view tests/test-convert-identity.t @ 51550:463e63aa547c

stream-clone: disable gc for `_entries_walk` duration

The number of small container created turn Python in a gc-frenzy that seriously
impact performance.

This significantly boost performance. The following number comes from a large
private repository using perf::stream-locked-section:

base-line:   35.04 seconds
prev-change: 24.51 seconds (-30%)
this-change: 20.88 seconds (-40% from baseline; -15% from previous changes)

Testing that convert.hg.preserve-hash=true can be used to make hg
convert from hg repo to hg repo preserve hashes, even if the
computation of the files list in commits change slightly between hg
versions.

  $ cat <<'EOF' >> "$HGRCPATH"
  > [extensions]
  > convert =
  > EOF
  $ cat <<'EOF' > changefileslist.py
  > from mercurial import (changelog, extensions, metadata)
  > def wrap(orig, clog, manifest, files, *args, **kwargs):
  >   files = metadata.ChangingFiles(touched=[b"a"])
  >   return orig(clog, manifest, files, *args, **kwargs)
  > def extsetup(ui):
  >   extensions.wrapfunction(changelog.changelog, 'add', wrap)
  > EOF

  $ hg init repo
  $ cd repo
  $ echo a > a; hg commit -qAm a
  $ echo b > a; hg commit -qAm b
  $ hg up -qr 0; echo c > c; hg commit -qAm c
  $ hg merge -qr 1
  $ hg commit -m_ --config extensions.x=../changefileslist.py
  $ hg log -r . -T '{node|short} {files|json}\n'
  c085bbe93d59 ["a"]

Now that we have a commit with a files list that's not what the
current hg version would create, check that convert either fixes it or
keeps it depending on config:

  $ hg convert -q . ../convert
  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
  b7c4d4bbacd3 []
  $ rm -rf ../convert

  $ hg convert -q . ../convert --config convert.hg.preserve-hash=true
  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
  c085bbe93d59 ["a"]
  $ rm -rf ../convert