tests/test-mq-caches.out

findrenames: Optimise "addremove -s100" by matching files by their SHA1 hashes.

We speed up 'findrenames' for the usecase when a user specifies they
want a similarity of 100% by matching files by their exact SHA1 hash
value. This reduces the number of comparisons required to find exact
matches from O(n^2) to O(n).

While it would be nice if we could just use mercurial's pre-calculated
SHA1 hash for existing files, this hash includes the file's ancestor
information making it unsuitable for our purposes. Instead, we calculate
the hash of old content from scratch.

The following benchmarks were taken on the current head of crew:

addremove 100% similarity:
  rm -rf *; hg up -C; mv tests tests.new
  hg --time addremove -s100 --dry-run

  before:  real 176.350 secs (user 128.890+0.000 sys 47.430+0.000)
  after:   real   2.130 secs (user   1.890+0.000 sys  0.240+0.000)

addremove 75% similarity:
  rm -rf *; hg up -C; mv tests tests.new; \
      for i in tests.new/*; do echo x >> $i; done
  hg --time addremove -s75  --dry-run

  before: real 264.560 secs (user 215.130+0.000 sys 49.410+0.000)
  after:  real 218.710 secs (user 172.790+0.000 sys 45.870+0.000)

# mq patch on an empty repo
tip: 0
No branch cache
tip: 0
No branch cache

# some regular revisions
popping p1
patch queue now empty
tip: 1
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo

# add some mq patches
applying p1
now at: p1
tip: 2
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
tip: 3
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
branch foo: 3
branch bar: 2

# removing the cache
tip: 3
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
branch foo: 3
branch bar: 2

# importing rev 1 (the cache now ends in one of the patches)
tip: 3
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
branch foo: 3
branch bar: 2
qbase: 1

# detect an invalid cache
popping p2
popping p1
popping p0
patch queue now empty
applying p0
applying p1
applying p2
now at: p2
tip: 3
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff 0
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo