narrow: refactor code around widening complicated by previous patch

Previous patch while adding support for using narrow_widen wireproto command,
complicated the code a bit. This patch refactors that.

Differential Revision: https://phab.mercurial-scm.org/D6437

hgext/narrow/narrowcommands.py

@@ -278,21 +278,22 def _widen(ui, repo, remote, commoninc,
     # silence the devel-warning of applying an empty changegroup
     overrides = {('devel', 'all-warnings'): False}
 
+    common = commoninc[0]
     with ui.uninterruptible():
-        common = commoninc[0]
         if ellipsesremote:
             ds = repo.dirstate
             p1, p2 = ds.p1(), ds.p2()
             with ds.parentchange():
                 ds.setparents(node.nullid, node.nullid)
+        if isoldellipses:
             with wrappedextraprepare:
-                if isoldellipses:
                     exchange.pull(repo, remote, heads=common)
                 else:
+            known = []
+            if ellipsesremote:
                     known = [node.hex(ctx.node()) for ctx in
                                        repo.set('::%ln', common)
                                        if ctx.node() != node.nullid]
-
                     with remote.commandexecutor() as e:
                         bundle = e.callcommand('narrow_widen', {
                             'oldincludes': oldincludes,
@@ -302,35 +303,19 def _widen(ui, repo, remote, commoninc,
                             'cgversion': '03',
                             'commonheads': common,
                             'known': known,
-                            'ellipses': True,
+                    'ellipses': ellipsesremote,
                         }).result()
-                    trmanager = exchange.transactionmanager(repo, 'widen',
-                                                            remote.url())
-                    with trmanager:
-                        op = bundle2.bundleoperation(repo,
-                                trmanager.transaction, source='widen')
+
+            trmanager = exchange.transactionmanager(repo, 'widen', remote.url())
+            with trmanager, repo.ui.configoverride(overrides, 'widen'):
+                op = bundle2.bundleoperation(repo, trmanager.transaction,
+                                             source='widen')
+                # TODO: we should catch error.Abort here
                         bundle2.processbundle(repo, bundle, op=op)
 
+        if ellipsesremote:
             with ds.parentchange():
                 ds.setparents(p1, p2)
-        else:
-            with remote.commandexecutor() as e:
-                bundle = e.callcommand('narrow_widen', {
-                    'oldincludes': oldincludes,
-                    'oldexcludes': oldexcludes,
-                    'newincludes': newincludes,
-                    'newexcludes': newexcludes,
-                    'cgversion': '03',
-                    'commonheads': common,
-                    'known': [],
-                    'ellipses': False,
-                }).result()
-
-            with repo.transaction('widening') as tr:
-                with repo.ui.configoverride(overrides, 'widen'):
-                    tgetter = lambda: tr
-                    bundle2.processbundle(repo, bundle,
-                            transactiongetter=tgetter)
 
         with repo.transaction('widening'):
             repo.setnewnarrowpats()