diff mercurial/commands.py @ 14164:cb98fed52495

discovery: add new set-based discovery

Adds a new discovery method based on repeatedly sampling the still
undecided subset of the local node graph to determine the set of nodes
common to both the client and the server.

For small differences between client and server, it uses about the same
or slightly fewer roundtrips than the old tree-based discovery. For
larger differences, it typically reduces the number of roundtrips
drastically (from 150 to 4, for instance).

The old discovery code now lives in treediscovery.py, the new code is
in setdiscovery.py.

Still missing is a hook for extensions to contribute nodes to the
initial sample. For instance, Augie's remotebranches could contribute
the last known state of the server's heads.

Credits for the actual sampler and computing common heads instead of
bases go to Benoit Boissinot.

--- a/mercurial/commands.py	Mon May 02 19:21:30 2011 +0200
+++ b/mercurial/commands.py	Mon May 02 19:21:30 2011 +0200
@@ -15,6 +15,7 @@
 import merge as mergemod
 import minirst, revset, templatefilters
 import dagparser, context, simplemerge
+import random, setdiscovery, treediscovery, dagutil
 
 # Commands start here, listed alphabetically
 
@@ -1471,6 +1472,65 @@
     else:
         raise util.Abort(_("no ignore patterns found"))
 
+def debugdiscovery(ui, repo, remoteurl="default", **opts):
+    """runs the changeset discovery protocol in isolation"""
+    remoteurl, branches = hg.parseurl(ui.expandpath(remoteurl), opts.get('branch'))
+    remote = hg.repository(hg.remoteui(repo, opts), remoteurl)
+    ui.status(_('comparing with %s\n') % util.hidepassword(remoteurl))
+
+    # make sure tests are repeatable
+    random.seed(12323)
+
+    def doit(localheads, remoteheads):
+        if opts.get('old'):
+            if localheads:
+                raise util.Abort('cannot use localheads with old style discovery')
+            common, _in, hds = treediscovery.findcommonincoming(repo, remote,
+                                                                force=True)
+            common = set(common)
+            if not opts.get('nonheads'):
+                ui.write("unpruned common: %s\n" % " ".join([short(n)
+                                                            for n in common]))
+                dag = dagutil.revlogdag(repo.changelog)
+                all = dag.ancestorset(dag.internalizeall(common))
+                common = dag.externalizeall(dag.headsetofconnecteds(all))
+        else:
+            common, any, hds = setdiscovery.findcommonheads(ui, repo, remote)
+        common = set(common)
+        rheads = set(hds)
+        lheads = set(repo.heads())
+        ui.write("common heads: %s\n" % " ".join([short(n) for n in common]))
+        if lheads <= common:
+            ui.write("local is subset\n")
+        elif rheads <= common:
+            ui.write("remote is subset\n")
+
+    serverlogs = opts.get('serverlog')
+    if serverlogs:
+        for filename in serverlogs:
+            logfile = open(filename, 'r')
+            try:
+                line = logfile.readline()
+                while line:
+                    parts = line.strip().split(';')
+                    op = parts[1]
+                    if op == 'cg':
+                        pass
+                    elif op == 'cgss':
+                        doit(parts[2].split(' '), parts[3].split(' '))
+                    elif op == 'unb':
+                        doit(parts[3].split(' '), parts[2].split(' '))
+                    line = logfile.readline()
+            finally:
+                logfile.close()
+
+    else:
+        remoterevs, _checkout = hg.addbranchrevs(repo, remote, branches,
+                                                 opts.get('remote_head'))
+        localrevs = opts.get('local_head')
+        doit(localrevs, remoterevs)
+
+
 def debugindex(ui, repo, file_, **opts):
     """dump the contents of an index file"""
     r = None
@@ -4513,6 +4573,14 @@
          [('e', 'extended', None, _('try extended date formats'))],
          _('[-e] DATE [RANGE]')),
     "debugdata": (debugdata, [], _('FILE REV')),
+    "debugdiscovery": (debugdiscovery,
+         [('', 'old', None,
+           _('use old-style discovery')),
+          ('', 'nonheads', None,
+           _('use old-style discovery with non-heads included')),
+         ] + remoteopts,
+         _('[-l REV] [-r REV] [-b BRANCH]...'
+           ' [OTHER]')),
     "debugfsinfo": (debugfsinfo, [], _('[PATH]')),
     "debuggetbundle":
         (debuggetbundle,