commands: support creating stream clone bundles

Now that we have support for recognizing the streaming clone bundle
type, add a debug command for creating them.

I decided to create a new debug command instead of adding support to `hg
bundle` because stream clone bundles are not exactly used the same way
as normal bundle files and I don't want to commit to supporting them
through the official `hg bundle` command forever. A debug command,
however, can be changed without as much concern for backwards
compatibility.

As part of this, `hg bundle` will explicitly reject requests to produce
stream bundles.

This command will be required by server operators using stream clone
bundles with the clone bundles feature.

mercurial/commands.py

@@ -23,6 +23,7 b' import random, operator'
 import setdiscovery, treediscovery, dagutil, pvec, localrepo, destutil
 import phases, obsolete, exchange, bundle2, repair, lock as lockmod
 import ui as uimod
+import streamclone
 
 table = {}
 
@@ -1250,6 +1251,11 b' def bundle(ui, repo, fname, dest=None, *'
                           hint=_('see "hg help bundle" for supported '
                                  'values for --type'))
 
+    # Packed bundles are a pseudo bundle format for now.
+    if cgversion == 's1':
+        raise error.Abort(_('packed bundles cannot be produced by "hg bundle"'),
+                          hint=_('use "hg debugcreatestreamclonebundle"'))
+
     if opts.get('all'):
         base = ['null']
     else:
@@ -1960,6 +1966,18 b' def _debugbundle2(ui, gen, **opts):'
                 ui.write("    %s\n" % hex(node))
                 chain = node
 
+@command('debugcreatestreamclonebundle', [], 'FILE')
+def debugcreatestreamclonebundle(ui, repo, fname):
+    """create a stream clone bundle file
+
+    Stream bundles are special bundles that are essentially archives of
+    revlog files. They are commonly used for cloning very quickly.
+    """
+    requirements, gen = streamclone.generatebundlev1(repo)
+    changegroup.writechunks(ui, gen, fname)
+
+    ui.write(_('bundle requirements: %s\n') % ', '.join(sorted(requirements)))
+
 @command('debugcheckstate', [], '')
 def debugcheckstate(ui, repo):
     """validate the correctness of the current dirstate"""

tests/test-bundle.t

@@ -250,6 +250,44 b' Pull full.hg into empty again (using -R;'
   changegroup hook: HG_NODE=f9ee2f85a263049e9ae6d37a0e67e96194ffb735 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=bundle:empty+full.hg (glob)
   (run 'hg heads' to see heads, 'hg merge' to merge)
 
+Cannot produce streaming clone bundles with "hg bundle"
+
+  $ hg -R test bundle -t packed1 packed.hg
+  abort: packed bundles cannot be produced by "hg bundle"
+  (use "hg debugcreatestreamclonebundle")
+  [255]
+
+packed1 is produced properly
+
+  $ hg -R test debugcreatestreamclonebundle packed.hg
+  writing 2608 bytes for 6 files
+  bundle requirements: revlogv1
+
+  $ f -B 64 --size --sha1 --hexdump packed.hg
+  packed.hg: size=2758, sha1=864c1c7b490bac9f2950ef5a660668378ac0524e
+  0000: 48 47 53 31 55 4e 00 00 00 00 00 00 00 06 00 00 |HGS1UN..........|
+  0010: 00 00 00 00 0a 30 00 09 72 65 76 6c 6f 67 76 31 |.....0..revlogv1|
+  0020: 00 64 61 74 61 2f 61 64 69 66 66 65 72 65 6e 74 |.data/adifferent|
+  0030: 66 69 6c 65 2e 69 00 31 33 39 0a 00 01 00 01 00 |file.i.139......|
+
+generaldelta requirement is listed in stream clone bundles
+
+  $ hg --config format.generaldelta=true init testgd
+  $ cd testgd
+  $ touch foo
+  $ hg -q commit -A -m initial
+  $ cd ..
+  $ hg -R testgd debugcreatestreamclonebundle packedgd.hg
+  writing 301 bytes for 3 files
+  bundle requirements: generaldelta, revlogv1
+
+  $ f -B 64 --size --sha1 --hexdump packedgd.hg
+  packedgd.hg: size=396, sha1=981f9e589799335304a5a9a44caa3623a48d2a9f
+  0000: 48 47 53 31 55 4e 00 00 00 00 00 00 00 03 00 00 |HGS1UN..........|
+  0010: 00 00 00 00 01 2d 00 16 67 65 6e 65 72 61 6c 64 |.....-..generald|
+  0020: 65 6c 74 61 2c 72 65 76 6c 6f 67 76 31 00 64 61 |elta,revlogv1.da|
+  0030: 74 61 2f 66 6f 6f 2e 69 00 36 34 0a 00 03 00 01 |ta/foo.i.64.....|
+
 Create partial clones
 
   $ rm -r empty

tests/test-completion.t

@@ -75,6 +75,7 b' Show debug commands if there are no othe'
   debugcommands
   debugcomplete
   debugconfig
+  debugcreatestreamclonebundle
   debugdag
   debugdata
   debugdate
@@ -236,6 +237,7 b' Show all commands + options'
   debugcheckstate: 
   debugcommands: 
   debugcomplete: options
+  debugcreatestreamclonebundle: 
   debugdag: tags, branches, dots, spaces
   debugdata: changelog, manifest, dir
   debugdate: extended

tests/test-help.t

@@ -791,6 +791,8 b' Test list of internal help commands'
                  list all available commands and options
    debugcomplete
                  returns the completion list associated with the given command
+   debugcreatestreamclonebundle
+                 create a stream clone bundle file
    debugdag      format the changelog or an index DAG as a concise textual
                  description
    debugdata     dump the contents of a data file revision
@@ -1066,6 +1068,7 b' Test keyword search help'
   
    bookmarks create a new bookmark or list existing bookmarks
    clone     make a copy of an existing repository
+   debugcreatestreamclonebundle create a stream clone bundle file
    paths     show aliases for remote repositories
    update    update working directory (or switch revisions)