tests/test-addremove-similar

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)

#!/bin/sh

hg init rep; cd rep

touch empty-file
python -c 'for x in range(10000): print x' > large-file

hg addremove

hg commit -m A

rm large-file empty-file
python -c 'for x in range(10,10000): print x' > another-file

hg addremove -s50

hg commit -m B

echo % comparing two empty files caused ZeroDivisionError in the past
hg update -C 0
rm empty-file
touch another-empty-file
hg addremove -s50

cd ..

hg init rep2; cd rep2

python -c 'for x in range(10000): print x' > large-file
python -c 'for x in range(50): print x' > tiny-file

hg addremove

hg commit -m A

python -c 'for x in range(70): print x' > small-file
rm tiny-file
rm large-file

hg addremove -s50

hg commit -m B

echo % should all fail
hg addremove -s foo
hg addremove -s -1
hg addremove -s 1e6

cd ..

echo '% issue 1527'
hg init rep3; cd rep3
mkdir d
echo a > d/a
hg add d/a
hg commit -m 1

mv d/a d/b
hg addremove -s80
hg debugstate
mv d/b c
echo "% no copies found here (since the target isn't in d"
hg addremove -s80 d
echo "% copies here"
hg addremove -s80

true