job-list: store copy of jobspec internally

Problem: In the near future we will need access to the job's
jobspec when a job goes inactive, but we do not store a copy
of it.

Solution: Store a reference to the jobspec in struct job.  As a
side effect, we no longer need to store several jobspec sub-objects
within struct job.

Author: chu11

src/modules/job-list/job_state.c

@@ -122,8 +122,7 @@ static void job_destroy (void *data)
         free (job->nodelist);
         json_decref (job->annotations);
         grudgeset_destroy (job->dependencies);
-        json_decref (job->jobspec_job);
-        json_decref (job->jobspec_cmd);
+        json_decref (job->jobspec);
         json_decref (job->R);
         json_decref (job->exception_context);
         zlist_destroy (&job->next_states);
@@ -397,7 +396,9 @@ static int jobspec_parse (struct list_ctx *ctx,
 {
     json_error_t error;
     json_t *jobspec = NULL;
-    json_t *tasks, *resources, *command, *jobspec_job = NULL;
+    json_t *jobspec_job = NULL;
+    json_t *command = NULL;
+    json_t *tasks, *resources;
     int rc = -1;
 
     if (!(jobspec = json_loads (s, 0, &error))) {
@@ -407,6 +408,8 @@ static int jobspec_parse (struct list_ctx *ctx,
         goto error;
     }
 
+    job->jobspec = json_incref (jobspec);
+
     if (json_unpack_ex (jobspec, &error, 0,
                         "{s:{s:{s?:o}}}",
                         "attributes",
@@ -426,7 +429,6 @@ static int jobspec_parse (struct list_ctx *ctx,
                       __FUNCTION__, (uintmax_t)job->id);
             goto nonfatal_error;
         }
-        job->jobspec_job = json_incref (jobspec_job);
     }
 
     if (json_unpack_ex (jobspec, &error, 0,
@@ -453,10 +455,8 @@ static int jobspec_parse (struct list_ctx *ctx,
         goto nonfatal_error;
     }
 
-    job->jobspec_cmd = json_incref (command);
-
-    if (job->jobspec_job) {
-        if (json_unpack_ex (job->jobspec_job, &error, 0,
+    if (jobspec_job) {
+        if (json_unpack_ex (jobspec_job, &error, 0,
                             "{s?:s}",
                             "name", &job->name) < 0) {
             flux_log (ctx->h, LOG_ERR,
@@ -469,7 +469,7 @@ static int jobspec_parse (struct list_ctx *ctx,
     /* If user did not specify job.name, we treat arg 0 of the command
      * as the job name */
     if (!job->name) {
-        json_t *arg0 = json_array_get (job->jobspec_cmd, 0);
+        json_t *arg0 = json_array_get (command, 0);
         if (!arg0 || !json_is_string (arg0)) {
             flux_log (ctx->h, LOG_ERR,
                       "%s: job %ju invalid job command",

src/modules/job-list/job_state.h

@@ -101,8 +101,7 @@ struct job {
     struct grudgeset *dependencies;
 
     /* cache of job information */
-    json_t *jobspec_job;
-    json_t *jobspec_cmd;
+    json_t *jobspec;
     json_t *R;
     json_t *exception_context;