Fixed: [Behaviour of Empty LIST Input in RESTCONF JSON #166](https://github.com/clicon/clixon/issues/166)

CHANGELOG.md

@@ -70,6 +70,7 @@ Users may have to change how they access the system
 
 ### Corrected Bugs
 
+* Fixed: [Behaviour of Empty LIST Input in RESTCONF JSON #166](https://github.com/clicon/clixon/issues/166)
 * Netconf split lines input (input fragments) fixed
   * Netconf input split on several lines, eg using stdin: "<a>\nfoo</a>]]>]]>" could under some circumstances be split so that only "</a>]]>]]>" be properly processed. This could also happen to a socket receiving a sub-string and then after a delay receive the rest.
   * Fixed by storing residue and add that to the input string if later input is received on the same socket.

lib/src/clixon_json_parse.y

@@ -133,6 +133,13 @@ object.
 
 #include "clixon_json_parse.h"
 
+/* Enable for debugging, steals some cycles otherwise */
+#if 0
+#define _PARSE_DEBUG(s) clicon_debug(1,(s))
+#else
+#define _PARSE_DEBUG(s)
+#endif
+
 extern int clixon_json_parseget_lineno  (void);
 
 /* 
@@ -239,56 +246,63 @@ json_current_body(clixon_json_yacc *jy,
     return retval;
  }
 
+static int
+json_empty_list(clixon_json_yacc *jy)
+{
+    xml_rm(jy->jy_current);
+    xml_free(jy->jy_current);
+    jy->jy_current = NULL;
+    return 0;
+}
 
 %} 
  
 %%
 
-
-
 /*
 */
 
  /* top: json -> value is also possible */
-json          : value J_EOF { clicon_debug(3,"json->object"); YYACCEPT; } 
+json          : value J_EOF { _PARSE_DEBUG("json->value"); YYACCEPT; } 
               ;
 
-value         : J_TRUE  { json_current_body(_JY, "true");}
+value         : J_TRUE  { json_current_body(_JY, "true");       _PARSE_DEBUG("value->TRUE");}
-              | J_FALSE { json_current_body(_JY, "false");}
+              | J_FALSE { json_current_body(_JY, "false");      _PARSE_DEBUG("value->FALSE");}
-              | J_NULL  { json_current_body(_JY, NULL);}
+              | J_NULL  { json_current_body(_JY, NULL);         _PARSE_DEBUG("value->NULL");}
-              | object
+              | object                                        { _PARSE_DEBUG("value->object"); }
-	      | array
+	      | array                                         { _PARSE_DEBUG("value->array"); }
-              | number  { json_current_body(_JY, $1); free($1);}
+              | number  { json_current_body(_JY, $1); free($1); _PARSE_DEBUG("value->number");}
-              | string  { json_current_body(_JY, $1); free($1);}
+              | string  { json_current_body(_JY, $1); free($1); _PARSE_DEBUG("value->string");}
 
               ;
 
-object        : '{' '}' { clicon_debug(3,"object->{}");}
+object        : '{' '}'         { _PARSE_DEBUG("object->{}"); _PARSE_DEBUG("object->{}");}
-              | '{' objlist '}' { clicon_debug(3,"object->{ objlist }");}
+              | '{' objlist '}' { _PARSE_DEBUG("object->{ objlist }"); _PARSE_DEBUG("object->{ objlist }");}
               ;
 
-objlist       : pair  { clicon_debug(3,"objlist->pair");}
+objlist       : pair             { _PARSE_DEBUG("objlist->pair");}
-              | objlist ',' pair { clicon_debug(3,"objlist->objlist , pair");}
+              | objlist ',' pair { _PARSE_DEBUG("objlist->objlist , pair");}
               ;
 
 pair          : string { json_current_new(_JY, $1);free($1);} ':' 
-                value { json_current_pop(_JY);}{ clicon_debug(3,"pair->string : value");}
+                value { json_current_pop(_JY);}{ _PARSE_DEBUG("pair->string : value");}
               ;
 
-array         : '[' ']'
+array         : '[' ']'           { json_empty_list(_JY); _PARSE_DEBUG("array->[]"); }
-              | '[' valuelist ']'
+              | '[' valuelist ']' { _PARSE_DEBUG("array->[ valuelist ]"); }
               ;
 
-valuelist     : value 
+valuelist     : value             { _PARSE_DEBUG("valuelist->value"); }
-              | valuelist { if (json_current_clone(_JY)< 0) _YYERROR("stack?");} ',' value 
+              | valuelist { if (json_current_clone(_JY)< 0) _YYERROR("stack?");}
+                ',' value         { _PARSE_DEBUG("valuelist->valuelist , value");}
               ;
 
 /* quoted string */
-string        : J_DQ ustring J_DQ {  clicon_debug(3,"string->\" ustring \"");$$=$2; }
+string        : J_DQ ustring J_DQ { _PARSE_DEBUG("string->\" ustring \"");$$=$2; }
-              | J_DQ J_DQ {  clicon_debug(3,"string->\" ustring \"");$$=strdup(""); }
+              | J_DQ J_DQ         { _PARSE_DEBUG("string->\" \"");$$=strdup(""); }
               ;
 
-/* unquoted string */
+/* unquoted string: can be optimized by reading whole string in lex */
 ustring       : ustring J_CHAR 
                      {
 			 int len = strlen($1);

test/test_json.sh

@@ -59,9 +59,14 @@ expecteofx "$clixon_util_json" 0 '{"foo": -23}' "<foo>-23</foo>"
 new "json parse to json" # should be {"foo": -23}
 expecteofx "$clixon_util_json -j" 0 '{"foo": -23}' '{"foo":"-23"}'
 
-new "json parse list xml"
+new "json parse list to xml"
 expecteofx "$clixon_util_json" 0 '{"a":[0,1,2,3]}' "<a>0</a><a>1</a><a>2</a><a>3</a>"
 
+# See test_restconf.sh
+new "json parse empty list to xml"
+expecteofx "$clixon_util_json" 0 '{"a":[]}' "
+" # XXX empty
+
 new "json parse list json" # should be {"a":[0,1,2,3]}
 expecteofx "$clixon_util_json -j" 0 '{"a":[0,1,2,3]}' '{"a":"0"}{"a":"1"}{"a":"2"}{"a":"3"}'
 

test/test_restconf.sh

@@ -264,6 +264,10 @@ testrun()
     new "restconf Add subtree eth/0/0 to datastore using POST"
     expectpart "$(curl $CURLOPTS -X POST -H "Accept: application/yang-data+json" -H "Content-Type: application/yang-data+json" -d '{"ietf-interfaces:interfaces":{"interface":{"name":"eth/0/0","type":"clixon-example:eth","enabled":true}}}' $proto://$addr/restconf/data)" 0 'HTTP/1.1 201 Created' "Location: $proto://$addr/restconf/data/ietf-interfaces:interfaces"
 
+# See test_json.sh
+    new "restconf empty list"
+    expectpart "$(curl $CURLOPTS -X POST -H "Accept: application/yang-data+json" -H "Content-Type: application/yang-data+json" -d '{"clixon-example:route":{"ipv4":[]}}' $proto://$addr/restconf/data)" 0 'HTTP/1.1 201 Created' "Location: $proto://$addr/restconf/data/clixon-example:route"
+
     new "restconf Re-add subtree eth/0/0 which should give error"
     expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" -d '{"ietf-interfaces:interfaces":{"interface":{"name":"eth/0/0","type":"clixon-example:eth","enabled":true}}}' $proto://$addr/restconf/data)" 0 '{"ietf-restconf:errors":{"error":{"error-type":"application","error-tag":"data-exists","error-severity":"error","error-message":"Data already exists; cannot create new resource"}}}'