_ [subversion] 変更を加えて過去に行って現在に戻って破棄すると消える？

会社の人が苦しんでいた問題。

$ svn --version | head -n 2
svn, version 1.6.3 (r38063)
   compiled Jul 15 2009, 05:45:30
$ svnadmin create repository
$ svn checkout file://$PWD/repository working-copy
Checked out revision 0.
$ cd working-copy
$ echo test > file
$ svn add file
A         file
$ svn commit -m 'log'
Adding         file
Transmitting file data .
Committed revision 1.
$ svn update
At revision 1.
$ svn status -v .
                 1        1 nov          .
                 1        1 nov          file

準備完了。さて、

$ echo test >> file
$ svn status -v .
                 1        1 nov          .
M                1        1 nov          file
$ svn diff
Index: file
===================================================================
--- file	(revision 1)
+++ file	(working copy)
@@ -1 +1,2 @@
 test
+test
$ svn update -r0
   C file
At revision 0.
Summary of conflicts:
  Tree conflicts: 1
$ svn status -v .
                 0        0 nov          .
A  +  C          -        1 nov          file
      >   local edit, incoming delete upon update
$ svn update
Skipped 'file'
At revision 1.
Summary of conflicts:
  Skipped paths: 1
$ svn status -v .
                 1        1 nov          .
A  +  C          -        1 nov          file
      >   local edit, incoming delete upon update
$ svn revert file
Reverted 'file'
$ svn update
At revision 1.
$ svn status -v .
                 1        1 nov          .
?                                        file
$ svn log -v
------------------------------------------------------------------------
r1 | nov | 2009-07-27 22:48:38 +0900 (Mon, 27 Jul 2009) | 1 line
Changed paths:
   A /file

log
------------------------------------------------------------------------
$ cat file
test
test
$ rm -f file
$ svn status -v 
                 1        1 nov          .
$ svn status -v .
                 1        1 nov          .
$ svnversion 
1

file スルーされすぎだろ。

$ svn update file
A    file
Updated to revision 1.
$ cat file
test

ファイル名を指定すると戻ってくる。どの時点でどうすればこれに気づくでしょう？

とりあえず、Dealing with Structural Conflictsを読むか。