diff -r cc09cfea3dd4 -r 47d0843647d1 mercurial/util.py
--- a/mercurial/util.py	Tue Jan 07 22:29:57 2014 +0100
+++ b/mercurial/util.py	Sun Jan 12 23:28:21 2014 +0100
@@ -1983,3 +1983,20 @@
         self._hooks.sort(key=lambda x: x[0])
         for source, hook in self._hooks:
             hook(*args)
+
+def debugstacktrace(msg='stacktrace', skip=0, f=sys.stderr):
+    '''Writes a message to f (stderr) with a nicely formatted stacktrace.
+    Skips the 'skip' last entries.
+    It can be used everywhere and do intentionally not require an ui object.
+    Not be used in production code but very convenient while developing.
+    '''
+    f.write('%s at:\n' % msg)
+    entries = [('%s:%s' % (fn, ln), func)
+        for fn, ln, func, _text in traceback.extract_stack()[:-skip - 1]]
+    if entries:
+        fnmax = max(len(entry[0]) for entry in entries)
+        for fnln, func in entries:
+            f.write(' %-*s in %s\n' % (fnmax, fnln, func))
+
+# convenient shortcut
+dst = debugstacktrace