synchronize: Fix (delegated) local rsync

Makes delegated local rsync work even if ansible_host or ansible_ssh_host is set.
Makes local rsync work when no ssh is installed.

lib/ansible/modules/files/synchronize.py

@@ -347,6 +347,14 @@ def substitute_controller(path):
     return path
 
 
+def is_rsh_needed(source, dest):
+    if source.startswith('rsync://') or dest.startswith('rsync://'):
+        return False
+    if ':' in source or ':' in dest:
+        return True
+    return False
+
+
 def main():
     module = AnsibleModule(
         argument_spec = dict(
@@ -465,7 +473,7 @@ def main():
     if source.startswith('rsync://') and dest.startswith('rsync://'):
         module.fail_json(msg='either src or dest must be a localhost', rc=1)
 
-    if not source.startswith('rsync://') and not dest.startswith('rsync://'):
+    if is_rsh_needed(source, dest):
         ssh_cmd = [module.get_bin_path('ssh', required=True), '-S', 'none']
         if private_key is not None:
             ssh_cmd.extend(['-i', private_key])

lib/ansible/plugins/action/synchronize.py

@@ -216,6 +216,11 @@ class ActionModule(ActionBase):
         except KeyError:
             dest_host = dest_host_inventory_vars.get('ansible_ssh_host', inventory_hostname)
 
+        dest_host_ids = [hostid for hostid in (dest_host_inventory_vars.get('inventory_hostname'),
+                                               dest_host_inventory_vars.get('ansible_host'),
+                                               dest_host_inventory_vars.get('ansible_ssh_host'))
+                         if hostid is not None]
+
         localhost_ports = set()
         for host in C.LOCALHOST:
             localhost_vars = task_vars['hostvars'].get(host, {})
@@ -231,9 +236,9 @@ class ActionModule(ActionBase):
         # host rsync puts the files on.  This is about *rsync's connection*,
         # not about the ansible connection to run the module.
         dest_is_local = False
-        if not delegate_to and remote_transport is False:
+        if delegate_to is None and remote_transport is False:
             dest_is_local = True
-        elif delegate_to and delegate_to == dest_host:
+        elif delegate_to is not None and delegate_to in dest_host_ids:
             dest_is_local = True
 
         # CHECK FOR NON-DEFAULT SSH PORT
@@ -245,7 +250,7 @@ class ActionModule(ActionBase):
         # Set use_delegate if we are going to run rsync on a delegated host
         # instead of localhost
         use_delegate = False
-        if dest_host == delegate_to:
+        if delegate_to is not None and delegate_to in dest_host_ids:
             # edge case: explicit delegate and dest_host are the same
             # so we run rsync on the remote machine targeting its localhost
             # (itself)