convert: don't drop missing or corrupt tag entries Cleaning up the tags file could be a useful feature in some cases, so maybe there should be a switch for this. However, the default hg -> hg convert tries to maintain identical hashes (thus convert.hg.saverev is off by default, but is on by default for other source types). It looks like _rewritesubstate() has a `continue` in it, and therefore a similar problem. I ran into this conversion divergence when a coworker "merged" two repositories by copy/pasting all of the files from the source repo and massaging the code, and forgetting to revert the .hg* files. That silently emptied the .hgtags file after the conversion. (This isn't the manifest node bug Yuya has been helping with- this occurred well after the bzr -> hg conversion and wasn't a merge commit, which made it extra puzzling. That bug is still an issue.)