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A storage middleware is transparent: it has an opinion about a couple of methods and everything else has to reach the storage underneath. The three in storage::middleware override pread/pwrite/remove/ensure_len/take/remove_dir/init and stop there, so on_piece_completed - the one method with a default that a storage is likely to implement - never got past the middleware. Its default does nothing, which is exactly the wrong thing to do on a storage's behalf. It is the callback a storage uses to make a piece durable or visible once it is written and hash-checked: write it under a temporary name and move it into place, flush it, promote it out of a staging area. Wrap such a storage in TimingStorage to find out why it is slow, or in the write-through cache, and the call goes to the middleware's default instead - so nothing is ever promoted, and the storage quietly stops working in the one configuration you added the middleware to debug. Forward it in all three, and check every wrapper around a storage against a probe that records the completions it was told about, so one that doesn't forward is caught. Box<U> already forwards it and now says so in a test: what a torrent holds is a Box<dyn TorrentStorage>, so a method it drops is one no storage ever gets asked. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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A storage middleware is transparent: it has an opinion about a couple of methods and everything else has to reach the storage underneath. The three in storage::middleware override pread/pwrite/remove/ensure_len/take/remove_dir/init and stop there, so on_piece_completed - the one method with a default that a storage is likely to implement - never got past the middleware.
Its default does nothing, which is exactly the wrong thing to do on a storage's behalf. It is the callback a storage uses to make a piece durable or visible once it is written and hash-checked: write it under a temporary name and move it into place, flush it, promote it out of a staging area. Wrap such a storage in TimingStorage to find out why it is slow, or in the write-through cache, and the call goes to the middleware's default instead - so nothing is ever promoted, and the storage quietly stops working in the one configuration you added the middleware to debug.
Forward it in all three, and check every wrapper around a storage against a probe that records the completions it was told about, so one that doesn't forward is caught. Box already forwards it and now says so in a test: what a torrent holds is a Box, so a method it drops is one no storage ever gets asked.
Yet another PR created by my Claude Fable, but it looks correct.