codereview: force hg update after hg pull -u during hg sync

If you hg update your client to an earlier CL, then
hg sync will move you back to tip if it pulls anything in,
but it will leave you where you are if it doesn't pull anything in.
That's confusing: make hg sync always update to tip.

R=golang-dev, bradfitz, r, dsymonds
CC=golang-dev
https://golang.org/cl/10456044

lib/codereview/codereview.py

@@ -1168,6 +1168,25 @@ def hg_pull(ui, repo, **opts):
 		ui.write(line + '\n')
 	return err
 
+def hg_update(ui, repo, **opts):
+	w = uiwrap(ui)
+	ui.quiet = False
+	ui.verbose = True  # for file list
+	err = hg_commands.update(ui, repo, **opts)
+	for line in w.output().split('\n'):
+		if isNoise(line):
+			continue
+		if line.startswith('moving '):
+			line = 'mv ' + line[len('moving '):]
+		if line.startswith('getting ') and line.find(' to ') >= 0:
+			line = 'mv ' + line[len('getting '):]
+		if line.startswith('getting '):
+			line = '+ ' + line[len('getting '):]
+		if line.startswith('removing '):
+			line = '- ' + line[len('removing '):]
+		ui.write(line + '\n')
+	return err
+
 def hg_push(ui, repo, **opts):
 	w = uiwrap(ui)
 	ui.quiet = False
@@ -2019,7 +2038,19 @@ def sync(ui, repo, **opts):
 		raise hg_util.Abort(codereview_disabled)
 
 	if not opts["local"]:
-		err = hg_pull(ui, repo, update=True)
+		# If there are incoming CLs, pull -u will do the update.
+		# If there are no incoming CLs, do hg update to make sure
+		# that an update always happens regardless. This is less
+		# surprising than update depending on incoming CLs.
+		# It is important not to do both hg pull -u and hg update
+		# in the same command, because the hg update will end
+		# up marking resolve conflicts from the hg pull -u as resolved,
+		# causing files with <<< >>> markers to not show up in 
+		# hg resolve -l. Yay Mercurial.
+		if hg_incoming(ui, repo):
+			err = hg_pull(ui, repo, update=True)
+		else:
+			err = hg_update(ui, repo)
 		if err:
 			return err
 	sync_changes(ui, repo)