FA-1256 / Workflow orchestration / Open access

Continue a workflow as a new run: Continuation discards accepted but unconsumed signals · case 01

The workflow continue operation is admitted even though continuation discards accepted but unconsumed signals.

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

ROOT CAUSE

The admission path omits the signal drain invariant while validating the other operation preconditions.

VERIFIED REPAIR

Require len(r['signal_drain']) == 0 together with every other stated precondition before accepting the operation.

Unsuccessful approach: Adding the signal drain check repairs the reported defect, but replacing the adjacent state serializable check loses that independent invariant.

Case contract

Return a Boolean admission decision for continue a workflow as a new run. The record r must satisfy all of: r['pending_activities'] == 0; len(r['signal_drain']) == 0; r['state_serializable'] in ['json','bytes']; r['new_run_unique'][0] != r['new_run_unique'][1]; r['predecessor_closed'] == 'continued'. 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 (r['pending_activities'] == 0) and (r['state_serializable'] in ['json','bytes']) and (r['new_run_unique'][0] != r['new_run_unique'][1]) and (r['predecessor_closed'] == 'continued')
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
r = {'pending_activities': 0, 'signal_drain': [], 'state_serializable': 'json', 'new_run_unique': ['r2', 'r1'], 'predecessor_closed': 'continued'}
check('valid operation', solve(r), True)
check('Continuation loses unresolved activity results', solve(dict(r, **{'pending_activities': 1})), False)
check('Continuation discards accepted but unconsumed signals', solve(dict(r, **{'signal_drain': ['approve']})), False)
check('Continuation stores a runtime handle instead of durable state', solve(dict(r, **{'state_serializable': 'socket'})), False)
check('Continuation reuses the predecessor run identifier', solve(dict(r, **{'new_run_unique': ['r1', 'r1']})), False)
check('Both predecessor and successor remain runnable', solve(dict(r, **{'predecessor_closed': 'running'})), False)
check('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)
check('repeat validation is pure', solve(r), True)
invalid = {'pending_activities': 1, 'signal_drain': ['approve'], 'state_serializable': 'socket', 'new_run_unique': ['r1', 'r1'], 'predecessor_closed': 'running'}
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
Continuation loses unresolved activity results	`False`	`False`	Passed
Continuation discards accepted but unconsumed signals	`True`	`False`	Failed
Continuation stores a runtime handle instead of durable state	`False`	`False`	Passed
Continuation reuses the predecessor run identifier	`False`	`False`	Passed
Both predecessor and successor remain runnable	`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 / 492c35dab9429af984bd0a72693821b1d8764c665d2b038965659e57ab7c17f6

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(r):
    return (r['pending_activities'] == 0) and (len(r['signal_drain']) == 0) and (r['new_run_unique'][0] != r['new_run_unique'][1]) and (r['predecessor_closed'] == 'continued')
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
r = {'pending_activities': 0, 'signal_drain': [], 'state_serializable': 'json', 'new_run_unique': ['r2', 'r1'], 'predecessor_closed': 'continued'}
check('valid operation', solve(r), True)
check('Continuation loses unresolved activity results', solve(dict(r, **{'pending_activities': 1})), False)
check('Continuation discards accepted but unconsumed signals', solve(dict(r, **{'signal_drain': ['approve']})), False)
check('Continuation stores a runtime handle instead of durable state', solve(dict(r, **{'state_serializable': 'socket'})), False)
check('Continuation reuses the predecessor run identifier', solve(dict(r, **{'new_run_unique': ['r1', 'r1']})), False)
check('Both predecessor and successor remain runnable', solve(dict(r, **{'predecessor_closed': 'running'})), False)
check('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)
check('repeat validation is pure', solve(r), True)
invalid = {'pending_activities': 1, 'signal_drain': ['approve'], 'state_serializable': 'socket', 'new_run_unique': ['r1', 'r1'], 'predecessor_closed': 'running'}
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
Continuation loses unresolved activity results	`False`	`False`	Passed
Continuation discards accepted but unconsumed signals	`False`	`False`	Passed
Continuation stores a runtime handle instead of durable state	`True`	`False`	Failed
Continuation reuses the predecessor run identifier	`False`	`False`	Passed
Both predecessor and successor remain runnable	`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 / 6b95291a06fccae16d99601befc6a3540cb5f004e13874fa02bb2b07591eacbb

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(r):
    return (r['pending_activities'] == 0) and (len(r['signal_drain']) == 0) and (r['state_serializable'] in ['json','bytes']) and (r['new_run_unique'][0] != r['new_run_unique'][1]) and (r['predecessor_closed'] == 'continued')
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
r = {'pending_activities': 0, 'signal_drain': [], 'state_serializable': 'json', 'new_run_unique': ['r2', 'r1'], 'predecessor_closed': 'continued'}
check('valid operation', solve(r), True)
check('Continuation loses unresolved activity results', solve(dict(r, **{'pending_activities': 1})), False)
check('Continuation discards accepted but unconsumed signals', solve(dict(r, **{'signal_drain': ['approve']})), False)
check('Continuation stores a runtime handle instead of durable state', solve(dict(r, **{'state_serializable': 'socket'})), False)
check('Continuation reuses the predecessor run identifier', solve(dict(r, **{'new_run_unique': ['r1', 'r1']})), False)
check('Both predecessor and successor remain runnable', solve(dict(r, **{'predecessor_closed': 'running'})), False)
check('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)
check('repeat validation is pure', solve(r), True)
invalid = {'pending_activities': 1, 'signal_drain': ['approve'], 'state_serializable': 'socket', 'new_run_unique': ['r1', 'r1'], 'predecessor_closed': 'running'}
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
Continuation loses unresolved activity results	`False`	`False`	Passed
Continuation discards accepted but unconsumed signals	`False`	`False`	Passed
Continuation stores a runtime handle instead of durable state	`False`	`False`	Passed
Continuation reuses the predecessor run identifier	`False`	`False`	Passed
Both predecessor and successor remain runnable	`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 / a3a10e6d9993e260ae8c14cf204626271aa53d1ee3ee976a6e9927230b9d4efe

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 2026-09-29T14:37:00.157826+00:00.

Case digest / 71a284d217362d693e2d8a34c15278374335059f73795f6a643aeb8004bf083e