"""用「三臂证明 + 回归检查」验收一个补丁。
受 Trail of Bits patching-bugs / regression-hunt 插件启发：
三臂证明：原代码上复现检查应失败 → 打补丁后应通过 → 撤回补丁后应再次失败
回归检查：原来通过的既有行为，打补丁后仍应通过
样例：parse_amount() 解析金额字符串，原版不支持千位分隔符（bug 报告：'1,234.50' 报错）。
两个候选补丁都能修好 bug，但其中一个顺手破坏了负数解析。
只用 Python 标准库，所有代码都在本文件中。
"""
from __future__ import annotations
import sys
ORIGINAL = '''
def parse_amount(s):
return float(s.strip())
'''
# 候选补丁 A：用正则校验格式，修好了千位分隔符，但正则漏掉了负号
PATCH_A = '''
import re
_PAT = re.compile(r"^\\d{1,3}(,\\d{3})*(\\.\\d+)?$|^\\d+(\\.\\d+)?$")
def parse_amount(s):
s = s.strip()
if not _PAT.match(s):
raise ValueError("bad amount: " + s)
return float(s.replace(",", ""))
'''
# 候选补丁 B：同样校验格式，保留可选负号
PATCH_B = '''
import re
_PAT = re.compile(r"^-?(\\d{1,3}(,\\d{3})*|\\d+)(\\.\\d+)?$")
def parse_amount(s):
s = s.strip()
if not _PAT.match(s):
raise ValueError("bad amount: " + s)
return float(s.replace(",", ""))
'''
# bug 报告对应的复现检查
BUG_CHECK = ("1,234.50", 1234.5)
# 既有的、原本就支持的行为（相当于已有的测试集）
EXISTING = [
("12.5", 12.5),
(" 7 ", 7.0),
("-3", -3.0),
("0.25", 0.25),
("1000", 1000.0),
]
def load(src: str):
ns: dict = {}
exec(src, ns) # noqa: S102 —— 只执行本文件内的固定代码
return ns["parse_amount"]
def passes(fn, case) -> bool:
inp, want = case
try:
return abs(fn(inp) - want) < 1e-9
except Exception: # noqa: BLE001
return False
def three_arm(patch: str) -> tuple[bool, list[str]]:
arms = [
("原代码", ORIGINAL, False),
("打补丁", patch, True),
("撤回补丁", ORIGINAL, False),
]
log, ok = [], True
for name, src, want in arms:
got = passes(load(src), BUG_CHECK)
good = got == want
ok &= good
log.append(f"{name}: 复现检查{'通过' if got else '失败'}（期望{'通过' if want else '失败'}）{'✓' if good else '✗'}")
return ok, log
def regressions(patch: str) -> list[str]:
before, after = load(ORIGINAL), load(patch)
return [inp for inp, want in EXISTING if passes(before, (inp, want)) and not passes(after, (inp, want))]
def main() -> int:
results = {}
for name, patch in (("补丁 A", PATCH_A), ("补丁 B", PATCH_B)):
ok, log = three_arm(patch)
regs = regressions(patch)
results[name] = (ok, regs)
print(f"== {name} ==")
for line in log:
print(" " + line)
print(f" 三臂证明：{'成立' if ok else '不成立'}")
print(f" 回归：{len(regs)} 个" + (f"，原本支持、现在失败的输入：{regs!r}" if regs else ""))
verdict = "可接受" if ok and not regs else "拒绝"
print(f" 结论：{verdict}\n")
a_ok, a_regs = results["补丁 A"]
b_ok, b_regs = results["补丁 B"]
checks = [
("两个补丁都通过三臂证明", a_ok and b_ok),
("补丁 A 被回归检查拦下（负数解析被破坏）", a_regs == ["-3"]),
("补丁 B 没有回归", b_regs == []),
]
for desc, good in checks:
print(f"[{'PASS' if good else 'FAIL'}] {desc}")
all_ok = all(g for _, g in checks)
print("\nRESULT:", "只看 bug 是否修好会接受补丁 A；加上回归检查后只接受补丁 B" if all_ok else "检查未全部通过")
return 0 if all_ok else 1
if __name__ == "__main__":
sys.exit(main())