tests/test-rebase-cache

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

createrepo() {
    rm -rf repo
    hg init repo
    cd repo

    echo "a" > a
    hg commit -d '0 0' -A -m 'A'

    hg branch branch1
    hg commit -d '1 0' -m 'Branch1'

    echo "b" > b
    hg commit -A -d '2 0' -m 'B'

    hg up 0
    hg branch branch2
    hg commit -d '3 0' -m 'Branch2'

    echo "c" > C
    hg commit -A -d '4 0' -m 'C'

    hg up 2
    hg branch -f branch2
    echo "d" > d
    hg commit -A -d '5 0' -m 'D'

    echo "e" > e
    hg commit -A -d '6 0' -m 'E'

    hg update default

    hg branch branch3
    hg commit -d '7 0' -m 'Branch3'

    echo "f" > f
    hg commit -A -d '8 0' -m 'F'
}

echo
createrepo > /dev/null 2>&1
hg --config extensions.hgext.graphlog= glog --template '{rev}:{node|short} {desc} branch: {branches}\n'

echo
echo '% Branches'
hg branches

echo
echo '% Heads'
hg heads --template '{rev}:{node|short} {desc} branch: {branches}\n'

echo
echo '% Rebase part of branch2 (5-6) onto branch3 (8)'
hg --config extensions.hgext.rebase= rebase --detach -s 5 -d 8 2>&1 | sed 's/\(saving bundle to \).*/\1/'

echo
echo '% Branches'
hg branches

echo
echo '% Heads'
hg heads --template '{rev}:{node|short} {desc} branch: {branches}\n'

echo
hg --config extensions.hgext.graphlog= glog --template '{rev}:{node|short} {desc} branch: {branches}\n'

echo
echo '% Rebase head of branch3 (8) onto branch2 (6)'
createrepo > /dev/null 2>&1
hg --config extensions.hgext.graphlog= glog --template '{rev}:{node|short} {desc} branch: {branches}\n'

hg --config extensions.hgext.rebase= rebase --detach -s 8 -d 6 2>&1 | sed 's/\(saving bundle to \).*/\1/'

echo
echo '% Branches'
hg branches

echo
echo '% Heads'
hg heads --template '{rev}:{node|short} {desc} branch: {branches}\n'

echo
hg --config extensions.hgext.graphlog= glog --template '{rev}:{node|short} {desc} branch: {branches}\n'
hg verify -q

echo
echo '% Rebase entire branch3 (7-8) onto branch2 (6)'
createrepo > /dev/null 2>&1
hg --config extensions.hgext.graphlog= glog --template '{rev}:{node|short} {desc} branch: {branches}\n'

hg --config extensions.hgext.rebase= rebase --detach -s 7 -d 6 2>&1 | sed 's/\(saving bundle to \).*/\1/'

echo
echo '% Branches'
hg branches

echo
echo '% Heads'
hg heads --template '{rev}:{node|short} {desc} branch: {branches}\n'

echo
hg --config extensions.hgext.graphlog= glog --template '{rev}:{node|short} {desc} branch: {branches}\n'
hg verify -q