make destroy_pval able to handle a NULL value

(the warning should be removed);
define a 'elements_block' rule to simplify some other rules
removing duplicated code - runtests seems happy with this.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@23613 65c4cc65-6c06-0410-ace0-fbb531ad65f3

pbx/ael/ael.y

@@ -116,6 +116,7 @@ static pval *update_last(pval *, YYLTYPE *);
 %type <pval>file
 /* XXX lr changes */
 %type <pval>opt_else
+%type <pval>elements_block
 
 %type <str>opt_word
 %type <str>word_or_default
@@ -159,6 +160,7 @@ static pval *update_last(pval *, YYLTYPE *);
 		ignorepat element elements arglist global_statement
 		global_statements globals macro context object objects
 		opt_else
+		elements_block
 
 %destructor { free($$);}  word word_list goto_word word3_list includedname opt_word word_or_default
 
@@ -193,21 +195,14 @@ word_or_default : word { $$ = $1; }
 	| KW_DEFAULT { $$ = strdup("default"); }
 	;
 
-context : KW_CONTEXT word_or_default LC elements RC {
-		$$ = npval2(PV_CONTEXT, &@1, &@5);
+context : KW_CONTEXT word_or_default elements_block {
+		$$ = npval2(PV_CONTEXT, &@1, &@3);
 		$$->u1.str = $2;
-		$$->u2.statements = $4; }
-	| KW_CONTEXT word_or_default LC RC /* empty context OK */ {
+		$$->u2.statements = $3; }
+	| KW_ABSTRACT KW_CONTEXT word_or_default elements_block {
 		$$ = npval2(PV_CONTEXT, &@1, &@4);
-		$$->u1.str = $2; }
-	| KW_ABSTRACT KW_CONTEXT word_or_default LC elements RC {
-		$$ = npval2(PV_CONTEXT, &@1, &@6);
-		$$->u1.str = $3;
-		$$->u2.statements = $5;
-		$$->u3.abstract = 1; }
-	| KW_ABSTRACT KW_CONTEXT word_or_default LC RC /* empty context OK */ {
-		$$ = npval2(PV_CONTEXT, &@1, &@5);
 		$$->u1.str = $3;
+		$$->u2.statements = $4;
 		$$->u3.abstract = 1; }
 	;
 
@@ -254,6 +249,10 @@ arglist : word {
 	| arglist error {$$=$1;}
 	;
 
+elements_block : LC RC	{ $$ = NULL; }
+	| LC elements RC { $$ = $2; }
+	;
+
 elements : element { $$=$1;}
 	| error {$$=0;}
 	| elements element { if ( $1 && $2 ) {$$=$1; linku1($$,$2);}

pbx/pbx_ael.c

@@ -3554,6 +3554,11 @@ STD_MOD(MOD_1 | NO_USECOUNT, reload, NULL, NULL);
 
 void destroy_pval_item(pval *item)
 {
+	if (item == NULL) {
+		ast_log(LOG_WARNING, "null item\n");
+		return;
+	}
+
 	if (item->filename)
 		free(item->filename);