tests/test-mq-safety.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)

% try to commit on top of a patch
abort: cannot commit over an applied mq patch
% qpop/qrefresh on the wrong revision
abort: popping would remove a revision not managed by this patch queue
using patch queue:
abort: popping would remove a revision not managed by this patch queue
abort: working directory revision is not qtip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
% qpop
abort: popping would remove a revision not managed by this patch queue
% qrefresh
abort: cannot refresh a revision with children
% tip:
3 append quux
% qpush warning branchheads
popping qp
patch queue now empty
adding a
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
marked working directory as branch b
adding c
created new head
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
changeset:   2:65309210bf4e
branch:      b
tag:         tip
parent:      1:707adb4c8ae1
parent:      0:cb9a9f314b8b
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     merge

changeset:   1:707adb4c8ae1
branch:      b
parent:      -1:000000000000
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     c

changeset:   0:cb9a9f314b8b
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     a

applying qp
now at: qp