tests/test-relink.t

rust-performance: introduce FastHashMap type alias for HashMap

Rust's default hashing is slow, because it is meant for preventing collision
attacks.
For all of the current Rust code, we don't care about those attacks, because
if an person with bad intentions has write access to your repo, you have other
issues.

I've chosen to use the TwoXHash crate because it was made by a reputable member
of the Rust community and has very good benchmarks.

For now it does not seem to improve performance by much for the current code,
but it's something else to not worry about when benchmarking code: in a
previous experiment with copytracing in Rust, it accounted for more than 10%
of the time of the entire script.

Differential Revision: https://phab.mercurial-scm.org/D7116

#require hardlink

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "relink=" >> $HGRCPATH

  $ fix_path() {
  >     tr '\\' /
  > }

  $ cat > arelinked.py <<EOF
  > from __future__ import absolute_import, print_function
  > import os
  > import sys
  > from mercurial import (
  >     pycompat,
  >     util,
  > )
  > path1, path2 = sys.argv[1:3]
  > if util.samefile(pycompat.fsencode(path1), pycompat.fsencode(path2)):
  >     print('%s == %s' % (path1, path2))
  > else:
  >     print('%s != %s' % (path1, path2))
  > EOF


create source repository

  $ hg init repo
  $ cd repo
  $ echo a > a
  $ echo b > b
  $ hg ci -Am addfile
  adding a
  adding b
  $ cat "$TESTDIR/binfile.bin" >> a
  $ cat "$TESTDIR/binfile.bin" >> b
  $ hg ci -Am changefiles

make another commit to create files larger than 1 KB to test
formatting of final byte count

  $ cat "$TESTDIR/binfile.bin" >> a
  $ cat "$TESTDIR/binfile.bin" >> b
  $ hg ci -m anotherchange

don't sit forever trying to double-lock the source repo

  $ hg relink .
  relinking $TESTTMP/repo/.hg/store to $TESTTMP/repo/.hg/store
  there is nothing to relink


Test files are read in binary mode

  $ "$PYTHON" -c "open('.hg/store/data/dummy.i', 'wb').write(b'a\r\nb\n')"
  $ cd ..


clone and pull to break links

  $ hg clone --pull -r0 repo clone
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  new changesets 008c0c271c47
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd clone
  $ hg pull -q
  $ echo b >> b
  $ hg ci -m changeb
  created new head
  $ "$PYTHON" -c "open('.hg/store/data/dummy.i', 'wb').write(b'a\nb\r\n')"


relink

#if no-reposimplestore

  $ hg relink --debug --config progress.debug=true | fix_path
  relinking $TESTTMP/repo/.hg/store to $TESTTMP/clone/.hg/store
  tip has 2 files, estimated total number of files: 3
  collecting: 00changelog.i 1/3 files (33.33%)
  collecting: 00manifest.i 2/3 files (66.67%)
  collecting: a.i 3/3 files (100.00%)
  collecting: b.i 4/3 files (133.33%)
  collecting: dummy.i 5/3 files (166.67%)
  collected 5 candidate storage files
  not linkable: 00changelog.i
  not linkable: 00manifest.i
  pruning: data/a.i 3/5 files (60.00%)
  not linkable: data/b.i
  pruning: data/dummy.i 5/5 files (100.00%)
  pruned down to 2 probably relinkable files
  relinking: data/a.i 1/2 files (50.00%)
  not linkable: data/dummy.i
  relinked 1 files (1.36 KB reclaimed)
  $ cd ..


check hardlinks

  $ "$PYTHON" arelinked.py repo/.hg/store/data/a.i clone/.hg/store/data/a.i
  repo/.hg/store/data/a.i == clone/.hg/store/data/a.i
  $ "$PYTHON" arelinked.py repo/.hg/store/data/b.i clone/.hg/store/data/b.i
  repo/.hg/store/data/b.i != clone/.hg/store/data/b.i

#endif