docs(code-runtime-python): list the unknown-binding preview cap as the eleventh no-fail-before fix

The review's warning: the settlement note's Problem paragraph says ten fixes
have no fail-before test, but the unknown-binding preview cap (a transient
whole-target JSON.stringify peak, unmeasurable through the seam) is the
eleventh. The count and the item are now recorded, paired.
This commit is contained in:
Chinesezjc 2026-08-27 22:01:47 +08:00 • committed by Tianyi Cui
parent 391e29ec8a
commit 200703a20d
3 changed files with 4 additions and 4 deletions

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@ -2,5 +2,5 @@
# side as of the last confirmed-consistent state. Both languages carry equal authority;
# after editing either side, bring the other along and re-record with:
# pnpm run verify-translation-pairing --write .agents/notes/implemented/bug-fix/2026-07-31-code-runtime-python-settlement-fixes.md
2026-07-31-code-runtime-python-settlement-fixes.md: 62342c5ca6cd0d7454c122416b5176bd623c4063
2026-07-31-code-runtime-python-settlement-fixes.zh.md: d8c48459b61890d856bc960bb935788a422e7188
2026-07-31-code-runtime-python-settlement-fixes.md: a5a5190497c6852df17af59ceedfd036089719d2
2026-07-31-code-runtime-python-settlement-fixes.zh.md: 25d70c4ed419d941ab2a577a545f1030ee18004f

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@ -6,7 +6,7 @@ English | [中文](2026-07-31-code-runtime-python-settlement-fixes.zh.md)
## Problem
The CPython subprocess backend for Code Mode, built on the [fd-3 frame protocol](../architecture/2026-07-31-code-runtime-python-fd3-protocol.md), resolves every program outcome as a `CodeRunResult`, rejects `run()` only for seam misuse, and disposes to quiescence so no subprocess that stays in the child's process group outlives the fiber (a descendant that escapes the group with `setsid()` is the documented exception — see the package README's Known Limitations). A sequence of review passes surfaced defects that broke those contracts in ways unit coverage did not catch — each hid behind a `/* v8 ignore */`, a captured-callable that read as a fix but was not, a memory effect invisible through the seam, a load-time bound that double-counted, a process-group escalation that a survivor could outlast, a cross-event-loop completion that silently deadlocked, a synchronous throw outside the settlement path, or a transport boundary rendered as a log boundary. Most behavioral fixes ship with a test that fails without them; ten do not, and are called out as such — the chunked frame read (a syscall-count improvement with no cross-platform-deterministic failure), the confirmed-empty finalize (its only seam-observable effect, a frozen heartbeat, freezes the instant SIGKILL is delivered, which the pre-fix finalize-on-delivery code also produced, and the discriminating probe is the signal-0 check the Alternatives reject as cross-environment-unreliable), the shared stdout/stderr budget (its only seam-observable difference is which entry boundary a mid-stream flush lands on, and that depends on the relative arrival timing of two independent OS pipes, which `os.sched_yield` does not make deterministic; the per-pipe memory bounds it strengthens ARE covered by the single-pipe flood tests), the `flush_line` join-clear-push reorder (it lowers the settlement-flush peak from three copies to two, but the 12x load gate already covers the three-copy newline path, so every gate-admitted config stays within the address space under both orders and no seam-observable difference exists — the memory effect is inside the Python child, unmeasurable through the seam like the shared-budget case), pacing binding replies (its in-tree case only asserts the framed replies still round-trip; the peak it removes lives inside the host's fd-3 writable buffer, unseen through the seam, so the 32.0 MiB → 0.0 MiB reduction is measurable only out-of-tree), dropping a late binding resolution before snapshot (its three assertions all also hold pre-fix, because `sendReply` already dropped after-settlement values — just later than the snapshot), the done-value TOCTOU pre-encoding (a concurrent mutation racing the encode cannot be deterministically constructed through the seam — its daemon-mutation regression only asserts the result is never a `worker-exit`, which is probabilistic and non-discriminating, so under the existing no-fail-before-with-a-reason precedent it is registered as no-fail-before), the stray-UTF-8 budget-flush retention (a budget flush landing exactly on a multibyte boundary is not schedulable through the seam; it is cross-referenced as v8-ignored), and the late-rejection settled guard (a rejection arriving after the run has already settled cannot be deterministically constructed from the seam), and the log-fragment seal (a 25 M single-character drip that would OOM is not deterministically constructible in CI; the in-tree case only asserts it completes and truncates).
The CPython subprocess backend for Code Mode, built on the [fd-3 frame protocol](../architecture/2026-07-31-code-runtime-python-fd3-protocol.md), resolves every program outcome as a `CodeRunResult`, rejects `run()` only for seam misuse, and disposes to quiescence so no subprocess that stays in the child's process group outlives the fiber (a descendant that escapes the group with `setsid()` is the documented exception — see the package README's Known Limitations). A sequence of review passes surfaced defects that broke those contracts in ways unit coverage did not catch — each hid behind a `/* v8 ignore */`, a captured-callable that read as a fix but was not, a memory effect invisible through the seam, a load-time bound that double-counted, a process-group escalation that a survivor could outlast, a cross-event-loop completion that silently deadlocked, a synchronous throw outside the settlement path, or a transport boundary rendered as a log boundary. Most behavioral fixes ship with a test that fails without them; eleven do not, and are called out as such — the chunked frame read (a syscall-count improvement with no cross-platform-deterministic failure), the confirmed-empty finalize (its only seam-observable effect, a frozen heartbeat, freezes the instant SIGKILL is delivered, which the pre-fix finalize-on-delivery code also produced, and the discriminating probe is the signal-0 check the Alternatives reject as cross-environment-unreliable), the shared stdout/stderr budget (its only seam-observable difference is which entry boundary a mid-stream flush lands on, and that depends on the relative arrival timing of two independent OS pipes, which `os.sched_yield` does not make deterministic; the per-pipe memory bounds it strengthens ARE covered by the single-pipe flood tests), the `flush_line` join-clear-push reorder (it lowers the settlement-flush peak from three copies to two, but the 12x load gate already covers the three-copy newline path, so every gate-admitted config stays within the address space under both orders and no seam-observable difference exists — the memory effect is inside the Python child, unmeasurable through the seam like the shared-budget case), pacing binding replies (its in-tree case only asserts the framed replies still round-trip; the peak it removes lives inside the host's fd-3 writable buffer, unseen through the seam, so the 32.0 MiB → 0.0 MiB reduction is measurable only out-of-tree), dropping a late binding resolution before snapshot (its three assertions all also hold pre-fix, because `sendReply` already dropped after-settlement values — just later than the snapshot), the done-value TOCTOU pre-encoding (a concurrent mutation racing the encode cannot be deterministically constructed through the seam — its daemon-mutation regression only asserts the result is never a `worker-exit`, which is probabilistic and non-discriminating, so under the existing no-fail-before-with-a-reason precedent it is registered as no-fail-before), the stray-UTF-8 budget-flush retention (a budget flush landing exactly on a multibyte boundary is not schedulable through the seam; it is cross-referenced as v8-ignored), and the late-rejection settled guard (a rejection arriving after the run has already settled cannot be deterministically constructed from the seam), and the log-fragment seal (a 25 M single-character drip that would OOM is not deterministically constructible in CI; the in-tree case only asserts it completes and truncates), and the unknown-binding preview cap (the whole-target `JSON.stringify` peak is a transient allocation inside the reply path — its only seam-observable trace is peak memory under a forged near-ceiling `global`/`name`, not measurable through the seam; the in-tree case only asserts the run completes).
## Decision

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## Problem
用于 Code Mode 的 CPython 子进程后端建立在 [fd-3 帧协议](../architecture/2026-07-31-code-runtime-python-fd3-protocol.md)之上,把每个程序结果都 resolve 成一个 `CodeRunResult`,仅在 seam 被误用时才 reject `run()`,并且会 dispose 到完全停稳,从而没有任何留在子进程自己进程组内的子进程存活得比 fiber 更久(一个用 `setsid()` 逃出该进程组的后代是有文档记载的例外——见该包 README 的 Known Limitations)。一连串审查暴露出一些缺陷,它们以单元测试覆盖率无法捕获的方式破坏了这些契约:每一个都藏在一处 `/* v8 ignore */` 之后、一个读起来像修复但实际并非修复的捕获可调用对象之后、一处透过 seam 不可见的内存效应之后、一处重复计数的加载期上界之后、一处存活者能够熬过的进程组升级之后、一处静默死锁的跨事件循环完成之后、一处位于结算路径之外的同步抛出之后,或者一处被当作日志边界处理的传输边界之后。大多数行为修复都附带一个在缺少它时会失败的测试;有十处没有,并被如此标注——分块读取帧(一处系统调用次数的改进,没有可跨平台确定性断言的失败)、确认为空后的收尾(它唯一透过 seam 可观测的效应,即一个冻结的心跳,会在 SIGKILL 被投递的瞬间冻结,而修复前"投递即收尾"的代码也会产生同样的结果,用于区分的探测手段是 Alternatives 以跨环境不可靠为由否决的 signal-0 检查)、共享的 stdout/stderr 预算(它唯一透过 seam 可观测的差异,是一次流中冲刷落在哪条条目边界上,而这取决于两条相互独立的 OS 管道的相对到达时机,`os.sched_yield` 并不能使其确定;它所强化的按管道计的内存界限确实由单管道洪泛测试覆盖),`flush_line` 的 join-清空-push 重排序(它把结算期冲刷的峰值从三份副本降到两份,但 12× 加载门本就覆盖了换行路径的三副本峰值,因此每个被门放行的配置在两种顺序下都落在地址空间之内、不存在透过 seam 可观测的差异——该内存效应在 Python 子进程内部,与共享预算那处一样无法透过 seam 度量),节流 binding 回复(它的树内用例只断言分帧后的回复仍能完整往返;它所移除的峰值位于宿主 fd-3 可写缓冲内部、透过 seam 不可见,因此 32.0 MiB → 0.0 MiB 的降幅只能在树外度量),以及在快照之前丢弃迟到的 binding 解析(它的三条断言在修复前同样成立,因为 `sendReply` 本就丢弃结算之后的值——只是比快照晚),完成值的 TOCTOU 预编码(与编码竞态的并发变异无法透过 seam 确定性构造——它的 daemon 变异回归只断言结果永不为 `worker-exit`,这种断言是概率性的、不具有判别力,因此按既有的"无 fail-before 测试且有理由"先例登记为无 fail-before)、stray UTF-8 预算冲刷的扣留(正好落在多字节边界上的预算冲刷无法透过 seam 调度;它被交叉标注为 v8-ignored),以及结算后到达的迟到拒绝的 settled 先查(在运行已经结算之后才到达的拒绝无法从 seam 确定性构造),以及日志分片封存(25 M 级单字符滴灌 OOM 无法在 CI 确定性构造;树内用例只断言其完成并截断)。
用于 Code Mode 的 CPython 子进程后端建立在 [fd-3 帧协议](../architecture/2026-07-31-code-runtime-python-fd3-protocol.zh.md)之上,把每个程序结果都 resolve 成一个 `CodeRunResult`,仅在 seam 被误用时才 reject `run()`,并且会 dispose 到完全停稳,从而没有任何留在子进程自己进程组内的子进程存活得比 fiber 更久(一个用 `setsid()` 逃出该进程组的后代是有文档记载的例外——见该包 README 的 Known Limitations)。一连串审查暴露出一些缺陷,它们以单元测试覆盖率无法捕获的方式破坏了这些契约:每一个都藏在一处 `/* v8 ignore */` 之后、一个读起来像修复但实际并非修复的捕获可调用对象之后、一处透过 seam 不可见的内存效应之后、一处重复计数的加载期上界之后、一处存活者能够熬过的进程组升级之后、一处静默死锁的跨事件循环完成之后、一处位于结算路径之外的同步抛出之后,或者一处被当作日志边界处理的传输边界之后。大多数行为修复都附带一个在缺少它时会失败的测试;有十一处没有,并被如此标注——分块读取帧(一处系统调用次数的改进,没有可跨平台确定性断言的失败)、确认为空后的收尾(它唯一透过 seam 可观测的效应,即一个冻结的心跳,会在 SIGKILL 被投递的瞬间冻结,而修复前"投递即收尾"的代码也会产生同样的结果,用于区分的探测手段是 Alternatives 以跨环境不可靠为由否决的 signal-0 检查)、共享的 stdout/stderr 预算(它唯一透过 seam 可观测的差异,是一次流中冲刷落在哪条条目边界上,而这取决于两条相互独立的 OS 管道的相对到达时机,`os.sched_yield` 并不能使其确定;它所强化的按管道计的内存界限确实由单管道洪泛测试覆盖),`flush_line` 的 join-清空-push 重排序(它把结算期冲刷的峰值从三份副本降到两份,但 12× 加载门本就覆盖了换行路径的三副本峰值,因此每个被门放行的配置在两种顺序下都落在地址空间之内、不存在透过 seam 可观测的差异——该内存效应在 Python 子进程内部,与共享预算那处一样无法透过 seam 度量),节流 binding 回复(它的树内用例只断言分帧后的回复仍能完整往返;它所移除的峰值位于宿主 fd-3 可写缓冲内部、透过 seam 不可见,因此 32.0 MiB → 0.0 MiB 的降幅只能在树外度量),以及在快照之前丢弃迟到的 binding 解析(它的三条断言在修复前同样成立,因为 `sendReply` 本就丢弃结算之后的值——只是比快照晚),完成值的 TOCTOU 预编码(与编码竞态的并发变异无法透过 seam 确定性构造——它的 daemon 变异回归只断言结果永不为 `worker-exit`,这种断言是概率性的、不具有判别力,因此按既有的"无 fail-before 测试且有理由"先例登记为无 fail-before)、stray UTF-8 预算冲刷的扣留(正好落在多字节边界上的预算冲刷无法透过 seam 调度;它被交叉标注为 v8-ignored),以及结算后到达的迟到拒绝的 settled 先查(在运行已经结算之后才到达的拒绝无法从 seam 确定性构造),以及日志分片封存(25 M 级单字符滴灌 OOM 无法在 CI 确定性构造;树内用例只断言其完成并截断),以及 unknown-binding 预览上限(完整 target 的 `JSON.stringify` 峰值是回复路径内的一次瞬时分配——它唯一透过 seam 可观测的痕迹是伪造近上限 `global`/`name` 时的峰值内存,无法透过 seam 度量;树内用例只断言运行完成)。
## Decision