PropagateDownload: Skip identical files more #6168
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ckamm
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ogoffart
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Nov 16, 2017
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The problem is that the checksum might not be sufficiently good.
Before, we were considering that the fact that the size and mtime was the same was a sufficiently good indication that the file was similar.
But now, if the mtime is also different, this is too much to just rely on the checksum.
src/libsync/propagatedownload.cpp
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| // compare the remote checksum to the local one. | ||
| // Maybe it's not a real conflict and no download is necessary! | ||
| if (_item->_instruction == CSYNC_INSTRUCTION_CONFLICT | ||
| && _item->_size == _item->_previousSize | ||
| && _item->_modtime == _item->_previousModtime |
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I'd change that to
_item->_modtime == _item->_previousModtime || isChecksumSufficientlyGood
|
Use case to check the mtime here, is that if somebody deletes the database and do a sync again, not everything should be conflictsn even if there is no hashes or that the hashes are week. |
Previously we required matching mtimes but that's actually unnecessary when the question is about whether to skip the download. We will still update the file's metadata. Also, adjust behavior when the checksum is weak (Adler32): in these cases we still depend on equal mtimes.
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This was referenced May 9, 2023
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Previously we required matching mtimes but that's actually
unnecessary when the question is about whether to skip the
download. We will still update the downloaded file's metadata.
See #6153