Annotate was being too clever trying to work in place, and triggering

Annotate was being too clever trying to work in place, and triggering
its assert. Simplify it, fix it, and speed it up a tiny bit.

--- a/mercurial/hg.py	Fri May 20 17:20:39 2005 -0800
+++ b/mercurial/hg.py	Fri May 20 17:22:02 2005 -0800
@@ -38,22 +38,18 @@
         revs.reverse()
         prev = []
         annotate = []
+        
         for node in revs:
             curr = self.read(node).splitlines(1)
             linkrev = self.linkrev(node)
             sm = SequenceMatcher(None, prev, curr)
-            offset = 0
+            new = []
             for o, m, n, s, t in sm.get_opcodes():
-                if o in ('insert','replace'):
-                    annotate[m+offset:n+offset] = \
-                        [ (linkrev, l) for l in curr[s:t]]
-                    if o == 'insert':
-                        offset += m-n
-                elif o == 'delete':
-                    del annotate[m+offset:n+offset]
-                    offset -= m-n
-            assert len(annotate) == len(curr)
-            prev = curr
+                if o == 'equal':
+                    new += annotate[m:n]
+                else:
+                    new += [(linkrev, l) for l in curr[s:t]]
+            annotate, prev = new, curr
         return annotate
 
 class manifest(revlog):