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
echo "# revision 0"
echo "unchanged" > unchanged
echo "remove me" > remove
echo "copy me" > copy
echo "move me" > move
for i in 1 2 3 4 5 6 7 8 9; do
echo "merge ok $i" >> zzz1_merge_ok
done
echo "merge bad" > zzz2_merge_bad
hg ci -Am "revision 0" -d "1000000 0"
echo "# revision 1"
hg rm remove
hg mv move moved
hg cp copy copied
echo "added" > added
hg add added
echo "new first line" > zzz1_merge_ok
hg cat zzz1_merge_ok >> zzz1_merge_ok
echo "new last line" >> zzz2_merge_bad
hg ci -m "revision 1" -d "1000000 0"
echo "# local changes to revision 0"
hg co 0
echo "new last line" >> zzz1_merge_ok
echo "another last line" >> zzz2_merge_bad
hg diff --nodates | grep "^[+-][^<>]"
hg st
echo "# local merge with bad merge tool"
HGMERGE=false hg co
hg co 0
hg diff --nodates | grep "^[+-][^<>]"
hg st
echo "# local merge with conflicts"
hg co
hg co 0
hg diff --nodates | grep "^[+-][^<>]"
hg st
echo "# local merge without conflicts"
hg revert zzz2_merge_bad
hg co
hg diff --nodates | grep "^[+-][^<>]"
hg st