view tests/test-bundle2-remote-changegroup.t @ 26623:5a95fe44121d

clonebundles: support for seeding clones from pre-generated bundles

Cloning can be an expensive operation for servers because the server
generates a bundle from existing repository data at request time. For
a large repository like mozilla-central, this consumes 4+ minutes
of CPU time on the server. It also results in significant network
utilization. Multiplied by hundreds or even thousands of clients and
the ensuing load can result in difficulties scaling the Mercurial server.

Despite generation of bundles being deterministic until the next
changeset is added, the generation of bundles to service a clone request
is not cached. Each clone thus performs redundant work. This is
wasteful.

This patch introduces the "clonebundles" extension and related
client-side functionality to help alleviate this deficiency. The
client-side feature is behind an experimental flag and is not enabled by
default.

It works as follows:

1) Server operator generates a bundle and makes it available on a
   server (likely HTTP).
2) Server operator defines the URL of a bundle file in a
   .hg/clonebundles.manifest file.
3) Client `hg clone`ing sees the server is advertising bundle URLs.
4) Client fetches and applies the advertised bundle.
5) Client performs equivalent of `hg pull` to fetch changes made since
   the bundle was created.

Essentially, the server performs the expensive work of generating a
bundle once and all subsequent clones fetch a static file from
somewhere. Scaling static file serving is a much more manageable
problem than scaling a Python application like Mercurial. Assuming your
repository grows less than 1% per day, the end result is 99+% of CPU
and network load from clones is eliminated, allowing Mercurial servers
to scale more easily. Serving static files also means data can be
transferred to clients as fast as they can consume it, rather than as
fast as servers can generate it. This makes clones faster.

Mozilla has implemented similar functionality of this patch on
hg.mozilla.org using a custom extension. We are hosting bundle files in
Amazon S3 and CloudFront (a CDN) and have successfully offloaded
>1 TB/day in data transfer from hg.mozilla.org, freeing up significant
bandwidth and CPU resources. The positive impact has been stellar and
I believe it has proved its value to be included in Mercurial core. I
feel it is important for the client-side support to be enabled in core
by default because it means that clients will get faster, more reliable
clones and will enable server operators to reduce load without
requiring any client-side configuration changes (assuming clients are
up to date, of course).

The scope of this feature is narrowly and specifically tailored to
cloning, despite "serve pulls from pre-generated bundles" being a valid
and useful feature. I would eventually like for Mercurial servers to
support transferring *all* repository data via statically hosted files.
You could imagine a server that siphons all pushed data to bundle files
and instructs clients to apply a stream of bundles to reconstruct all
repository data. This feature, while useful and powerful, is
significantly more work to implement because it requires the server
component have awareness of discovery and a mapping of which changesets
are in which files. Full, clone bundles, by contrast, are much simpler.

The wire protocol command is named "clonebundles" instead of something
more generic like "staticbundles" to leave the door open for a new, more
powerful and more generic server-side component with minimal backwards
compatibility implications. The name "bundleclone" is used by Mozilla's
extension and would cause problems since there are subtle differences
in Mozilla's extension.

Mozilla's experience with this idea has taught us that some form of
"content negotiation" is required. Not all clients will support all
bundle formats or even URLs (advanced TLS requirements, etc). To ensure
the highest uptake possible, a server needs to advertise multiple
versions of bundles and clients need to be able to choose the most
appropriate from that list one. The "attributes" in each
server-advertised entry facilitate this filtering and sorting. Their
use will become apparent in subsequent patches.

Initial inspiration and credit for the idea of cloning from static files
belongs to Augie Fackler and his "lookaside clone" extension proof of
concept.

#require killdaemons

Create an extension to test bundle2 remote-changegroup parts

  $ cat > bundle2.py << EOF
  > """A small extension to test bundle2 remote-changegroup parts.
  > 
  > Current bundle2 implementation doesn't provide a way to generate those
  > parts, so they must be created by extensions.
  > """
  > from mercurial import bundle2, changegroup, exchange, util
  > 
  > def _getbundlechangegrouppart(bundler, repo, source, bundlecaps=None,
  >                               b2caps=None, heads=None, common=None,
  >                               **kwargs):
  >     """this function replaces the changegroup part handler for getbundle.
  >     It allows to create a set of arbitrary parts containing changegroups
  >     and remote-changegroups, as described in a bundle2maker file in the
  >     repository .hg/ directory.
  > 
  >     Each line of that bundle2maker file contain a description of the
  >     part to add:
  >       - changegroup common_revset heads_revset
  >           Creates a changegroup part based, using common_revset and
  >           heads_revset for changegroup.getchangegroup.
  >       - remote-changegroup url file
  >           Creates a remote-changegroup part for a bundle at the given
  >           url. Size and digest, as required by the client, are computed
  >           from the given file.
  >       - raw-remote-changegroup <python expression>
  >           Creates a remote-changegroup part with the data given in the
  >           python expression as parameters. The python expression is
  >           evaluated with eval, and is expected to be a dict.
  >     """
  >     def newpart(name, data=''):
  >         """wrapper around bundler.newpart adding an extra part making the
  >         client output information about each processed part"""
  >         bundler.newpart('output', data=name)
  >         part = bundler.newpart(name, data=data)
  >         return part
  > 
  >     for line in open(repo.join('bundle2maker'), 'r'):
  >         line = line.strip()
  >         try:
  >             verb, args = line.split(None, 1)
  >         except ValueError:
  >             verb, args = line, ''
  >         if verb == 'remote-changegroup':
  >            url, file = args.split()
  >            bundledata = open(file, 'rb').read()
  >            digest = util.digester.preferred(b2caps['digests'])
  >            d = util.digester([digest], bundledata)
  >            part = newpart('remote-changegroup')
  >            part.addparam('url', url)
  >            part.addparam('size', str(len(bundledata)))
  >            part.addparam('digests', digest)
  >            part.addparam('digest:%s' % digest, d[digest])
  >         elif verb == 'raw-remote-changegroup':
  >            part = newpart('remote-changegroup')
  >            for k, v in eval(args).items():
  >                part.addparam(k, str(v))
  >         elif verb == 'changegroup':
  >             _common, heads = args.split()
  >             common.extend(repo.lookup(r) for r in repo.revs(_common))
  >             heads = [repo.lookup(r) for r in repo.revs(heads)]
  >             cg = changegroup.getchangegroup(repo, 'changegroup',
  >                 heads=heads, common=common)
  >             newpart('changegroup', cg.getchunks())
  >         else:
  >             raise Exception('unknown verb')
  > 
  > exchange.getbundle2partsmapping['changegroup'] = _getbundlechangegrouppart
  > EOF

Start a simple HTTP server to serve bundles

  $ python "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid
  $ cat dumb.pid >> $DAEMON_PIDS

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > bundle2-exp=True
  > [ui]
  > ssh=python "$TESTDIR/dummyssh"
  > logtemplate={rev}:{node|short} {phase} {author} {bookmarks} {desc|firstline}
  > EOF

  $ hg init repo

  $ hg -R repo unbundle $TESTDIR/bundles/rebase.hg
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)

  $ hg -R repo log -G
  o  7:02de42196ebe draft Nicolas Dumazet <[e-mail]>  H
  |
  | o  6:eea13746799a draft Nicolas Dumazet <[e-mail]>  G
  |/|
  o |  5:24b6387c8c8c draft Nicolas Dumazet <[e-mail]>  F
  | |
  | o  4:9520eea781bc draft Nicolas Dumazet <[e-mail]>  E
  |/
  | o  3:32af7686d403 draft Nicolas Dumazet <[e-mail]>  D
  | |
  | o  2:5fddd98957c8 draft Nicolas Dumazet <[e-mail]>  C
  | |
  | o  1:42ccdea3bb16 draft Nicolas Dumazet <[e-mail]>  B
  |/
  o  0:cd010b8cd998 draft Nicolas Dumazet <[e-mail]>  A
  
  $ hg clone repo orig
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cat > repo/.hg/hgrc << EOF
  > [extensions]
  > bundle2=$TESTTMP/bundle2.py
  > EOF

Test a pull with an remote-changegroup

  $ hg bundle -R repo --base '0:4' -r '5:7' bundle.hg
  3 changesets found
  $ cat > repo/.hg/bundle2maker << EOF
  > remote-changegroup http://localhost:$HGPORT/bundle.hg bundle.hg
  > EOF
  $ hg clone orig clone -r 3 -r 4
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 5 files (+1 heads)
  updating to branch default
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 2 changes to 2 files (+1 heads)
  (run 'hg heads .' to see heads, 'hg merge' to merge)
  $ hg -R clone log -G
  o  7:02de42196ebe public Nicolas Dumazet <[e-mail]>  H
  |
  | o  6:eea13746799a public Nicolas Dumazet <[e-mail]>  G
  |/|
  o |  5:24b6387c8c8c public Nicolas Dumazet <[e-mail]>  F
  | |
  | o  4:9520eea781bc public Nicolas Dumazet <[e-mail]>  E
  |/
  | @  3:32af7686d403 public Nicolas Dumazet <[e-mail]>  D
  | |
  | o  2:5fddd98957c8 public Nicolas Dumazet <[e-mail]>  C
  | |
  | o  1:42ccdea3bb16 public Nicolas Dumazet <[e-mail]>  B
  |/
  o  0:cd010b8cd998 public Nicolas Dumazet <[e-mail]>  A
  
  $ rm -rf clone

Test a pull with an remote-changegroup and a following changegroup

  $ hg bundle -R repo --base 2 -r '3:4' bundle2.hg
  2 changesets found
  $ cat > repo/.hg/bundle2maker << EOF
  > remote-changegroup http://localhost:$HGPORT/bundle2.hg bundle2.hg
  > changegroup 0:4 5:7
  > EOF
  $ hg clone orig clone -r 2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 3 files
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  remote: changegroup
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 2 changes to 2 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg -R clone log -G
  o  7:02de42196ebe public Nicolas Dumazet <[e-mail]>  H
  |
  | o  6:eea13746799a public Nicolas Dumazet <[e-mail]>  G
  |/|
  o |  5:24b6387c8c8c public Nicolas Dumazet <[e-mail]>  F
  | |
  | o  4:9520eea781bc public Nicolas Dumazet <[e-mail]>  E
  |/
  | o  3:32af7686d403 public Nicolas Dumazet <[e-mail]>  D
  | |
  | @  2:5fddd98957c8 public Nicolas Dumazet <[e-mail]>  C
  | |
  | o  1:42ccdea3bb16 public Nicolas Dumazet <[e-mail]>  B
  |/
  o  0:cd010b8cd998 public Nicolas Dumazet <[e-mail]>  A
  
  $ rm -rf clone

Test a pull with a changegroup followed by an remote-changegroup

  $ hg bundle -R repo --base '0:4' -r '5:7' bundle3.hg
  3 changesets found
  $ cat > repo/.hg/bundle2maker << EOF
  > changegroup 000000000000 :4
  > remote-changegroup http://localhost:$HGPORT/bundle3.hg bundle3.hg
  > EOF
  $ hg clone orig clone -r 2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 3 files
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: changegroup
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 2 changes to 2 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg -R clone log -G
  o  7:02de42196ebe public Nicolas Dumazet <[e-mail]>  H
  |
  | o  6:eea13746799a public Nicolas Dumazet <[e-mail]>  G
  |/|
  o |  5:24b6387c8c8c public Nicolas Dumazet <[e-mail]>  F
  | |
  | o  4:9520eea781bc public Nicolas Dumazet <[e-mail]>  E
  |/
  | o  3:32af7686d403 public Nicolas Dumazet <[e-mail]>  D
  | |
  | @  2:5fddd98957c8 public Nicolas Dumazet <[e-mail]>  C
  | |
  | o  1:42ccdea3bb16 public Nicolas Dumazet <[e-mail]>  B
  |/
  o  0:cd010b8cd998 public Nicolas Dumazet <[e-mail]>  A
  
  $ rm -rf clone

Test a pull with two remote-changegroups and a changegroup

  $ hg bundle -R repo --base 2 -r '3:4' bundle4.hg
  2 changesets found
  $ hg bundle -R repo --base '3:4' -r '5:6' bundle5.hg
  2 changesets found
  $ cat > repo/.hg/bundle2maker << EOF
  > remote-changegroup http://localhost:$HGPORT/bundle4.hg bundle4.hg
  > remote-changegroup http://localhost:$HGPORT/bundle5.hg bundle5.hg
  > changegroup 0:6 7
  > EOF
  $ hg clone orig clone -r 2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 3 files
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 1 changes to 1 files
  remote: changegroup
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg -R clone log -G
  o  7:02de42196ebe public Nicolas Dumazet <[e-mail]>  H
  |
  | o  6:eea13746799a public Nicolas Dumazet <[e-mail]>  G
  |/|
  o |  5:24b6387c8c8c public Nicolas Dumazet <[e-mail]>  F
  | |
  | o  4:9520eea781bc public Nicolas Dumazet <[e-mail]>  E
  |/
  | o  3:32af7686d403 public Nicolas Dumazet <[e-mail]>  D
  | |
  | @  2:5fddd98957c8 public Nicolas Dumazet <[e-mail]>  C
  | |
  | o  1:42ccdea3bb16 public Nicolas Dumazet <[e-mail]>  B
  |/
  o  0:cd010b8cd998 public Nicolas Dumazet <[e-mail]>  A
  
  $ rm -rf clone

Hash digest tests

  $ hg bundle -R repo -a bundle6.hg
  8 changesets found

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle6.hg', 'size': 1663, 'digests': 'sha1', 'digest:sha1': '2c880cfec23cff7d8f80c2f12958d1563cbdaba6'}
  > EOF
  $ hg clone ssh://user@dummy/repo clone
  requesting all changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf clone

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle6.hg', 'size': 1663, 'digests': 'md5', 'digest:md5': 'e22172c2907ef88794b7bea6642c2394'}
  > EOF
  $ hg clone ssh://user@dummy/repo clone
  requesting all changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf clone

Hash digest mismatch throws an error

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle6.hg', 'size': 1663, 'digests': 'sha1', 'digest:sha1': '0' * 40}
  > EOF
  $ hg clone ssh://user@dummy/repo clone
  requesting all changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  transaction abort!
  rollback completed
  abort: bundle at http://localhost:$HGPORT/bundle6.hg is corrupted:
  sha1 mismatch: expected 0000000000000000000000000000000000000000, got 2c880cfec23cff7d8f80c2f12958d1563cbdaba6
  [255]

Multiple hash digests can be given

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle6.hg', 'size': 1663, 'digests': 'md5 sha1', 'digest:md5': 'e22172c2907ef88794b7bea6642c2394', 'digest:sha1': '2c880cfec23cff7d8f80c2f12958d1563cbdaba6'}
  > EOF
  $ hg clone ssh://user@dummy/repo clone
  requesting all changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm -rf clone

If either of the multiple hash digests mismatches, an error is thrown

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle6.hg', 'size': 1663, 'digests': 'md5 sha1', 'digest:md5': '0' * 32, 'digest:sha1': '2c880cfec23cff7d8f80c2f12958d1563cbdaba6'}
  > EOF
  $ hg clone ssh://user@dummy/repo clone
  requesting all changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  transaction abort!
  rollback completed
  abort: bundle at http://localhost:$HGPORT/bundle6.hg is corrupted:
  md5 mismatch: expected 00000000000000000000000000000000, got e22172c2907ef88794b7bea6642c2394
  [255]

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle6.hg', 'size': 1663, 'digests': 'md5 sha1', 'digest:md5': 'e22172c2907ef88794b7bea6642c2394', 'digest:sha1': '0' * 40}
  > EOF
  $ hg clone ssh://user@dummy/repo clone
  requesting all changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  transaction abort!
  rollback completed
  abort: bundle at http://localhost:$HGPORT/bundle6.hg is corrupted:
  sha1 mismatch: expected 0000000000000000000000000000000000000000, got 2c880cfec23cff7d8f80c2f12958d1563cbdaba6
  [255]

Corruption tests

  $ hg clone orig clone -r 2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 3 files
  updating to branch default
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cat > repo/.hg/bundle2maker << EOF
  > remote-changegroup http://localhost:$HGPORT/bundle4.hg bundle4.hg
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle5.hg', 'size': 578, 'digests': 'sha1', 'digest:sha1': '0' * 40}
  > changegroup 0:6 7
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 1 changes to 1 files
  transaction abort!
  rollback completed
  abort: bundle at http://localhost:$HGPORT/bundle5.hg is corrupted:
  sha1 mismatch: expected 0000000000000000000000000000000000000000, got f29485d6bfd37db99983cfc95ecb52f8ca396106
  [255]

The entire transaction has been rolled back in the pull above

  $ hg -R clone log -G
  @  2:5fddd98957c8 public Nicolas Dumazet <[e-mail]>  C
  |
  o  1:42ccdea3bb16 public Nicolas Dumazet <[e-mail]>  B
  |
  o  0:cd010b8cd998 public Nicolas Dumazet <[e-mail]>  A
  

No params

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {}
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: remote-changegroup: missing "url" param
  [255]

Missing size

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle4.hg'}
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: remote-changegroup: missing "size" param
  [255]

Invalid size

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle4.hg', 'size': 'foo'}
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: remote-changegroup: invalid value for param "size"
  [255]

Size mismatch

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle4.hg', 'size': 42}
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  transaction abort!
  rollback completed
  abort: bundle at http://localhost:$HGPORT/bundle4.hg is corrupted:
  size mismatch: expected 42, got 581
  [255]

Unknown digest

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle4.hg', 'size': 581, 'digests': 'foo', 'digest:foo': 'bar'}
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: missing support for remote-changegroup - digest:foo
  [255]

Missing digest

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'http://localhost:$HGPORT/bundle4.hg', 'size': 581, 'digests': 'sha1'}
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: remote-changegroup: missing "digest:sha1" param
  [255]

Not an HTTP url

  $ cat > repo/.hg/bundle2maker << EOF
  > raw-remote-changegroup {'url': 'ssh://localhost:$HGPORT/bundle4.hg', 'size': 581}
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: remote-changegroup does not support ssh urls
  [255]

Not a bundle

  $ cat > notbundle.hg << EOF
  > foo
  > EOF
  $ cat > repo/.hg/bundle2maker << EOF
  > remote-changegroup http://localhost:$HGPORT/notbundle.hg notbundle.hg
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: http://localhost:$HGPORT/notbundle.hg: not a Mercurial bundle
  [255]

Not a bundle 1.0

  $ cat > notbundle10.hg << EOF
  > HG20
  > EOF
  $ cat > repo/.hg/bundle2maker << EOF
  > remote-changegroup http://localhost:$HGPORT/notbundle10.hg notbundle10.hg
  > EOF
  $ hg pull -R clone ssh://user@dummy/repo
  pulling from ssh://user@dummy/repo
  searching for changes
  remote: remote-changegroup
  abort: http://localhost:$HGPORT/notbundle10.hg: not a bundle version 1.0
  [255]

  $ hg -R clone log -G
  @  2:5fddd98957c8 public Nicolas Dumazet <[e-mail]>  C
  |
  o  1:42ccdea3bb16 public Nicolas Dumazet <[e-mail]>  B
  |
  o  0:cd010b8cd998 public Nicolas Dumazet <[e-mail]>  A
  
  $ rm -rf clone

  $ killdaemons.py