HPCC-9869 check id parameter to getPckageMapById

Signed-off-by: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>

common/workunit/package.cpp

@@ -212,6 +212,8 @@ extern WORKUNIT_API IHpccPackageSet *createPackageSet(const char *process)
 
 extern WORKUNIT_API IPropertyTree * getPackageMapById(const char * id, bool readonly)
 {
+    if (!id || !*id)
+        return NULL;
     StringBuffer xpath;
     xpath.append("/PackageMaps/PackageMap[@id=\"").append(id).append("\"]");
     Owned<IRemoteConnection> conn = querySDS().connect(xpath.str(), myProcessSession(), readonly ? RTM_LOCK_READ : RTM_LOCK_WRITE, SDS_LOCK_TIMEOUT);
@@ -222,6 +224,8 @@ extern WORKUNIT_API IPropertyTree * getPackageMapById(const char * id, bool read
 
 extern WORKUNIT_API IPropertyTree * getPackageMapById(const char *target, const char * id, bool readonly)
 {
+    if (!id || !*id)
+        return NULL;
     if (target && *target)
     {
         VStringBuffer xpath("/PackageMaps/PackageMap[@id='%s::%s']", target, id);