comparison tests/test-fncache.t @ 25652:2882d6886919

repair: add functionality to rebuild fncache

Currently, there is no way to recover from a missing or corrupt fncache
file in place (a clone is required). For certain use cases such as
servers and with large repositories, an in-place repair may be
desirable. This patch adds functionality for in-place repair of the
fncache.

The `hg debugrebuildfncache` command is introduced. It ensures the
fncache is up to date by reconstructing the fncache from all seen files
encountered during a brute force traversal of the repository's entire
history.

The command will add missing entries and will prune excess ones.

Currently, the command no-ops unless the repository has the fncache
requirement. The command could later grow the ability to "upgrade" an
existing repository to be fncache enabled, if desired.

When testing this patch on a local clone of the Firefox repository, it
removed a bunch of entries. Investigation revealed that removed entries
belonged to empty (0 byte size) .i filelogs. The functionality for
pruning fncache of stripped revlogs was introduced in f49d60fa40a5, so
the presence of these entries likely predates this feature.

25651:125c11ec7bee

  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions
  $ cat .hg/store/fncache
  data/y.i

25652:2882d6886919

  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions
  $ cat .hg/store/fncache
  data/y.i

  $ cd ..

debugrebuildfncache does nothing unless repo has fncache requirement

  $ hg --config format.usefncache=false init nofncache
  $ cd nofncache
  $ hg debugrebuildfncache
  (not rebuilding fncache because repository does not support fncache

  $ cd ..

debugrebuildfncache works on empty repository

  $ hg init empty
  $ cd empty
  $ hg debugrebuildfncache
  fncache already up to date
  $ cd ..

debugrebuildfncache on an up to date repository no-ops

  $ hg init repo
  $ cd repo
  $ echo initial > foo
  $ echo initial > .bar
  $ hg commit -A -m initial
  adding .bar
  adding foo

  $ cat .hg/store/fncache | sort
  data/.bar.i
  data/foo.i

  $ hg debugrebuildfncache
  fncache already up to date

debugrebuildfncache restores deleted fncache file

  $ rm -f .hg/store/fncache
  $ hg debugrebuildfncache
  adding data/.bar.i
  adding data/foo.i
  2 items added, 0 removed from fncache

  $ cat .hg/store/fncache | sort
  data/.bar.i
  data/foo.i

Rebuild after rebuild should no-op

  $ hg debugrebuildfncache
  fncache already up to date

A single missing file should get restored, an extra file should be removed

  $ cat > .hg/store/fncache << EOF
  > data/foo.i
  > data/bad-entry.i
  > EOF

  $ hg debugrebuildfncache
  removing data/bad-entry.i
  adding data/.bar.i
  1 items added, 1 removed from fncache

  $ cat .hg/store/fncache | sort
  data/.bar.i
  data/foo.i

  $ cd ..

Try a simple variation without dotencode to ensure fncache is ignorant of encoding

  $ hg --config format.dotencode=false init nodotencode
  $ cd nodotencode
  $ echo initial > foo
  $ echo initial > .bar
  $ hg commit -A -m initial
  adding .bar
  adding foo

  $ cat .hg/store/fncache | sort
  data/.bar.i
  data/foo.i

  $ rm .hg/store/fncache
  $ hg debugrebuildfncache
  adding data/.bar.i
  adding data/foo.i
  2 items added, 0 removed from fncache

  $ cat .hg/store/fncache | sort
  data/.bar.i
  data/foo.i