# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 1327446989 21600
# Node ID d1c74c6151c9c327b58beb93f5132bf266cdde28
# Parent  341c58282b2583e8f728714e2752fc0140eac4d2
copies: eliminate criss-crosses when chaining

Before the copies refactoring, we declared that if a and b were
present in source and destination, we ignored copies between them. The
refactored code could however report b was a copy of a and vice versa
in a situation where we looked for differences between two identical
changesets that copy a to b.

  y
 /
x
 \
  y'

diff -r 341c58282b25 -r d1c74c6151c9 mercurial/copies.py
--- a/mercurial/copies.py	Sat Jan 21 21:39:27 2012 -0600
+++ b/mercurial/copies.py	Tue Jan 24 17:16:29 2012 -0600
@@ -99,6 +99,13 @@
         if v in src:
             # file is a copy of an existing file
             t[k] = v
+
+    # remove criss-crossed copies
+    for k, v in t.items():
+        if k in src and v in dst:
+            print "bad", k, v
+            del t[k]
+
     return t
 
 def _tracefile(fctx, actx):