tests/test-clone-uncompressed.t

bundle2: store changeset count when creating file bundles

The bundle2 changegroup part has an advisory param saying how many
changesets are in the part. Before this patch, we were setting
this part when generating bundle2 parts via the wire protocol but
not when generating local bundle2 files.

A side effect of not setting the changeset count part is that progress
bars don't work when applying changesets. As the tests show, this
impacted clone bundles, shelve, backup bundles, `hg unbundle`, and
anything touching bundle2 files.

This patch adds a backdoor to allow us to pass state from
changegroup generation into the unbundler. We store the number
of changesets in the changegroup in this state and use it to
populate the aforementioned advisory part parameter when generating
the bundle2 bundle.

I concede that I'm not thrilled by how state is being passed in
changegroup.py (it feels a bit hacky). I would love to overhaul the
rather confusing set of functions in changegroup.py with something that
passes rich objects around instead of e.g. low-level generators.
However, given the code freeze for 3.9 is imminent, I'd rather not
undertake this endeavor right now. This feels like the easiest way
to get the parameter added to the changegroup part.

#require serve

Initialize repository
the status call is to check for issue5130

  $ hg init server
  $ cd server
  $ touch foo
  $ hg -q commit -A -m initial
  >>> for i in range(1024):
  ...     with open(str(i), 'wb') as fh:
  ...         fh.write(str(i))
  $ hg -q commit -A -m 'add a lot of files'
  $ hg st
  $ hg serve -p $HGPORT -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ cd ..

Basic clone

  $ hg clone --uncompressed -U http://localhost:$HGPORT clone1
  streaming all changes
  1027 files to transfer, 96.3 KB of data
  transferred 96.3 KB in * seconds (*/sec) (glob)
  searching for changes
  no changes found

Clone with background file closing enabled

  $ hg --debug --config worker.backgroundclose=true --config worker.backgroundcloseminfilecount=1 clone --uncompressed -U http://localhost:$HGPORT clone-background | grep -v adding
  using http://localhost:$HGPORT/
  sending capabilities command
  sending branchmap command
  streaming all changes
  sending stream_out command
  1027 files to transfer, 96.3 KB of data
  starting 4 threads for background file closing
  transferred 96.3 KB in * seconds (*/sec) (glob)
  query 1; heads
  sending batch command
  searching for changes
  all remote heads known locally
  no changes found
  sending getbundle command
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-part: total payload size 58
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-bundle: 1 parts total
  checking for updated bookmarks


Stream clone while repo is changing:

  $ mkdir changing
  $ cd changing

extension for delaying the server process so we reliably can modify the repo
while cloning

  $ cat > delayer.py <<EOF
  > import time
  > from mercurial import extensions, scmutil
  > def __call__(orig, self, path, *args, **kwargs):
  >     if path == 'data/f1.i':
  >         time.sleep(2)
  >     return orig(self, path, *args, **kwargs)
  > extensions.wrapfunction(scmutil.vfs, '__call__', __call__)
  > EOF

prepare repo with small and big file to cover both code paths in emitrevlogdata

  $ hg init repo
  $ touch repo/f1
  $ $TESTDIR/seq.py 50000 > repo/f2
  $ hg -R repo ci -Aqm "0"
  $ hg -R repo serve -p $HGPORT1 -d --pid-file=hg.pid --config extensions.delayer=delayer.py
  $ cat hg.pid >> $DAEMON_PIDS

clone while modifying the repo between stating file with write lock and
actually serving file content

  $ hg clone -q --uncompressed -U http://localhost:$HGPORT1 clone &
  $ sleep 1
  $ echo >> repo/f1
  $ echo >> repo/f2
  $ hg -R repo ci -m "1"
  $ wait
  $ hg -R clone id
  000000000000