rebase: abort hg pull --rebase if rebase.requiredest is set (issue5514)

Previously, the pull would succeed, but the subsequent rebase would fail due
to the rebase.requiredest flag. Now abort earlier with a more useful error
message.

hgext/rebase.py

@@ -1362,6 +1362,11 def pullrebase(orig, ui, repo, *args, **
     'Call rebase after pull if the latter has been invoked with --rebase'
     ret = None
     if opts.get('rebase'):
+        if ui.configbool('commands', 'rebase.requiredest'):
+            msg = _('rebase destination required by configuration')
+            hint = _('use hg pull followed by hg rebase -d DEST')
+            raise error.Abort(msg, hint=hint)
+
         wlock = lock = None
         try:
             wlock = repo.wlock()

tests/test-rebase-dest.t

@@ -72,13 +72,7 Check rebase.requiredest interaction wit
   $ echo f > f
   $ hg commit -qAm ff
   $ hg pull --rebase
-  pulling from $TESTTMP/repo
-  searching for changes
-  adding changesets
-  adding manifests
-  adding file changes
-  added 1 changesets with 2 changes to 2 files (+1 heads)
-  abort: you must specify a destination
-  (use: hg rebase -d REV)
+  abort: rebase destination required by configuration
+  (use hg pull followed by hg rebase -d DEST)
   [255]