fixup! job-manager: update running jobs if necessary after R update

src/modules/job-manager/update.c

@@ -71,8 +71,6 @@
 #if HAVE_CONFIG_H
 #include "config.h"
 #endif
-#include <math.h>
-
 #include <flux/core.h>
 
 #include "src/common/libutil/errprintf.h"
@@ -653,29 +651,36 @@ static void resource_update_cb (flux_future_t *f, void *arg)
     }
     job = zlistx_first (jobs);
     while (job) {
-        double expiration;
         if (job->state & FLUX_JOB_STATE_RUNNING && job->R_redacted) {
+            double expiration = 0.;
+            double duration = 0.;
+            /*
+             *  Get current job expiration and jobspec duration.
+             *  Assume the expiration job of the job needs to be updated
+             *  only if and expiration was set for the job _and_ the job
+             *  duration was unset or 0. This indicates that the expiration
+             *  was likely automatically set by the scheduler based on
+             *  the instance expiration (which is now being updated).
+             *
+             */
             if (json_unpack (job->R_redacted,
                             "{s:{s:F}}",
                             "execution",
-                             "expiration", &expiration) < 0) {
+                             "expiration", &expiration) < 0
+                || json_unpack (job->jobspec_redacted,
+                                "{s:{s:{s?F}}",
+                                "attributes",
+                                 "system",
+                                  "duration", &duration) < 0) {
                 flux_log (h,
                           LOG_ERR,
-                          "%s: failed to unpack current expiration for update",
+                          "failed to unpack job %s data for expiration update",
                           idf58 (job->id));
             }
-
-            /*
-             *  Only update the expiration of jobs where the old expiration
-             *  exactly matches the previous resource set expiration. It
-             *  should be safe to directly compare the two double precision
-             *  expiration values, since the scheduler should have set the
-             *  expiration of jobs to the exact value of the previous value,
-             *  however, some schedulers may work in time_t or other integral
-             *  values for starttime and expiration (e.g. Fluxion), so check
-             *  for a difference of up to 1s just in case.
+            /*  Job needs an update if no or unlimited duration specified
+             *  (duration == 0.) but an expiration was set (expiration > 0.):
              */
-            if (fabs (expiration - old_expiration) < 1.) {
+            if (expiration > 0. && duration == 0.) {
                 flux_log (h,
                           LOG_DEBUG,
                           "adjusting expiration of %s from %.2f to %.2f",