USE_RAND_TIEBREAKER=OFF fails to compile

[nmcglo]

The CMAKE option USE_RAND_TIEBREAKER defaults to ON. This feature was added from #185 (#184 into develop). Somewhere along the line since then, however, the option has become a requirement as the compilation will fail if USE_RAND_TIEBREAKER=OFF.

Tested compiler:

Apple clang version 21.0.0 (clang-2100.1.1.101)
Target: arm64-apple-darwin25.5.0

mpirun (Open MPI) 5.0.8

Found errors upon compilation:

[  2%] Building C object core/CMakeFiles/ROSS.dir/gvt/mpi_allreduce.c.o
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:526:5: error: call to undeclared function 'tw_copy_event_sig'; ISO C99 and later do not support
      implicit function declarations [-Wimplicit-function-declaration]
  526 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |     ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:526:46: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  526 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |                        ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:526:55: error: use of undeclared identifier 'g_tw_max_sig'
  526 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |                                                       ^~~~~~~~~~~~
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:532:2: error: call to undeclared function 'tw_copy_event_sig'; ISO C99 and later do not support
      implicit function declarations [-Wimplicit-function-declaration]
  532 |         tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |         ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:532:43: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  532 |         tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |                            ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:532:52: error: use of undeclared identifier 'g_tw_max_sig'
  532 |         tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |                                                           ^~~~~~~~~~~~
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:542:31: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  542 |     if (g_tw_gvt_hook_trigger.sig_at.tie_lineage_length >= MAX_TIE_CHAIN) {
      |         ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:545:5: error: use of undeclared identifier 'tw_event_sig'
  545 |     tw_event_sig * now = &lp->kp->last_sig; // tw_now_sig(lp);
      |     ^~~~~~~~~~~~
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:545:20: error: use of undeclared identifier 'now'
  545 |     tw_event_sig * now = &lp->kp->last_sig; // tw_now_sig(lp);
      |                    ^~~
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:545:35: error: no member named 'last_sig' in 'struct tw_kp'
  545 |     tw_event_sig * now = &lp->kp->last_sig; // tw_now_sig(lp);
      |                           ~~~~~~  ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:546:5: error: call to undeclared function 'tw_copy_event_sig'; ISO C99 and later do not support
      implicit function declarations [-Wimplicit-function-declaration]
  546 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, now);
      |     ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:546:46: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  546 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, now);
      |                        ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:546:54: error: use of undeclared identifier 'now'; did you mean 'pow'?
  546 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, now);
      |                                                      ^~~
      |                                                      pow
/Library/Developer/CommandLineTools/SDKs/MacOSX26.5.sdk/usr/include/math.h:453:15: note: 'pow' declared here
  453 | extern double pow(double, double);
      |               ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:548:27: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  548 |     g_tw_gvt_hook_trigger.sig_at.event_tiebreaker[g_tw_gvt_hook_trigger.sig_at.tie_lineage_length] = 0;
      |     ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:548:73: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  548 |     g_tw_gvt_hook_trigger.sig_at.event_tiebreaker[g_tw_gvt_hook_trigger.sig_at.tie_lineage_length] = 0;
      |                                                   ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:549:27: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  549 |     g_tw_gvt_hook_trigger.sig_at.tie_lineage_length += 1;
      |     ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:557:5: error: call to undeclared function 'tw_copy_event_sig'; ISO C99 and later do not support
      implicit function declarations [-Wimplicit-function-declaration]
  557 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |     ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:557:46: error: no member named 'sig_at' in 'struct gvt_hook_trigger'
  557 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |                        ~~~~~~~~~~~~~~~~~~~~~ ^
/Users/neil/devel/ROSS/core/gvt/mpi_allreduce.c:557:55: error: use of undeclared identifier 'g_tw_max_sig'
  557 |     tw_copy_event_sig(&g_tw_gvt_hook_trigger.sig_at, &g_tw_max_sig);
      |                                                       ^~~~~~~~~~~~
19 errors generated.
make[2]: *** [core/CMakeFiles/ROSS.dir/gvt/mpi_allreduce.c.o] Error 1
make[1]: *** [core/CMakeFiles/ROSS.dir/all] Error 2
make: *** [all] Error 2

[caitlinross]

I'm assuming since CI was broken for so long until recently that no one tested it with multiple builds. I'll be on vacation for a bit, but when I get back I'll take a stab at fixing it, and then add a job in CI that will build with USE_RAND_TIEBREAKER=OFF.

[nmcglo]

Yeah, it's been a while since I looked at the code but the errors don't seem too terrible, probably just a broken #if/#else clause. I figured I'd at least note it first before trying anything.