Re: Feature request, mv

[Jim Meyering]

address@hidden (Eric Blake) wrote:
>> Once it knows the target (b) is a directory, if you're using -T, mv knows
>> that it must fail -- rename ("anything", "directory") will always fail.
>
> Only if "directory" is not empty.

or if the "old argument" is a non-directory.

> POSIX requires "If the old argument
> points to the pathname of a directory, the new argument shall not
> point to the pathname of a file that is not a directory. If the directory
> named by the new argument exists, it shall be removed and old
> renamed to new. In this case, a link named new shall exist throughout
> the renaming operation and shall refer either to the directory referred
> to by new or old before the operation began. If new names an existing
> directory, it shall be required to be an empty directory."
>
> Therefore, we have found another 'mv -f -T' bug:
>
> $ mkdir dir other
> $ mv -fT other dir
>
> should succeed, not fail.

Yes.  Thanks.

Before

  $ rm -rf e d; mkdir d e; ./mv -T d e
  ./mv: cannot overwrite directory `e'

After:

  $ rm -rf e d; mkdir d e; ./mv -T d e
  $

Here's the patch:

2006-05-11  Jim Meyering  <address@hidden>

        * Version 6.0-cvs.

        mv -T DIR EMPTY_DIR no longer fails unconditionally
        * src/copy.c (copy_internal): Don't manually prohibit a move where
        the destination is an existing directory.  Sometimes doing that is
        valid.  Let the rename system call enforce the rules.  That is
        allowed only when the source is a directory and the destination
        directory (to be replaced) is empty.  Reported by Eric Blake.
        * tests/mv/no-target-dir: New file/test for this.
        * tests/mv/Makefile.am (TESTS): Add no-target-dir.
        * NEWS: Mention this.

Index: src/copy.c
===================================================================
RCS file: /fetish/cu/src/copy.c,v
retrieving revision 1.198
retrieving revision 1.199
diff -u -p -u -r1.198 -r1.199
--- src/copy.c  11 May 2006 07:33:00 -0000      1.198
+++ src/copy.c  11 May 2006 08:55:04 -0000      1.199
@@ -1157,14 +1157,6 @@ copy_internal (char const *src_name, cha
 
          if (x->move_mode)
            {
-             /* In move_mode, DEST may not be an existing directory.  */
-             if (S_ISDIR (dst_sb.st_mode) && x->backup_type == no_backups)
-               {
-                 error (0, 0, _("cannot overwrite directory %s"),
-                        quote (dst_name));
-                 return false;
-               }
-
              /* Don't allow user to move a directory onto a non-directory.  */
              if (S_ISDIR (src_sb.st_mode) && !S_ISDIR (dst_sb.st_mode)
                  && x->backup_type == no_backups)