+static bool
+add_describe_ref(char *buf, int *bufpos, char *commit_id, const char *sep)
+{
+ char refbuf[SIZEOF_STR];
+ char *ref = NULL;
+ FILE *pipe;
+
+ if (!string_format(refbuf, "git describe %s", commit_id))
+ return TRUE;
+
+ pipe = popen(refbuf, "r");
+ if (!pipe)
+ return TRUE;
+
+ if ((ref = fgets(refbuf, sizeof(refbuf), pipe)))
+ ref = chomp_string(ref);
+ pclose(pipe);
+
+ if (!ref || !*ref)
+ return TRUE;
+
+ /* This is the only fatal call, since it can "corrupt" the buffer. */
+ if (!string_nformat(buf, SIZEOF_STR, bufpos, "%s%s", sep, ref))
+ return FALSE;
+
+ return TRUE;
+}
+