FA-30166 / HTTP retries / Open access

Failed response disposal and pool eligibility: New clears poison violates retry transition semantics · case 01

New clears poison violates retry transition semantics

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

New clears poison violates retry transition semantics

THE FAILURE

New clears poison violates retry transition semantics

Unsuccessful approach: The attempted repair changes the faulty site to if e[0]=='new': remaining=0; closed=True; eof=False; poison=True but still violates a regression oracle.

Case contract

headers(length) opens failed response with remaining bytes; read(count) drains bounded content. eof confirms framing only if no bytes remain, otherwise poisons connection. close marks response closed; release returns pooled only for closed, fully drained, EOF-confirmed unpoisoned response. abort permanently poisons current connection. new resets all connection state. Return drain amounts and release disposition.

Why this case matters

Offline deterministic model of HTTP request retries.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(events):
    remaining=0; closed=True; eof=False; poison=False; out=[]
    for e in events:
        if e[0]=='new': remaining=0; closed=True; eof=False; poison=poison
        elif e[0]=='headers':
            remaining=e[1]; closed=False; eof=False
        elif e[0]=='read':
            if closed: out.append('closed'); continue
            n=min(remaining,e[1]); remaining-=n; out.append(n)
        elif e[0]=='eof':
            if remaining!=0: poison=True
            else: eof=True
        elif e[0]=='close': closed=True
        elif e[0]=='abort': poison=True; closed=True
        elif e[0]=='release':
            if poison: out.append('discard')
            elif not closed: out.append('busy')
            elif remaining!=0: out.append('unread')
            elif not eof: out.append('unframed')
            else: out.append('pooled')
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('0', solve([]), [])
check('1', solve([('headers',N+3),('read',2),('read',N+9),('eof',),('release',),('close',),('release',)]), [2,N+1,'busy','pooled'])
check('2', solve([('headers',1),('close',),('read',1),('release',)]), ['closed','unread'])
check('3', solve([('headers',1),('eof',),('read',1),('close',),('release',)]), [1,'discard'])
check('4', solve([('headers',0),('close',),('release',),('eof',),('release',)]), ['unframed','pooled'])
check('5', solve([('headers',0),('eof',),('abort',),('release',),('new',),('headers',0),('eof',),('close',),('release',)]), ['discard','pooled'])
check('6', solve([('headers',0),('eof',),('close',),('headers',0),('close',),('release',)]), ['unframed'])
check('7', solve([('headers',0),('read',1)]), [0])
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
0	`[]`	`[]`	Passed
1	`[2, 2, 'busy', 'pooled']`	`[2, 2, 'busy', 'pooled']`	Passed
2	`['closed', 'unread']`	`['closed', 'unread']`	Passed
3	`[1, 'discard']`	`[1, 'discard']`	Passed
4	`['unframed', 'pooled']`	`['unframed', 'pooled']`	Passed
5	`['discard', 'discard']`	`['discard', 'pooled']`	Failed
6	`['unframed']`	`['unframed']`	Passed
7	`[0]`	`[0]`	Passed

SHA-256 / 66e2502ce0f03e0687bb96c12da7573be3cfbd6ab1dfb555dcd8a8c3e31575a9

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(events):
    remaining=0; closed=True; eof=False; poison=False; out=[]
    for e in events:
        if e[0]=='new': remaining=0; closed=True; eof=False; poison=True
        elif e[0]=='headers':
            remaining=e[1]; closed=False; eof=False
        elif e[0]=='read':
            if closed: out.append('closed'); continue
            n=min(remaining,e[1]); remaining-=n; out.append(n)
        elif e[0]=='eof':
            if remaining!=0: poison=True
            else: eof=True
        elif e[0]=='close': closed=True
        elif e[0]=='abort': poison=True; closed=True
        elif e[0]=='release':
            if poison: out.append('discard')
            elif not closed: out.append('busy')
            elif remaining!=0: out.append('unread')
            elif not eof: out.append('unframed')
            else: out.append('pooled')
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('0', solve([]), [])
check('1', solve([('headers',N+3),('read',2),('read',N+9),('eof',),('release',),('close',),('release',)]), [2,N+1,'busy','pooled'])
check('2', solve([('headers',1),('close',),('read',1),('release',)]), ['closed','unread'])
check('3', solve([('headers',1),('eof',),('read',1),('close',),('release',)]), [1,'discard'])
check('4', solve([('headers',0),('close',),('release',),('eof',),('release',)]), ['unframed','pooled'])
check('5', solve([('headers',0),('eof',),('abort',),('release',),('new',),('headers',0),('eof',),('close',),('release',)]), ['discard','pooled'])
check('6', solve([('headers',0),('eof',),('close',),('headers',0),('close',),('release',)]), ['unframed'])
check('7', solve([('headers',0),('read',1)]), [0])
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
0	`[]`	`[]`	Passed
1	`[2, 2, 'busy', 'pooled']`	`[2, 2, 'busy', 'pooled']`	Passed
2	`['closed', 'unread']`	`['closed', 'unread']`	Passed
3	`[1, 'discard']`	`[1, 'discard']`	Passed
4	`['unframed', 'pooled']`	`['unframed', 'pooled']`	Passed
5	`['discard', 'discard']`	`['discard', 'pooled']`	Failed
6	`['unframed']`	`['unframed']`	Passed
7	`[0]`	`[0]`	Passed

SHA-256 / d4cd0237d95fc9487aa21c8d981103ca185953b648bf84c6a7d01905c7250db7

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 8 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

Stipulated bounded simulator, not a complete HTTP implementation or a standards conformance claim. 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 2026-09-29T14:41:50.292388+00:00.

Case digest / 5f1029ce727cc0b884cab57b18202b1424223b008eba08ca5de8e4e836112005