FA-4631 / Iterator consumption / Open access

All short circuit consumption · case 01

The operation returns a result or retained state that violates this contract: Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Materializing input eagerly consumes values after the first false item.

VERIFIED REPAIR

Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true.

Unsuccessful approach: Inspecting only the first value misses later failures and mishandles empty input.

Case contract

Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.

Why this case matters

A controlled local-runtime regression for collection APIs, language semantics, or ownership wrappers. Fixtures include boundary and interaction cases.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import itertools as it
from collections import deque
N = 1
observations = []
def solve(x, y=None):
    g=iter(x); a=all(list(g)); return [a,list(g)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('first false stops', solve([True, False, True]), [False, [True]])
check('initial false', solve([False, True]), [False, [True]])
check('all true', solve([True, True]), [True, []])
check('empty', solve([]), [True, []])
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
first false stops	`[False, []]`	`[False, [True]]`	Failed
initial false	`[False, []]`	`[False, [True]]`	Failed
all true	`[True, []]`	`[True, []]`	Passed
empty	`[True, []]`	`[True, []]`	Passed

SHA-256 / 65492d35103ae0a0612fed9ea12e8a9c840ec70f620d8226c1ddb38883e46bd8

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import itertools as it
from collections import deque
N = 1
observations = []
def solve(x, y=None):
    g=iter(x); a=bool(next(g,False)); return [a,list(g)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('first false stops', solve([True, False, True]), [False, [True]])
check('initial false', solve([False, True]), [False, [True]])
check('all true', solve([True, True]), [True, []])
check('empty', solve([]), [True, []])
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
first false stops	`[True, [False, True]]`	`[False, [True]]`	Failed
initial false	`[False, [True]]`	`[False, [True]]`	Passed
all true	`[True, [True]]`	`[True, []]`	Failed
empty	`[False, []]`	`[True, []]`	Failed

SHA-256 / d66ce06fcf8285c698ee2ecb54ff8d7c2fcce0677f430245dfb25770feb7a738

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import itertools as it
from collections import deque
N = 1
observations = []
def solve(x, y=None):
    g=iter(x); a=all(g); return [a,list(g)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('first false stops', solve([True, False, True]), [False, [True]])
check('initial false', solve([False, True]), [False, [True]])
check('all true', solve([True, True]), [True, []])
check('empty', solve([]), [True, []])
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
first false stops	`[False, [True]]`	`[False, [True]]`	Passed
initial false	`[False, [True]]`	`[False, [True]]`	Passed
all true	`[True, []]`	`[True, []]`	Passed
empty	`[True, []]`	`[True, []]`	Passed

SHA-256 / 3800429b15e5aaf0d2af6372ce376b13edd926e41dc33d46498649bb96c9f343

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 2026-09-29T14:37:41.312686+00:00.

Case digest / f25d590a8795271231345d32b250636643f3b5451068a50e1c68a1f20dc2f52b