largefiles: don't let update leave wrong largefiles in wd if fetch fails Situations where a largefile for some reason wasn't available sometimes caused wrong largefile content and state. It has mostly been seen when interrupting download of largefiles ... and when introducing programming errors. Instead we now make sure to delete the old and wrong largefile. A missing file is a well-known error condition and much more reasonable way to handle the situation.

largefiles: missing largefiles should not be committed as removed Largefiles can easily become missing - for example if it simply isn't available or the download fail. It might even be convenient to be able to work that way in some cases. But commiting missing largefiles as if they had been 'hg remove'd is plain wrong.

largefiles: don't assume that .hg/largefiles/ still exists It might not have been created and it might have been removed.

largefiles: getstandinmatcher should not depend on existence of directories Looking for a (potentially empty) directory was not reliable - both because it is a reasonable assumption that empty directories can be removed and because it wasn't created in all cases ... such as when pulling to an existing repository.

tests: don't rely on broken behaviour in test-largefiles-cache.t The test relied on the bug that 'pull largefiles from branchheads' didn't pull any largefiles from tip revision when it seemed like no largefiles had been checked out before.

largefiles: fix download of largefiles from an empty list of changesets The empty list was interpreted as all revisions - just like None is. The empty list is now handled explicitly.

largefiles: fix off-by-one error on pull --all-largefiles Test output is changed in a case where one revision was pulled, but because of the off-by-one error it thought that 0 revisions were pulled ... and because of another bug it thus (tried to) fetch largefiles for all revisions. After this change it no longer reports failure when it failed while trying to fetch largefiles it shouldn't fetch. Largefiles that it shouldn't fetch but managed to fetch anyway will now correctly be missing later on. This change thus resolves some of unexplained test output introduced in 1e4eb1faba6e.