Debians commandline package manager https://git.kalnischkies.de/apt/atom?h=main 2024-11-22T12:40:10Z 2024-11-22T12:40:10Z David Kalnischkies david@kalnischkies.de 2022-05-09T09:42:48Z urn:sha1:7adf8c1fa8d519b8b57292763eb7703e7d3cc580 Ideally copy and file mirrors would support by-hash as well, but its harder to setup and maintain especially if you want to cache an online mirror who has by-hash enabled. We can avoid unneeded roundtrips (in the best case) and entire cache misses (in the usual worst case) by "just" telling methods that the URI we passed it has the requested file perhaps also in other paths. This is done in pseudo-relative paths as we would otherwise need to teach redirection code to rewrite those URIs as well. A method like http can easily ignore this value and await explicit instructions to look at that file, but inspecting the path in local sources via file or copy is (comparatively) free, so we just do it immediately. If that ends up being the wrong version of the file as by-hash would have protected us from we are in this feature branch now falling back to other mirrors which are like the ones online and in support of by-hash. 2024-11-22T12:40:10Z David Kalnischkies david@kalnischkies.de 2022-04-29T14:58:23Z urn:sha1:15124923b4cdb19af6bf642f396dab7c3e6bd074 Perhaps a common error in the past nowadays thanks to by-hash we rarely get mismatches due to our calling behaviour and more because the mirror is genuinely bad especially if this mirror didn't work with by-hash. Using our "normal" error handling allows falling back to other mirrors which hopefully do support by-hash and/or are not broken on a filesystem level making us more resistent to the occasional bad apple in a wild mirror forest. 2024-11-22T12:21:24Z David Kalnischkies david@kalnischkies.de 2022-04-23T22:24:40Z urn:sha1:370e024224b8116840173201d51c0c2a170e0e93 If we do not have the requested file we haven't calculated the hashes for it either and it is likely that the alternative file will be used, so to save the main thread from being busy with calculating hashes we do the calculation here in the method. 2024-11-22T12:21:24Z David Kalnischkies david@kalnischkies.de 2022-04-23T22:03:38Z urn:sha1:496c8b4191790231258e644ac8cd4096d54f445f The main thread calculates the hash sums if the method hasn't to be able to verify the files, but while a failure is detected and reported, the error messages did not include the hash sums which looks at least puzzling. So to have a complete error message we ensure that the hashes we calculated are appended to the message from the method so that it looks for the higher level code as if the method had calculated the hashes. 2024-11-22T12:21:24Z David Kalnischkies david@kalnischkies.de 2022-04-23T20:46:33Z urn:sha1:39304fb440f62b3a9f4dd85871b7049fb5b8eb8f If a file:/ mirror does not contain the requested compressed file, but the uncompressed variant of that file the method will sent us a fitting Done message with data only about the Alt-Filename, but the central hash verification code in the acquire system does not expect that looking for the non-existent compressed file to compare its hashes with the expected result – which fails (if we are verifying at least). That file:/ as well as the item code deals with this suggests that this feature was broken by 448c38bdcd72b52f11ec5f326f822cf57653f81c, but I couldn't (easily) compile that to verify, so this is only a guess. Supporting this allows using index files from /var/lib/apt/lists – which are likely uncompressed or can at least made so easily – to construct a file:/ mirror.