[Gnu-arch-users] revert accidentally committed merge

[Robert Widhopf-Fenk]

Hi,

accidental chances of a commit can easily be reverted by
reversely replaying the patches and then doing a sync-tree
(as described in the wiki [1]).

However, this does not work as intended when the accidental
change comes from a merge, since sync-tree will also keep
the patch-logs coming from the merge.  In fact I only want
those patch-logs of the tree.  While I could archive this by
deleting the offending patch-logs by hand it is not really
user-friendly.

Why are those patch-logs bad?  Because they will prevent me
from merging those patches they come from.  I had been
merging from a 1.1 version to my 0.9 while the 1.1 had already
some patches from another 0.9 tree.  Then when merging to my
0.9 from the right 0.9 tree I got conflicts due to some
patches which were not merged as their patch-logs were
already present in my 0.9 tree due to the sync-tree.

For this case it would be nice to limit sync-tree to the
patch-logs of the current tree. (= feature request)

So is there another easy way to revert from an accidentally 
committed merge? 

If there are no other commits in between I could tag from
the last good revision, but Toms tutorial [2] says that one
should not do this as it may break/affect merging when
having trees with mixed tag/commit patches.

What would be those bad effects when I tag into a commit
based branch?

Cheers Robert

[1] 
http://wiki.gnuarch.org/Tla_20Reference_2fsync_2dtree?action=highlight&value=sync-tree
[2] 
http://regexps.srparish.net/www/tutorial/html/symbolic-tags.html#Symbolic_Tags