{
        struct strbuf buf = STRBUF_INIT;
        struct expand_data data;
+       int save_warning;
+       int retval = 0;
 
        if (!opt->format)
                opt->format = "%(objectname) %(objecttype) %(objectsize)";
         * warn) ends up dwarfing the actual cost of the object lookups
         * themselves. We can work around it by just turning off the warning.
         */
+       save_warning = warn_on_object_refname_ambiguity;
        warn_on_object_refname_ambiguity = 0;
 
        while (strbuf_getline(&buf, stdin, '\n') != EOF) {
-               int error;
-
                if (data.split_on_whitespace) {
                        /*
                         * Split at first whitespace, tying off the beginning
                        data.rest = p;
                }
 
-               error = batch_one_object(buf.buf, opt, &data);
-               if (error)
-                       return error;
+               retval = batch_one_object(buf.buf, opt, &data);
+               if (retval)
+                       break;
        }
 
-       return 0;
+       strbuf_release(&buf);
+       warn_on_object_refname_ambiguity = save_warning;
+       return retval;
 }
 
 static const char * const cat_file_usage[] = {