only join treats failed predecessors as successful', solve(dict(r, **{'success_policy': ['success', 'failed']})), False)
check('A completion from a previous loop iteration satisfies the join', solve(dict(r, **{'branch_generation': [3, [2, 3]]})), False)
check('Duplicate predecessor events release the join twice', solve(dict(r, **{'release_once': True})), False)
check('A cancelled required branch is silently omitted', solve(dict(r, **{'cancelled_branch': [False, True]})), False)
check('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)
check('repeat validation is pure', solve(r), True)
invalid = {'all_required': [['a', 'b'], ['a']], 'success_policy': ['success', 'failed'], 'branch_generation': [3, [2, 3]], 'release_once': True, 'cancelled_branch': [False, True]}
keys = list(invalid)
pair = {keys[N % len(keys)]: invalid[keys[N % len(keys)]], keys[(N+1) % len(keys)]: invalid[keys[(N+1) % len(keys)]]}
check('two independent violations in variant', solve(dict(r, **pair)), False)
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
valid operation	`True`	`True`	Passed
A join proceeds before every required predecessor completes	`True`	`False`	Failed
A success-only join treats failed predecessors as successful	`False`	`False`	Passed
A completion from a previous loop iteration satisfies the join	`False`	`False`	Passed
Duplicate predecessor events release the join twice	`False`	`False`	Passed
A cancelled required branch is silently omitted	`False`	`False`	Passed
unrelated tracing metadata	`True`	`True`	Passed
repeat validation is pure	`True`	`True`	Passed
two independent violations in variant	`False`	`False`	Passed

SHA-256 / ab838913ff681701c1288c57d1ede3abd2d07fdd8c5ef42258b093313a9dfdd9

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(r):
    return (set(r['all_required'][0]) <= set(r['all_required'][1])) and (all(x == 'success' for x in r['success_policy'])) and (all(x == r['branch_generation'][0] for x in r['branch_generation'][1])) and (r['release_once'] is False) and (not any(r['cancelled_branch']))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
r = {'all_required': [['a', 'b'], ['a', 'b']], 'success_policy': ['success', 'success'], 'branch_generation': [3, [3, 3]], 'release_once': False, 'cancelled_branch': [False, False]}
check('valid operation', solve(r), True)
check('A join proceeds before every required predecessor completes', solve(dict(r, **{'all_required': [['a', 'b'], ['a']]})), False)
check('A success-only join treats failed predecessors as successful', solve(dict(r, **{'success_policy': ['success', 'failed']})), False)
check('A completion from a previous loop iteration satisfies the join', solve(dict(r, **{'branch_generation': [3, [2, 3]]})), False)
check('Duplicate predecessor events release the join twice', solve(dict(r, **{'release_once': True})), False)
check('A cancelled required branch is silently omitted', solve(dict(r, **{'cancelled_branch': [False, True]})), False)
check('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)
check('repeat validation is pure', solve(r), True)
invalid = {'all_required': [['a', 'b'], ['a']], 'success_policy': ['success', 'failed'], 'branch_generation': [3, [2, 3]], 'release_once': True, 'cancelled_branch': [False, True]}
keys = list(invalid)
pair = {keys[N % len(keys)]: invalid[keys[N % len(keys)]], keys[(N+1) % len(keys)]: invalid[keys[(N+1) % len(keys)]]}
check('two independent violations in variant', solve(dict(r, **pair)), False)
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
valid operation	`True`	`True`	Passed
A join proceeds before every required predecessor completes	`False`	`False`	Passed
A success-only join treats failed predecessors as successful	`False`	`False`	Passed
A completion from a previous loop iteration satisfies the join	`False`	`False`	Passed
Duplicate predecessor events release the join twice	`False`	`False`	Passed
A cancelled required branch is silently omitted	`False`	`False`	Passed
unrelated tracing metadata	`True`	`True`	Passed
repeat validation is pure	`True`	`True`	Passed
two independent violations in variant	`False`	`False`	Passed

SHA-256 / 6668b62a3353434e7dc560f349296dbc5221eaabe9e1fa91d6fd09b5166472cb

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 2026-09-29T14:37:00.957343+00:00.

Case digest / 94226f2e07653621ac2a9d676f4aa0b9dd4228a3bc854dcb5c647bedfb98451c