tests/test-addremove-similar.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)

adding empty-file
adding large-file
adding another-file
removing empty-file
removing large-file
recording removal of large-file as rename to another-file (99% similar)
% comparing two empty files caused ZeroDivisionError in the past
2 files updated, 0 files merged, 1 files removed, 0 files unresolved
adding another-empty-file
removing empty-file
adding large-file
adding tiny-file
removing large-file
adding small-file
removing tiny-file
recording removal of tiny-file as rename to small-file (82% similar)
% should all fail
abort: similarity must be a number
abort: similarity must be between 0 and 100
abort: similarity must be between 0 and 100
% issue 1527
removing d/a
adding d/b
recording removal of d/a as rename to d/b (100% similar)
r   0          0 1970-01-01 00:00:00 d/a
a   0         -1 unset               d/b
copy: d/a -> d/b
% no copies found here (since the target isn't in d
removing d/b
% copies here
adding c
recording removal of d/a as rename to c (100% similar)