tests/test-rollback.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)

checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
changeset:   0:0acdaf898367
tag:         tip
user:        test
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     test

rolling back to revision 0 (undo commit)
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
0 files, 0 changesets, 0 total revisions
A a
% Test issue 902
marked working directory as branch test
rolling back to revision 0 (undo commit)
default
% Test issue 1635 (commit message saved)
.hg/last-message.txt:
test2
% Test rollback of hg before issue 902 was fixed
marked working directory as branch test
rolling back to revision 0 (undo commit)
Named branch could not be reset, current branch still is: test
test
% rollback by pretxncommit saves commit message (issue 1635)
transaction abort!
rollback completed
abort: pretxncommit hook exited ...
.hg/last-message.txt:
precious commit message
% same thing, but run $EDITOR
transaction abort!
rollback completed
note: commit message saved in .hg/last-message.txt
abort: pretxncommit hook exited ...
.hg/last-message.txt:
another precious commit message