Fix bug #345.

The last hit for a file might have been before the last window, so we
can't clear copies. To reduce the load, we only store real copy
entries instead of storing hashes for every revision.

mercurial/commands.py

@@ -1526,7 +1526,6 b' def grep(ui, repo, pattern, *pats, **opt'
         if st == 'window':
             incrementing = rev
             matches.clear()
-            copies.clear()
         elif st == 'add':
             change = repo.changelog.read(repo.lookup(str(rev)))
             mf = repo.manifest.read(change[0])
@@ -1535,20 +1534,19 b' def grep(ui, repo, pattern, *pats, **opt'
                 if fn in skip:
                     continue
                 fstate.setdefault(fn, {})
-                copies.setdefault(rev, {})
                 try:
                     grepbody(fn, rev, getfile(fn).read(mf[fn]))
                     if follow:
                         copied = getfile(fn).renamed(mf[fn])
                         if copied:
-                            copies[rev][fn] = copied[0]
+                            copies.setdefault(rev, {})[fn] = copied[0]
                 except KeyError:
                     pass
         elif st == 'iter':
             states = matches[rev].items()
             states.sort()
             for fn, m in states:
-                copy = copies[rev].get(fn)
+                copy = copies.get(rev, {}).get(fn)
                 if fn in skip:
                     if copy:
                         skip[copy] = True
@@ -1571,7 +1569,7 b' def grep(ui, repo, pattern, *pats, **opt'
         for fn, state in fstate:
             if fn in skip:
                 continue
-            if fn not in copies[prev[fn]]:
+            if fn not in copies.get(prev[fn], {}):
                 display(fn, rev, {}, state)
     return (count == 0 and 1) or 0