Parse jobspec attributes.system optionally

Problem: Per RFC14, the "system" key under "attributes"
is not required.  However, while parsing the jobspec a number
of unpacking code instances did something similar to the following:

json_unpack ("{s:{s:{s?s}}}", "attributes", "system", "foo", &s);

The code is attempting to unpack the optional field
"attributes.system.foo", but is saying "attributes" and "attributes.system"
are required.  This has the potential to lead to unintentional
parsing errors.

Note that for JobspecV1 in RFC25, the "system" field is required
under attributes due to the requirement for the "duration" field.
This is likely why code was written this way.

Solution: Update all code like the above into a style like:

json_unpack ("{s:{s?{s?s}}}", "attributes", "system", "foo", &s);

Where the "system" key is optional.

Note that we do NOT update unpacking instances like this:

json_unpack ("{s:{s:{s:s}}}", "attributes", "system", "foo", &s);

In instances like this, "attributes.system.foo" is required for that
particular circumstance.  Therefore "attributes.system" is also
required.

Author: chu11

src/modules/job-exec/sdexec.c

@@ -262,7 +262,7 @@ static struct sdexec *sdexec_create (flux_t *h,
     se->stderrlog = SDEXEC_LOG_EVENTLOG;
 
     (void) json_unpack_ex (job->jobspec, NULL, 0,
-                           "{s:{s:{s:{s:{s?b s?s s?s s?b}}}}}",
+                           "{s:{s?{s?{s?{s?b s?s s?s s?b}}}}}",
                            "attributes", "system", "exec", "sd",
                            "test_exec_fail", &se->test_exec_fail,
                            "stdoutlog", &stdoutlog,

src/modules/job-list/job_data.c

@@ -175,7 +175,7 @@ static int parse_per_resource (struct job *job,
     json_t *o = NULL;
 
     if (json_unpack_ex (job->jobspec, &error, 0,
-                        "{s:{s:{s?:{s?:{s?:o}}}}}",
+                        "{s:{s?{s?:{s?:{s?:o}}}}}",
                         "attributes",
                           "system",
                             "shell",
@@ -276,7 +276,7 @@ static int parse_jobspec (struct job *job, const char *s, bool allow_nonfatal)
     }
 
     if (json_unpack_ex (job->jobspec, &error, 0,
-                        "{s:{s:{s?:o}}}",
+                        "{s:{s?{s?:o}}}",
                         "attributes",
                         "system",
                         "job",
@@ -309,7 +309,7 @@ static int parse_jobspec (struct job *job, const char *s, bool allow_nonfatal)
         goto nonfatal_error;
 
     if (json_unpack_ex (job->jobspec, &error, 0,
-                        "{s:{s:{s?:s s?s}}}",
+                        "{s:{s?{s?:s s?s}}}",
                         "attributes",
                         "system",
                         "cwd", &job->cwd,

src/modules/job-manager/job.c

@@ -161,7 +161,7 @@ static int jobspec_redacted_parse_queue (struct job *job)
          * optional
          */
         if (json_unpack (job->jobspec_redacted,
-                         "{s?{s?{s?s}}}",
+                         "{s:{s?{s?s}}}",
                          "attributes",
                          "system",
                          "queue", &job->queue) < 0) {

src/modules/job-manager/plugins/alloc-bypass.c

@@ -182,7 +182,7 @@ static int validate_cb (flux_plugin_t *p,
 
     if (flux_plugin_arg_unpack (args,
                                 FLUX_PLUGIN_ARG_IN,
-                                "{s:i s:{s:{s:{s?{s?o}}}}}",
+                                "{s:i s:{s:{s?{s?{s?o}}}}}",
                                 "userid", &userid,
                                 "jobspec",
                                  "attributes",

src/modules/job-manager/plugins/limit-job-size.c

@@ -393,7 +393,7 @@ static int validate_cb (flux_plugin_t *p,
     if (json_unpack_ex (jobspec,
                         &jerror,
                         0,
-                        "{s?{s?{s?s}}}",
+                        "{s:{s?{s?s}}}",
                         "attributes",
                           "system",
                             "queue", &queue) < 0) {

src/modules/sched-simple/sched.c

@@ -127,7 +127,7 @@ jobreq_create (const flux_msg_t *msg)
         job->errnum = errno;
     }
     if (json_unpack (jobspec,
-                     "{s?{s?{s?O}}}",
+                     "{s:{s?{s?O}}}",
                      "attributes",
                      "system",
                      "constraints", &job->constraints) < 0) {
@@ -618,7 +618,7 @@ static void feasibility_cb (flux_t *h,
                             "jobspec", &jobspec) < 0)
         goto err;
     if (json_unpack (jobspec,
-                     "{s?{s?{s?o}}}",
+                     "{s:{s?{s?o}}}",
                      "attributes",
                      "system",
                      "constraints", &constraints) < 0)

src/shell/batch.c

@@ -213,7 +213,7 @@ static int batch_init (flux_plugin_t *p,
         return shell_log_errno ("failed to unpack jobspec");
     json_error_t err;
     if (json_unpack_ex (jobspec, &err, 0,
-                        "{s:{s:{s?o}}}",
+                        "{s:{s?{s?o}}}",
                         "attributes",
                           "system",
                             "batch", &batch) < 0) {

src/shell/files.c

@@ -83,7 +83,7 @@ static int files_init (flux_plugin_t *p,
         return shell_log_errno ("flux_shell_getenv");
 
     if (flux_shell_info_unpack (shell,
-                               "{s:{s:{s:{s?o}}}}",
+                               "{s:{s:{s?{s?o}}}}",
                                "jobspec",
                                  "attributes",
                                    "system",

src/shell/jobspec.c

@@ -235,7 +235,7 @@ struct jobspec *jobspec_parse (const char *jobspec, json_error_t *error)
      *  json_t * objects)
      */
     if (json_unpack_ex (job->jobspec, error, 0,
-                        "{s:i s:o s:o s:{s:{s?:s s?:O s?:{s?:O}}}}",
+                        "{s:i s:o s:o s:{s?{s?:s s?:O s?:{s?:O}}}}",
                         "version", &job->version,
                         "resources", &resources,
                         "tasks", &tasks,

t/job-manager/plugins/dependency-test.c

@@ -132,7 +132,7 @@ static int depend_cb (flux_plugin_t *p,
 
     if (flux_plugin_arg_unpack (args,
                                 FLUX_PLUGIN_ARG_IN,
-                                "{s:I s:{s:{s:{s?s}}}}",
+                                "{s:I s:{s:{s?{s?s}}}}",
                                 "id", &id,
                                 "jobspec",
                                 "attributes",