diff --git a/hgext3rd/undo.py b/hgext3rd/undo.py
--- a/hgext3rd/undo.py
+++ b/hgext3rd/undo.py
@@ -75,7 +75,13 @@
     else:
         rootlog = False
 
-    result = orig(lui, repo, cmd, fullargs, *args)
+    unfinished = False
+    try:
+        result = orig(lui, repo, cmd, fullargs, *args)
+    except error.InterventionRequired as inst:
+        # handle commands that pause: eg histedit with merge conflict
+        unfinished = True
+        command = command + ['\0']
 
     # mercurial is bad with caches
     # eg update to hidden commit will leave false cache
@@ -86,6 +92,9 @@
     if rootlog:
         safelog(repo, command)
         del os.environ['_undologactive']
+
+    if unfinished:
+        raise error.InterventionRequired(inst)
     return result
 
 # Write: Log control
@@ -589,9 +598,13 @@
     if branch and reverseindex != 1 and reverseindex != -1:
         raise error.Abort(_("--branch with --index not supported"))
     if relativeundo:
-        reverseindex = _computerelative(repo, reverseindex,
-                                        absolute = not relativeundo,
-                                        branch = branch)
+        try:
+            reverseindex = _computerelative(repo, reverseindex,
+                                            absolute = not relativeundo,
+                                            branch = branch)
+        except IndexError:
+            raise error.Abort(_("index out of bounds"))
+
     if branch and preview:
         raise error.Abort(_("--branch with --preview not supported"))
 
@@ -674,7 +687,10 @@
         commandstr = _readnode(repo, 'command.i', nodedict['command'])
         commandlist = commandstr.split("\0")
 
-        if commandlist[0] == "undo":
+        if "" in commandlist:
+            # don't want to redo to an interupted state
+            reverseindex += 1
+        elif commandlist[0] == "undo":
             undoopts = {}
             # remove both cases of "undo": it appears as an element of fullargs
             # and as the cmd.  See runcommand wrapper
@@ -807,6 +823,10 @@
     # redonode storage
     # allows for branch undos using
     # findnextdelta logic
+    if reverseindex != 0:
+        sign = reverseindex / abs(reverseindex)
+    else:
+        sign = None
     if not absolute:
         try: # attempt to get relative shift
             nodebranch = repo.vfs.read("undolog/redonode").split("\0")
@@ -849,6 +869,17 @@
             shiftedindex = _findnextdelta(repo, shiftedindex, branch,
                                           direction=sign)
         reverseindex = shiftedindex
+    # skip interupted commands
+    if sign:
+        done = False
+        rlog = _getrevlog(repo, 'index.i')
+        while not done:
+            indexdict = _readindex(repo, reverseindex, rlog)
+            commandstr = _readnode(repo, "command.i", indexdict["command"])
+            if commandstr and "\0" == commandstr[-1]:
+                reverseindex += sign
+            else:
+                done = True
     return reverseindex
 
 def _findnextdelta(repo, reverseindex, branch, direction):
@@ -888,6 +919,10 @@
             nodedict = _readindex(repo, incrementalindex)
         except IndexError:
             raise error.Abort(_("index out of bounds"))
+        # skip interupted commands
+        commandstr = _readnode(repo, "command.i", nodedict["command"])
+        if commandstr and "\0" == commandstr[-1]:
+            break
         # check wkp, commits, bookmarks
         workingcopyparent = _readnode(repo, "workingparent.i",
                                       nodedict["workingparent"])
diff --git a/tests/test-undo.t b/tests/test-undo.t
--- a/tests/test-undo.t
+++ b/tests/test-undo.t
@@ -1087,3 +1087,165 @@
   o  23   a0b72b3048d6   1970-01-01 00:00 +0000   test
   |    prev1
   ~
+
+Interupted commands
+Commands like hg rebase, unshelve and histedit may interupt in order for the
+user to solve merge conflicts etc.  Since for example hg rebase --abort may
+permanently delete a commit, we do not want to undo to this state.
+  $ touch afile
+  $ echo "afile" > afile
+  $ hg add afile && hg ci -m afile
+  $ hg up 0963b9e31e70
+  3 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ touch afile
+  $ echo "bfile" > afile
+  $ hg add afile && hg ci -m bfile
+  $ hg log -G -T compact -l6
+  @  31[tip]:29   00617a57f780   1970-01-01 00:00 +0000   test
+  |    bfile
+  |
+  | o  30:24   28dfc398cab7   1970-01-01 00:00 +0000   test
+  | |    afile
+  | |
+  o |  29   0963b9e31e70   1970-01-01 00:00 +0000   test
+  | |    c3
+  | |
+  o |  28   4e0ac6fa4ca0   1970-01-01 00:00 +0000   test
+  | |    c2
+  | |
+  o |  27:-1   c54b1b73bb58   1970-01-01 00:00 +0000   test
+   /     c1
+  |
+  o  24:-1   90af9088326b   1970-01-01 00:00 +0000   test
+       b1
+  
+  $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > rebase =
+  > EOF
+  $ hg rebase -r 00617 -d 28dfc
+  rebasing 31:00617a57f780 "bfile" (tip)
+  merging afile
+  warning: conflicts while merging afile! (edit, then use 'hg resolve --mark')
+  unresolved conflicts (see hg resolve, then hg rebase --continue)
+  [1]
+  $ hg log -G -T compact -l6
+  @  31[tip]:29   00617a57f780   1970-01-01 00:00 +0000   test
+  |    bfile
+  |
+  | @  30:24   28dfc398cab7   1970-01-01 00:00 +0000   test
+  | |    afile
+  | |
+  o |  29   0963b9e31e70   1970-01-01 00:00 +0000   test
+  | |    c3
+  | |
+  o |  28   4e0ac6fa4ca0   1970-01-01 00:00 +0000   test
+  | |    c2
+  | |
+  o |  27:-1   c54b1b73bb58   1970-01-01 00:00 +0000   test
+   /     c1
+  |
+  o  24:-1   90af9088326b   1970-01-01 00:00 +0000   test
+       b1
+  
+  $ hg resolve -m afile
+  (no more unresolved files)
+  continue: hg rebase --continue
+  $ hg rebase --continue
+  rebasing 31:00617a57f780 "bfile" (tip)
+  $ hg log -G -T compact -l6
+  @  32[tip]:30   e642892c5cb0   1970-01-01 00:00 +0000   test
+  |    bfile
+  |
+  o  30:24   28dfc398cab7   1970-01-01 00:00 +0000   test
+  |    afile
+  |
+  | o  29   0963b9e31e70   1970-01-01 00:00 +0000   test
+  | |    c3
+  | |
+  | o  28   4e0ac6fa4ca0   1970-01-01 00:00 +0000   test
+  | |    c2
+  | |
+  | o  27:-1   c54b1b73bb58   1970-01-01 00:00 +0000   test
+  |      c1
+  |
+  o  24:-1   90af9088326b   1970-01-01 00:00 +0000   test
+       b1
+  
+  $ hg undo
+  4 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg log -G -T compact -l6
+  @  31[tip]:29   00617a57f780   1970-01-01 00:00 +0000   test
+  |    bfile
+  |
+  | o  30:24   28dfc398cab7   1970-01-01 00:00 +0000   test
+  | |    afile
+  | |
+  o |  29   0963b9e31e70   1970-01-01 00:00 +0000   test
+  | |    c3
+  | |
+  o |  28   4e0ac6fa4ca0   1970-01-01 00:00 +0000   test
+  | |    c2
+  | |
+  o |  27:-1   c54b1b73bb58   1970-01-01 00:00 +0000   test
+   /     c1
+  |
+  o  24:-1   90af9088326b   1970-01-01 00:00 +0000   test
+       b1
+  
+  $ hg redo
+  2 files updated, 0 files merged, 3 files removed, 0 files unresolved
+  $ hg log -G -T compact -l6
+  @  32[tip]:30   e642892c5cb0   1970-01-01 00:00 +0000   test
+  |    bfile
+  |
+  o  30:24   28dfc398cab7   1970-01-01 00:00 +0000   test
+  |    afile
+  |
+  | o  29   0963b9e31e70   1970-01-01 00:00 +0000   test
+  | |    c3
+  | |
+  | o  28   4e0ac6fa4ca0   1970-01-01 00:00 +0000   test
+  | |    c2
+  | |
+  | o  27:-1   c54b1b73bb58   1970-01-01 00:00 +0000   test
+  |      c1
+  |
+  o  24:-1   90af9088326b   1970-01-01 00:00 +0000   test
+       b1
+  
+  $ hg undo
+  4 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg rebase -r 00617 -d 28dfc
+  rebasing 31:00617a57f780 "bfile" (tip)
+  merging afile
+  warning: conflicts while merging afile! (edit, then use 'hg resolve --mark')
+  unresolved conflicts (see hg resolve, then hg rebase --continue)
+  [1]
+  $ hg rebase --abort
+  rebase aborted
+  $ hg undo
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg log -G -T compact -l6
+  @  31[tip]:29   00617a57f780   1970-01-01 00:00 +0000   test
+  |    bfile
+  |
+  | o  30:24   28dfc398cab7   1970-01-01 00:00 +0000   test
+  | |    afile
+  | |
+  o |  29   0963b9e31e70   1970-01-01 00:00 +0000   test
+  | |    c3
+  | |
+  o |  28   4e0ac6fa4ca0   1970-01-01 00:00 +0000   test
+  | |    c2
+  | |
+  o |  27:-1   c54b1b73bb58   1970-01-01 00:00 +0000   test
+   /     c1
+  |
+  o  24:-1   90af9088326b   1970-01-01 00:00 +0000   test
+       b1
+  
+  $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > rebase =!
+  > EOF