Check cJSON_IsNull when the data type is datetime (OpenAPITools#13884)

Author: ityuhui

modules/openapi-generator/src/main/resources/C-libcurl/model-body.mustache

@@ -669,7 +669,7 @@ fail:
     {{/isDate}}
     {{#isDateTime}}
     {{^required}}if ({{{name}}}) { {{/required}}
-    if(!cJSON_IsString({{{name}}}))
+    if(!cJSON_IsString({{{name}}}) && !cJSON_IsNull({{{name}}}))
     {
     goto end; //DateTime
     }
@@ -893,7 +893,7 @@ fail:
         {{^required}}{{{name}}} ? {{/required}}strdup({{{name}}}->valuestring){{^required}} : NULL{{/required}}{{^-last}},{{/-last}}
         {{/isDate}}
         {{#isDateTime}}
-        {{^required}}{{{name}}} ? {{/required}}strdup({{{name}}}->valuestring){{^required}} : NULL{{/required}}{{^-last}},{{/-last}}
+        {{^required}}{{{name}}} && !cJSON_IsNull({{{name}}}) ? {{/required}}strdup({{{name}}}->valuestring){{^required}} : NULL{{/required}}{{^-last}},{{/-last}}
         {{/isDateTime}}
         {{/isPrimitiveType}}
         {{/isContainer}}

samples/client/petstore/c/model/order.c

@@ -150,7 +150,7 @@ order_t *order_parseFromJSON(cJSON *orderJSON){
     // order->ship_date
     cJSON *ship_date = cJSON_GetObjectItemCaseSensitive(orderJSON, "shipDate");
     if (ship_date) { 
-    if(!cJSON_IsString(ship_date))
+    if(!cJSON_IsString(ship_date) && !cJSON_IsNull(ship_date))
     {
     goto end; //DateTime
     }
@@ -181,7 +181,7 @@ order_t *order_parseFromJSON(cJSON *orderJSON){
         id ? id->valuedouble : 0,
         pet_id ? pet_id->valuedouble : 0,
         quantity ? quantity->valuedouble : 0,
-        ship_date ? strdup(ship_date->valuestring) : NULL,
+        ship_date && !cJSON_IsNull(ship_date) ? strdup(ship_date->valuestring) : NULL,
         status ? statusVariable : -1,
         complete ? complete->valueint : 0
         );