--- a/mercurial/wireproto.py	Mon Apr 16 22:00:52 2018 -0700
+++ b/mercurial/wireproto.py	Mon Apr 16 22:08:13 2018 -0700
@@ -114,55 +114,6 @@
 
     return ui.configbool('server', 'bundle1')
 
-def supportedcompengines(ui, role):
-    """Obtain the list of supported compression engines for a request."""
-    assert role in (util.CLIENTROLE, util.SERVERROLE)
-
-    compengines = util.compengines.supportedwireengines(role)
-
-    # Allow config to override default list and ordering.
-    if role == util.SERVERROLE:
-        configengines = ui.configlist('server', 'compressionengines')
-        config = 'server.compressionengines'
-    else:
-        # This is currently implemented mainly to facilitate testing. In most
-        # cases, the server should be in charge of choosing a compression engine
-        # because a server has the most to lose from a sub-optimal choice. (e.g.
-        # CPU DoS due to an expensive engine or a network DoS due to poor
-        # compression ratio).
-        configengines = ui.configlist('experimental',
-                                      'clientcompressionengines')
-        config = 'experimental.clientcompressionengines'
-
-    # No explicit config. Filter out the ones that aren't supposed to be
-    # advertised and return default ordering.
-    if not configengines:
-        attr = 'serverpriority' if role == util.SERVERROLE else 'clientpriority'
-        return [e for e in compengines
-                if getattr(e.wireprotosupport(), attr) > 0]
-
-    # If compression engines are listed in the config, assume there is a good
-    # reason for it (like server operators wanting to achieve specific
-    # performance characteristics). So fail fast if the config references
-    # unusable compression engines.
-    validnames = set(e.name() for e in compengines)
-    invalidnames = set(e for e in configengines if e not in validnames)
-    if invalidnames:
-        raise error.Abort(_('invalid compression engine defined in %s: %s') %
-                          (config, ', '.join(sorted(invalidnames))))
-
-    compengines = [e for e in compengines if e.name() in configengines]
-    compengines = sorted(compengines,
-                         key=lambda e: configengines.index(e.name()))
-
-    if not compengines:
-        raise error.Abort(_('%s config option does not specify any known '
-                            'compression engines') % config,
-                          hint=_('usable compression engines: %s') %
-                          ', '.sorted(validnames))
-
-    return compengines
-
 # For version 1 transports.
 commands = wireprototypes.commanddict()