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Differential D8094

tags: show how hg behaves if a tags cache entry is truncated
ClosedPublic

Authored by valentin.gatienbaron on Feb 7 2020, 4:35 PM.

Details

Reviewers
pulkit
Group Reviewers
hg-reviewers
Commits
rHG89d44cfcdeeb: tags: show how hg behaves if a tags cache entry is truncated
Summary

I'm seeing an error of this form in production on the order of once a
month. I'm not sure how it happens, but I suspect interrupting a pull
might result in half written cache entries.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Revision Contents
Changeset List

PathPackages
Mtests/test-tags.t (20 lines)

Diff 20055

tests/test-tags.t

$ hg blackbox -l 6 $ hg blackbox -l 6
1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags 1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags
1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing 24 bytes to cache/hgtagsfnodes1 1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing 24 bytes to cache/hgtagsfnodes1
1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> 3/4 cache hits/lookups in * seconds (glob) 1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> 3/4 cache hits/lookups in * seconds (glob)
1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing .hg/cache/tags2-visible with 1 tags 1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing .hg/cache/tags2-visible with 1 tags
1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags exited 0 after * seconds (glob) 1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> blackbox -l 6 1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> blackbox -l 6
Junk data + missing cache entries results in hg further corrupting the
cache, then failing.
$ rm -f .hg/cache/tags2-visible
$ truncate .hg/cache/hgtagsfnodes1 -s -10
$ hg debugtagscache | tail -2
4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d
5 8dbfe60eff306a54259cfe007db9e330e7ecf866 0c04f2a8af31de17fab7ffffffffffffffffffff
$ hg tags
abort: data/.hgtags.i@0c04f2a8af31: no match found!
[255]
$ hg debugtagscache | tail -2
4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d
5 8dbfe60eff306a54259cfe007db9e330e7ecf866 0c04f2a8af31de17fab7ffffffffffffffffffff
# fix up the cache
$ rm .hg/cache/hgtagsfnodes1
$ hg tags -q
tip
bar
#if unix-permissions no-root #if unix-permissions no-root
Errors writing to .hgtags fnodes cache are silently ignored Errors writing to .hgtags fnodes cache are silently ignored
$ echo dummy2 > foo $ echo dummy2 > foo
$ hg commit -m throwaway2 $ hg commit -m throwaway2
$ chmod a-w .hg/cache/hgtagsfnodes1 $ chmod a-w .hg/cache/hgtagsfnodes1
$ rm -f .hg/cache/tags2-visible $ rm -f .hg/cache/tags2-visible