datajson: handle case with multiple format

In some cases, the JSON array will contain different values type
and the wanted key may be absent from some items.

This patch fixes this use case by ignoring the data and just printing
a message if ever the no item have been found.

src/datajson.c

@@ -329,6 +329,7 @@ static int DatajsonLoadString(Dataset *set, char *json_key, char *array_key)
         fclose(fp);
     } else {
         json_t *json;
+        bool found = false;
 
         if (ParseJsonFile(set->load, &json, array_key) == -1)
             return -1;
@@ -339,10 +340,13 @@ static int DatajsonLoadString(Dataset *set, char *json_key, char *array_key)
             json_t *key = GetSubObjectByKey(value, json_key);
 
             if (key == NULL) {
-                FatalErrorOnInit("Can't find expected key '%s' in object", json_key);
+                /* ignore error as it can be a working mode where some entries
+                are not in the same format */
                 continue;
             }
 
+            found = true;
+
             const char *val = json_string_value(key);
 
             DataJsonType json = { .value = NULL, .len = 0 };
@@ -358,6 +362,12 @@ static int DatajsonLoadString(Dataset *set, char *json_key, char *array_key)
             }
         }
         json_decref(json);
+
+        if (found == false) {
+            FatalErrorOnInit(
+                    "No valid entries for key '%s' found in the file '%s'", json_key, set->load);
+            return -1;
+        }
     }
     THashConsolidateMemcap(set->hash);