3e922f07e4d8c51a3b989e3dc6748e33f8516e3b
braney
  Mon Jun 22 09:10:05 2026 -0700
Document two -O3 cleanup details raised in v500 code review

Follow-up to code review #37767, addressing two points on commit f57fc11d951:

- The else guards in sanger22gtf.c and bottleneck.c looked like leftovers from
before errAbort was marked noreturn, but they are still required: removing
either one reintroduces -Werror=format-overflow at -O3, because that warning
runs before the noreturn-based dead-path pruning.  Added a comment at each
else saying so.

- makeGrayShades (hgGene/altSplice.c and hgTracks/simpleTracks.c) writes
shadesOfGray[maxShade+1] = MG_RED as an overflow sentinel.  Spelled this out
in both function descriptions so the maxShade+2 array sizing is documented at
the function, not just at the caller.

Comment-only; no behavior change.

refs #37767 refs #37761

diff --git src/weblet/bottleneck/bottleneck.c src/weblet/bottleneck/bottleneck.c
index b1b89cdbce3..102269e352c 100644
--- src/weblet/bottleneck/bottleneck.c
+++ src/weblet/bottleneck/bottleneck.c
@@ -221,31 +221,31 @@
 void queryServer(char *ip, int count, double fraction)
 /* Query bottleneck server - just for testing.
  * Main query is over ip port. */
 {
 int i;
 char sendString[256];
 safef(sendString, sizeof(sendString), "%s %f", ip, fraction);
 for (i=0; i<count; ++i)
     {
     int socket = netMustConnect(host, port);
     char buf[256], *s;
     netSendString(socket, sendString);
     s = netGetString(socket, buf);
     if (s == NULL)
         errAbort("Shut out by bottleneck server %s:%d", host, port);
-    else
+    else // guard printf: -Wformat-overflow runs before errAbort's noreturn prunes the null path
         printf("%s millisecond delay recommended\n", s);
     close(socket);
     }
 }
 
 void setUser(char *ip, char *millis)
 /* Set user current delay. */
 {
 int socket = netMustConnect(host, port);
 char buf[256];
 safef(buf, sizeof(buf), "?set %s %s", ip, millis);
 netSendString(socket, buf);
 close(socket);
 }