tests/test-remotefilelog-partial-shallow.t

revlog: add a C implementation of `headrevsdiff`

Python implementation of `headrevsdiff` can be very slow in the worst
case compared with the `heads` computation it replaces, since the
latter is done in C.

Even the average case of this Python implementation is still
noticeable in the profiles.

This patch makes the computation much much faster by doing it in C.

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > foo
  $ echo y > bar
  $ hg commit -qAm one

  $ cd ..

# partial shallow clone

  $ hg clone --shallow ssh://user@dummy/master shallow --noupdate --config remotefilelog.includepattern=foo
  streaming all changes
  4 files to transfer, 336 bytes of data (no-zstd !)
  transferred 336 bytes in * seconds (* */sec) (glob) (no-zstd !)
  4 files to transfer, 338 bytes of data (zstd no-rust !)
  transferred 338 bytes in * seconds (* */sec) (glob) (zstd no-rust !)
  6 files to transfer, 464 bytes of data (zstd rust !)
  transferred 464 bytes in * seconds (*/sec) (glob) (zstd rust !)
  searching for changes
  no changes found
  $ cat >> shallow/.hg/hgrc <<EOF
  > [remotefilelog]
  > cachepath=$PWD/hgcache
  > debug=True
  > includepattern=foo
  > reponame = master
  > [extensions]
  > remotefilelog=
  > EOF
  $ ls shallow/.hg/store/data
  bar.i

# update partial clone

  $ cd shallow
  $ hg update
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cat foo
  x
  $ cat bar
  y
  $ cd ..

# pull partial clone

  $ cd master
  $ echo a >> foo
  $ echo b >> bar
  $ hg commit -qm two
  $ cd ../shallow
  $ hg pull
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets a9688f18cb91
  (run 'hg update' to get a working copy)
  $ hg update
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cat foo
  x
  a
  $ cat bar
  y
  b

  $ cd ..