Change: Don't handle 'missing' string parameters as 0. (#11673)

If not enough parameters are supplied for a string, then a value of 0 was used, which could result in incorrect information being displayed.

Instead, throw an exception and include an error in the string.

src/strings.cpp

@@ -81,15 +81,13 @@ StringParameter *StringParameters::GetNextParameterPointer()
 {
 	assert(this->next_type == 0 || (SCC_CONTROL_START <= this->next_type && this->next_type <= SCC_CONTROL_END));
 	if (this->offset >= this->parameters.size()) {
-		Debug(misc, 0, "Trying to read invalid string parameter");
-		return nullptr;
+		throw std::out_of_range("Trying to read invalid string parameter");
 	}
 
 	auto &param = this->parameters[this->offset++];
 	if (param.type != 0 && param.type != this->next_type) {
-		Debug(misc, 0, "Trying to read string parameter with wrong type");
 		this->next_type = 0;
-		return nullptr;
+		throw std::out_of_range("Trying to read string parameter with wrong type");
 	}
 	param.type = this->next_type;
 	this->next_type = 0;
@@ -903,6 +901,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 	str_stack.push(str_arg);
 
 	for (;;) {
+		try {
 			while (!str_stack.empty() && (b = Utf8Consume(&str_stack.top())) == '\0') {
 				str_stack.pop();
 			}
@@ -1105,7 +1104,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 
 				case SCC_RAW_STRING_POINTER: { // {RAW_STRING}
 					const char *raw_string = args.GetNextParameterString();
-				/* raw_string can be(come) nullptr when the parameter is out of range and 0 is returned instead. */
+					/* raw_string can be nullptr. */
 					if (raw_string == nullptr) {
 						builder += "(invalid RAW_STRING parameter)";
 						break;
@@ -1631,6 +1630,10 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 					builder.Utf8Encode(b);
 					break;
 			}
+		} catch (std::out_of_range &e) {
+			Debug(misc, 0, "FormatString: {}", e.what());
+			builder += "(invalid parameter)";
+		}
 	}
 }
 

src/strings_internal.h

@@ -95,7 +95,7 @@ public:
 	T GetNextParameter()
 	{
 		auto ptr = GetNextParameterPointer();
-		return static_cast<T>(ptr == nullptr ? 0 : ptr->data);
+		return static_cast<T>(ptr->data);
 	}
 
 	/**
@@ -107,7 +107,6 @@ public:
 	const char *GetNextParameterString()
 	{
 		auto ptr = GetNextParameterPointer();
-		if (ptr == nullptr) return nullptr;
 		return ptr->string != nullptr ? ptr->string->c_str() : ptr->string_view;
 	}