On an I/O error, merge_read_packet() and merge_append_read_packet() need

to return a pointer to the merge_in_file_t that got the error.  Set *err
to 0 on success and an error code on an err, treat a null return as an
EOF indication, and if we don't get a null return check for a non-zero
error code and treat that as an I/O error.

svn path=/trunk/; revision=39964

1 files changed, 7 insertions, 2 deletions

diff --git a/file.c b/file.c
index e3db476df3..f6b9af91d8 100644
--- a/file.c
+++ b/file.c
@@ -1290,8 +1290,13 @@ cf_merge_files(char **out_filenamep, int in_file_count,
       in_file = merge_read_packet(in_file_count, in_files, &read_err,
                                   &err_info);
     if (in_file == NULL) {
-      if (read_err != 0)
-        got_read_error = TRUE;
+      /* EOF */
+      break;
+    }
+
+    if (read_err != 0) {
+      /* I/O error reading from in_file */
+      got_read_error = TRUE;
       break;
     }