mq: fix qrefresh -e with no patches applied

hgext/mq.py

@@ -1607,6 +1607,9 b' def refresh(ui, repo, *pats, **opts):'
     q = repo.mq
     message = cmdutil.logmessage(opts)
     if opts['edit']:
+        if not q.applied:
+            ui.write(_("No patches applied\n"))
+            return 1
         if message:
             raise util.Abort(_('option "-e" incompatible with "-m" or "-l"'))
         patch = q.applied[-1].name

tests/test-mq-qrefresh-replace-log-message

@@ -8,6 +8,11 b' echo "mq=" >> $HGRCPATH'
 hg init
 hg qinit
 
+echo =======================
+echo "Should fail if no patches applied"
+hg qrefresh
+hg qrefresh -e
+
 hg qnew -m "First commit message" first-patch
 echo aaaa > file
 hg add file

tests/test-mq-qrefresh-replace-log-message.out

@@ -1,3 +1,7 b''
+=======================
+Should fail if no patches applied
+No patches applied
+No patches applied
 =======================
 Should display 'First commit message'
 description: