# HG changeset patch
# User Sune Foldager <cryo@cyanite.org>
# Date 1284541582 -7200
# Node ID d7fff529d85d7f8c2f6970031217ef6f418e3999
# Parent  3388ab21d768d87197d5eb1901f56c4ca23e6ea4
clone: only use stream when we understand the revlog format

This patch fixes issues with stream cloning in the presense of parentdelta,
lwcopy and similar additions that change the interpretation of the revlog
format, or the format itself.

Currently, the stream capability is sent like this:
stream=<version of changelog>

But the client doesn't actually check the version number; also, it only checks
the changelog and it doesn't capture the interpretation-changes and
flag-changes in parentdelta and lwcopy.

This patch removes the 'stream' capability whenever we use a non-basic revlog
format, to prevent old clients from receiving incorrect data. In those cases,
a new capability called 'streamreqs' is added instead. Instead of a revlog
version, it comes with a list of revlog-format relevant requirements, which
are a subset of the repository requirements, excluding things that are not
relevant for stream.

New clients use this to determine whether or not they can stream. Old clients
only look for the 'stream' capability, as always. New servers will still send
this when serving old repositories.

diff -r 3388ab21d768 -r d7fff529d85d mercurial/localrepo.py
--- a/mercurial/localrepo.py	Wed Sep 15 10:44:10 2010 +0200
+++ b/mercurial/localrepo.py	Wed Sep 15 11:06:22 2010 +0200
@@ -1784,7 +1784,7 @@
             return newheads - oldheads + 1
 
 
-    def stream_in(self, remote):
+    def stream_in(self, remote, requirements):
         fp = remote.stream_out()
         l = fp.readline()
         try:
@@ -1829,6 +1829,13 @@
         self.ui.status(_('transferred %s in %.1f seconds (%s/sec)\n') %
                        (util.bytecount(total_bytes), elapsed,
                         util.bytecount(total_bytes / elapsed)))
+
+        # new requirements = old non-format requirements + new format-related
+        # requirements from the streamed-in repository
+        requirements.update(set(self.requirements) - self.supportedformats)
+        self._applyrequirements(requirements)
+        self._writerequirements()
+
         self.invalidate()
         return len(self.heads()) + 1
 
@@ -1847,8 +1854,17 @@
         # and format flags on "stream" capability, and use
         # uncompressed only if compatible.
 
-        if stream and not heads and remote.capable('stream'):
-            return self.stream_in(remote)
+        if stream and not heads:
+            # 'stream' means remote revlog format is revlogv1 only
+            if remote.capable('stream'):
+                return self.stream_in(remote, set(('revlogv1',)))
+            # otherwise, 'streamreqs' contains the remote revlog format
+            streamreqs = remote.capable('streamreqs')
+            if streamreqs:
+                streamreqs = set(streamreqs.split(','))
+                # if we support it, stream in and adjust our requirements
+                if not streamreqs - self.supportedformats:
+                    return self.stream_in(remote, streamreqs)
         return self.pull(remote, heads)
 
     def pushkey(self, namespace, key, old, new):
diff -r 3388ab21d768 -r d7fff529d85d mercurial/wireproto.py
--- a/mercurial/wireproto.py	Wed Sep 15 10:44:10 2010 +0200
+++ b/mercurial/wireproto.py	Wed Sep 15 11:06:22 2010 +0200
@@ -172,7 +172,13 @@
 def capabilities(repo, proto):
     caps = 'lookup changegroupsubset branchmap pushkey'.split()
     if _allowstream(repo.ui):
-        caps.append('stream=%d' % repo.changelog.version)
+        requiredformats = repo.requirements & repo.supportedformats
+        # if our local revlogs are just revlogv1, add 'stream' cap
+        if not requiredformats - set(('revlogv1',)):
+            caps.append('stream')
+        # otherwise, add 'streamreqs' detailing our local revlog format
+        else:
+            caps.append('streamreqs=%s' % ','.join(requiredformats))
     caps.append('unbundle=%s' % ','.join(changegroupmod.bundlepriority))
     return ' '.join(caps)