wireproto: don't expose legacy commands to version 2 of wire protocol

Now that we have the ability to control which transports a wire
protocol command is exposed on, let's put it to use.

We flag the "branches," "changegroup," and "changegroupsubset"
commands as only available on version 1. "branches" was used by the
legacy discovery mechanism and was replaced by the "known" and
"heads" commands. "changegroup" and "changegroupsubset" were
replaced by "getbundle."

"between" is also legacy. However, since it is used by the SSH
handshake protocol, marking it as legacy is a bit more complicated
and will be done in a later commit.

Another nuanced issue with this change is that the server-advertised
capabilities still list "changegroupsubset" despite the command not
being available. This will be addressed in a subsequent commit.

Differential Revision: https://phab.mercurial-scm.org/D2485

mercurial/wireproto.py

@@ -740,6 +740,8 b' def batch(repo, proto, cmds, others):'
 
     return bytesresponse(';'.join(res))
 
+# TODO mark as version 1 transport only once interaction with
+# SSH handshake mechanism is figured out.
 @wireprotocommand('between', 'pairs')
 def between(repo, proto, pairs):
     pairs = [decodelist(p, '-') for p in pairs.split(" ")]
@@ -760,7 +762,7 b' def branchmap(repo, proto):'
 
     return bytesresponse('\n'.join(heads))
 
-@wireprotocommand('branches', 'nodes')
+@wireprotocommand('branches', 'nodes', transportpolicy=POLICY_V1_ONLY)
 def branches(repo, proto, nodes):
     nodes = decodelist(nodes)
     r = []
@@ -835,7 +837,7 b' def _capabilities(repo, proto):'
 def capabilities(repo, proto):
     return bytesresponse(' '.join(_capabilities(repo, proto)))
 
-@wireprotocommand('changegroup', 'roots')
+@wireprotocommand('changegroup', 'roots', transportpolicy=POLICY_V1_ONLY)
 def changegroup(repo, proto, roots):
     nodes = decodelist(roots)
     outgoing = discovery.outgoing(repo, missingroots=nodes,
@@ -844,7 +846,8 b' def changegroup(repo, proto, roots):'
     gen = iter(lambda: cg.read(32768), '')
     return streamres(gen=gen)
 
-@wireprotocommand('changegroupsubset', 'bases heads')
+@wireprotocommand('changegroupsubset', 'bases heads',
+                  transportpolicy=POLICY_V1_ONLY)
 def changegroupsubset(repo, proto, bases, heads):
     bases = decodelist(bases)
     heads = decodelist(heads)

tests/test-ssh-proto.t

@@ -1273,6 +1273,33 b' Upgrade request must be followed by hell'
   e>     malformed handshake protocol: missing pairs 81\n
   e>     -\n
 
+Legacy commands are not exposed to version 2 of protocol
+
+  $ hg --config experimental.sshpeer.advertise-v2=true debugwireproto --localssh << EOF
+  > command branches
+  >     nodes 0000000000000000000000000000000000000000
+  > EOF
+  creating ssh peer from handshake results
+  sending branches command
+  response: 
+
+  $ hg --config experimental.sshpeer.advertise-v2=true debugwireproto --localssh << EOF
+  > command changegroup
+  >     roots 0000000000000000000000000000000000000000
+  > EOF
+  creating ssh peer from handshake results
+  sending changegroup command
+  response: 
+
+  $ hg --config experimental.sshpeer.advertise-v2=true debugwireproto --localssh << EOF
+  > command changegroupsubset
+  >     bases 0000000000000000000000000000000000000000
+  >     heads 0000000000000000000000000000000000000000
+  > EOF
+  creating ssh peer from handshake results
+  sending changegroupsubset command
+  response: 
+
   $ cd ..
 
 Test listkeys for listing namespaces