largefiles: drop orphan entries from lfdristat at "hg rollback"

Before this patch, newly added (but not yet committed) largefiles
aren't treated as unknown ("?") after "hg rollback".

After "hg rollback", lfdirstate still contains "A" status entries for
such largefiles, even though corresponding entries for standins are
already dropped from dirstate.

Such "orphan" entries in lfdirstate prevent unknown (large)files in
the working directory from being listed up in "unknown" list. The code
path in "if working" route of "lfilesrepo.status" below drops
largefiles tracked in lfdirstate from "unknown" list:

    lfiles = set(lfdirstate._map)
    # Unknown files
    result[4] = set(result[4]).difference(lfiles)

This patch drops orphan entries from lfdristate at "hg rollback".

This is a temporary way to fix with less changes. For fundamental
resolution of this kind of problems in the future, lfdirstate should
be rollback-ed as a part of transaction, as same as dirstate.

hgext/largefiles/overrides.py

@@ -1147,9 +1147,13 b' def overriderollback(orig, ui, repo, **o'
                      partial=lfutil.isstandin)
 
         lfdirstate = lfutil.openlfdirstate(ui, repo)
+        orphans = set(lfdirstate)
         lfiles = lfutil.listlfiles(repo)
         for file in lfiles:
             lfutil.synclfdirstate(repo, lfdirstate, file, True)
+            orphans.discard(file)
+        for lfile in orphans:
+            lfdirstate.drop(lfile)
         lfdirstate.write()
     finally:
         wlock.release()

tests/test-largefiles-update.t

@@ -107,12 +107,16 b' Test that "hg rollback" restores status '
   $ echo largeX > largeX
   $ hg add --large largeX
   $ hg commit -m 'will be rollback-ed soon'
+  $ echo largeY > largeY
+  $ hg add --large largeY
   $ hg status -A large1
   large1: No such file or directory
   $ hg status -A large2
   ? large2
   $ hg status -A largeX
   C largeX
+  $ hg status -A largeY
+  A largeY
   $ hg rollback
   repository tip rolled back to revision 3 (undo commit)
   working directory now based on revision 3
@@ -122,5 +126,7 b' Test that "hg rollback" restores status '
   R large2
   $ hg status -A largeX
   A largeX
+  $ hg status -A largeY
+  ? largeY
 
   $ cd ..