mbox: Added assert to try to catch corruption.

diff --git a/src/lib-storage/index/mbox/mbox-sync.c b/src/lib-storage/index/mbox/mbox-sync.c
index 744098c14817b2b708b20e426ae72e83456631ce..b938e912b410735e0295474c96e8cba833110a59 100644 (file)
--- a/src/lib-storage/index/mbox/mbox-sync.c
+++ b/src/lib-storage/index/mbox/mbox-sync.c
@@ -651,6 +651,8 @@ static int mbox_sync_handle_header(struct mbox_sync_mail_context *mail_ctx)
                /* read the From-line before rewriting overwrites it */
                if (mbox_read_from_line(mail_ctx) < 0)
                        return -1;
+               i_assert(mail_ctx->mail.from_offset + move_diff != 1 &&
+                        mail_ctx->mail.from_offset + move_diff != 2);
 
                mbox_sync_update_header(mail_ctx);
                ret = mbox_sync_try_rewrite(mail_ctx, move_diff);