GH-606: Output nulls into json data if a field isn't set

src/Val.cc

@@ -458,6 +458,10 @@ TableVal* Val::GetRecordFields()
 // This is a static method in this file to avoid including json.hpp in Val.h since it's huge.
 static ZeekJson BuildJSON(Val* val, bool only_loggable=false, RE_Matcher* re=new RE_Matcher("^_"))
 	{
+	// If the value wasn't set, return a nullptr. This will get turned into a 'null' in the json output.
+	if ( ! val )
+		return nullptr;
+
 	ZeekJson j;
 	BroType* type = val->Type();
 	switch ( type->Tag() )
@@ -2869,7 +2873,7 @@ int VectorVal::AddTo(Val* val, int /* is_first_init */) const
 Val* VectorVal::Lookup(unsigned int index) const
 	{
 	if ( index >= val.vector_val->size() )
-		return 0;
+		return nullptr;
 
 	return (*val.vector_val)[index];
 	}

src/threading/formatters/JSON.cc

@@ -73,6 +73,10 @@ threading::Value* JSON::ParseValue(const string& s, const string& name, TypeTag
 
 ZeekJson JSON::BuildJSON(Value* val, const string& name) const
 	{
+	// If the value wasn't set, return a nullptr. This will get turned into a 'null' in the json output.
+	if ( ! val->present )
+		return nullptr;
+
 	ZeekJson j;
 	switch ( val->type )
 		{

testing/btest/Baseline/scripts.base.frameworks.logging.ascii-json/ssh.log

@@ -1 +1 @@
-{"b":true,"i":-42,"e":"SSH::LOG","c":21,"p":123,"sn":"10.0.0.0/24","a":"1.2.3.4","d":3.14,"t":1215620010.54321,"iv":100.0,"s":"hurz","sc":[2,4,1,3],"ss":["BB","AA","CC"],"se":[],"vc":[10,20,30],"ve":[],"f":"SSH::foo\n{ \nif (0 < SSH::i) \n\treturn (Foo);\nelse\n\treturn (Bar);\n\n}"}
+{"b":true,"i":-42,"e":"SSH::LOG","c":21,"p":123,"sn":"10.0.0.0/24","a":"1.2.3.4","d":3.14,"t":1215620010.54321,"iv":100.0,"s":"hurz","sc":[2,4,1,3],"ss":["BB","AA","CC"],"se":[],"vc":[10,20,30],"ve":[],"vn":[0,null,2],"f":"SSH::foo\n{ \nif (0 < SSH::i) \n\treturn (Foo);\nelse\n\treturn (Bar);\n\n}"}

testing/btest/Baseline/scripts.base.utils.json/output

@@ -28,6 +28,7 @@ true
 ["1.2.3.4"]
 [[true,false]]
 [{"s":"test"}]
+[0,null,2]
 []
 [2,1]
 ["1.2.3.4"]

testing/btest/scripts/base/frameworks/logging/ascii-json.zeek

@@ -28,6 +28,7 @@ export {
 		se: set[string];
 		vc: vector of count;
 		ve: vector of string;
+		vn: vector of count;
 		f: function(i: count) : string;
 	} &log;
 }
@@ -47,6 +48,10 @@ event zeek_init()
 	local empty_set: set[string];
 	local empty_vector: vector of string;
 
+	local vector_with_null: vector of count;
+	vector_with_null[0] = 0;
+	vector_with_null[2] = 2;
+
 	Log::write(SSH::LOG, [
 		$b=T,
 		$i=-42,
@@ -64,6 +69,7 @@ event zeek_init()
 		$se=empty_set,
 		$vc=vector(10, 20, 30),
 		$ve=empty_vector,
+		$vn=vector_with_null,
 		$f=foo
 		]);
 }

testing/btest/scripts/base/utils/json.test

@@ -93,11 +93,15 @@ event zeek_init()
 	local ve3: vector of addr = vector(1.2.3.4);
 	local ve4: vector of set[bool] = vector(set(T, F));
 	local ve5: vector of myrec1 = vector(myrec1($s="test", $c=2));
+	local ve6: vector of count;
+	ve6[0] = 0;
+	ve6[2] = 2;
 	print to_json(ve1);
 	print to_json(ve2);
 	print to_json(ve3);
 	print to_json(ve4);
 	print to_json(ve5, T);
+	print to_json(ve6);
 
 	# Sets
 	local st1: set[count] = set();