[PATCH 3 of 4 V5] histedit: simplify computation of edited set (issue3620)

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at logilab.fr>
# Date 1349843226 -7200
# Node ID d34351f9cb06bf64ea1dc9b9b2936fec02be8d5e
# Parent  374a63151ccb508bcf52a5ec7b2b67741e1a1853
histedit: simplify computation of edited set (issue3620)

This complex code can be replaced by two simple revset calls.

diff --git a/hgext/histedit.py b/hgext/histedit.py
--- a/hgext/histedit.py
+++ b/hgext/histedit.py
@@ -587,22 +587,10 @@
     """select and validate the set of revision to edit
 
     When keep is false, the specified set can't have children."""
-    revs = [old]
-    current = old
-    while current != new:
-        ctx = repo[current]
-        if not keep and len(ctx.children()) > 1:
-            raise util.Abort(_('cannot edit history that would orphan nodes'))
-        if len(ctx.parents()) != 1 and ctx.parents()[1] != node.nullid:
-            raise util.Abort(_("can't edit history with merges"))
-        if not ctx.children():
-            current = new
-        else:
-            current = ctx.children()[0].node()
-            revs.append(current)
-    if len(repo[current].children()) and not keep:
+    revs = list(repo.set('%n::%n', old, new))
+    if not keep and repo.revs('(%ld::) - %ld', revs, revs):
         raise util.Abort(_('cannot edit history that would orphan nodes'))
-    return revs
+    return [c.node() for c in revs]
 
 
 def writestate(repo, parentnode, rules, keep, topmost, replacements):