Non-zero return code when copying a file from another user which is already present

When I do something like dsync file destfile; echo $?; dsync file destfile; echo $? - both the echos show 0. But, if I do dsync ~another_user/file destfile; echo $?; dsync ~another_user/file destfile; echo$? - the first echo will be 0, and the second will be 1. This build is compiled with xattrs, lustre, etc. But, it does not appear to be lustre related. If I do -X none, it still returns 1.

I've tried a build with XATTRS off, but the same non-zero return code is provided.

The output from dsync is identical when copied from another user or my own space.

[2026-02-04T03:31:15] Walked 1 items in 0.001 secs (859.593 items/sec) ...
[2026-02-04T03:31:15] Walked 1 items in 0.001 seconds (835.713 items/sec)
[2026-02-04T03:31:15] Comparing file sizes and modification times of 1 items
[2026-02-04T03:31:15] Started   : Feb-04-2026, 03:31:15
[2026-02-04T03:31:15] Completed : Feb-04-2026, 03:31:15
[2026-02-04T03:31:15] Seconds   : 0.000
[2026-02-04T03:31:15] Items     : 1
[2026-02-04T03:31:15] Item Rate : 1 items in 0.000154 seconds (6507.841738 items/sec)
[2026-02-04T03:31:15] Updating timestamps on newly copied files
[2026-02-04T03:31:15] Completed updating timestamps
[2026-02-04T03:31:15] Completed sync

Given this was a success, it should be returning a 0 status.

A quick look, and it appears to be the int tmp_rc = dsync_strmap_compare area. That is returning a tmp_rc < 0 (actual value of -1). Specifically, it is this function

              /* copy metadata values from source to destination, if needed */
              tmp_rc = mfu_flist_file_sync_meta(src_list, src_index, dst_list,
                                                dst_index, mfu_dst_file);

Looking at that function, my guess would be

     /* get owner and group ids */
      uid_t src_uid = (uid_t) mfu_flist_file_get_uid(src_list, src_index);
      gid_t src_gid = (gid_t) mfu_flist_file_get_gid(src_list, src_index);

      uid_t dst_uid = (uid_t) mfu_flist_file_get_uid(dst_list, dst_index);
      gid_t dst_gid = (gid_t) mfu_flist_file_get_gid(dst_list, dst_index);

      /* update ownership on destination if needed */
      if ((src_uid != dst_uid) || (src_gid != dst_gid)) {
          tmp_rc = mfu_copy_ownership(src_list, src_index, dest_path, mfu_file);
          if (tmp_rc < 0) {
              rc = -1;
          }
      }

This is trying to force ownership to be identical. I do not understand why as people surely would want to copy data from other users? I can't see a way to disable this either.

Reproduce the two dsync commands with a file from another user and compare the return codes. Start at dsync_strmap_compare and mfu_flist_file_sync_meta, especially the mfu_copy_ownership call, to trace why an already-successful sync returns -1. Add or update coverage for this case so a completed sync reports status 0, while preserving the intended metadata behavior.