cmdutil: add support for evolution "troubles" display in changeset_printer

Add a "trouble" line in changeset header along with a couple of labels on
"log.changeset" line to indicate whether a changeset is troubled or not and
which kind trouble occurs.

mercurial/cmdutil.py

@@ -1144,6 +1144,10 b' def diffordiffstat(ui, repo, diffopts, n'
 
 def _changesetlabels(ctx):
     labels = ['log.changeset', 'changeset.%s' % ctx.phasestr()]
+    if ctx.troubled():
+        labels.append('changeset.troubled')
+        for trouble in ctx.troubles():
+            labels.append('trouble.%s' % trouble)
     return ' '.join(labels)
 
 class changeset_printer(object):
@@ -1252,6 +1256,10 b' class changeset_printer(object):'
         self.ui.write(_("date:        %s\n") % date,
                       label='log.date')
 
+        if ctx.troubled():
+            self.ui.write(_("trouble:     %s\n") % ', '.join(ctx.troubles()),
+                          label='ui.note log.trouble')
+
         if self.ui.debugflag:
             files = ctx.p1().status(ctx)[:3]
             for key, value in zip([# i18n: column positioning for "hg log"

tests/test-commit-amend.t

@@ -614,6 +614,7 b' Test that rewriting leaving instability '
   parent:      11:3334b7925910
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
+  trouble:     unstable
   summary:     babar