copies: correctly skip directories that have already been considered

Previously, `if dsrc in invalid` would never be true, since we added
`dsrc +"/"` to invalid, not `dsrc` itself. Since it's much more common for
individual files (not whole directories) to be moved, it seemed cleaner to
delay appending the "/" until we know we have some directory moves to
actually consider.

I haven't benchmarked this, but I imagine this is a mild performance win.

Differential Revision: https://phab.mercurial-scm.org/D4284

mercurial/copies.py

@@ -593,16 +593,16 b' def _fullcopytracing(repo, c1, c2, base)'
             continue
         elif dsrc in d1 and ddst in d1:
             # directory wasn't entirely moved locally
-            invalid.add(dsrc + "/")
+            invalid.add(dsrc)
         elif dsrc in d2 and ddst in d2:
             # directory wasn't entirely moved remotely
-            invalid.add(dsrc + "/")
-        elif dsrc + "/" in dirmove and dirmove[dsrc + "/"] != ddst + "/":
+            invalid.add(dsrc)
+        elif dsrc in dirmove and dirmove[dsrc] != ddst:
             # files from the same directory moved to two different places
-            invalid.add(dsrc + "/")
+            invalid.add(dsrc)
         else:
             # looks good so far
-            dirmove[dsrc + "/"] = ddst + "/"
+            dirmove[dsrc] = ddst
 
     for i in invalid:
         if i in dirmove:
@@ -612,6 +612,8 b' def _fullcopytracing(repo, c1, c2, base)'
     if not dirmove:
         return copy, {}, diverge, renamedelete, {}
 
+    dirmove = {k + "/": v + "/" for k, v in dirmove.iteritems()}
+
     for d in dirmove:
         repo.ui.debug("   discovered dir src: '%s' -> dst: '%s'\n" %
                       (d, dirmove[d]))