fix: stabilize runtime follow-up regressions

src/lib/mysql-connector.cpp

@@ -3,16 +3,28 @@
 #include <stdlib.h>
 #include "mysql-connector.h"
 
+static void mysql_register_request_connection(MySQL* db)
+{
+	if(!context || !db)
+		return;
+	auto& connections = context->resources.mysql_connections;
+	if(std::find(connections.begin(), connections.end(), (void*)db) == connections.end())
+		connections.push_back(db);
+}
+
 bool MySQL::connect(String host, String username, String password)
 {
+	// Register regardless of outcome: tracking is about the wrapper's
+	// lifetime, not the connection's. disconnect()/~MySQL() unregister.
+	mysql_register_request_connection(this);
 	//switch_to_system_alloc();
 	connection = mysql_init(NULL);
 	if (connection == NULL)
 	{
-		auto e = mysql_error((MYSQL*)connection);
-		fprintf(stderr, "%s\n", e);
+		fprintf(stderr, "mysql_init failed\n");
 		//switch_to_arena(context->mem);
-		statement_info.assign(e);
+		_preload_next_error_code = CR_OUT_OF_MEMORY;
+		statement_info = "mysql_init failed";
 		return(false);
 	}
 
@@ -21,9 +33,11 @@ bool MySQL::connect(String host, String username, String password)
 	{
 		auto e = mysql_error((MYSQL*)connection);
 		fprintf(stderr, "%s\n", e);
-		mysql_close((MYSQL*)connection);
-		//switch_to_arena(context->mem);
+		_preload_next_error_code = CR_UNKNOWN_ERROR;
 		statement_info.assign(e);
+		mysql_close((MYSQL*)connection);
+		connection = NULL;
+		//switch_to_arena(context->mem);
 		return(false);
 	}
 
@@ -37,8 +51,6 @@ bool MySQL::connect(String host, String username, String password)
 	*/
 	//switch_to_arena(context->mem);
 	statement_info = String("connected");
-	if(context)
-		context->resources.mysql_connections.push_back(this);
 	return(true);
 }
 
@@ -192,6 +204,12 @@ DTree MySQL::query(String q)
 		statement_info = "mysql positional ? placeholders are not supported; use named :name placeholders";
 		return(DTree());
 	}
+	if(!connection)
+	{
+		_preload_next_error_code = CR_UNKNOWN_ERROR;
+		statement_info = "mysql connection is not open";
+		return(DTree());
+	}
 	_preload_next_error_code = mysql_query((MYSQL*)connection, q.c_str());
 	DTree result;
 	if(_preload_next_error_code == 0)
@@ -237,12 +255,8 @@ static bool mysql_has_unquoted_positional_placeholder(String query)
 
 DTree MySQL::query(String q, StringMap params)
 {
-	if(mysql_has_unquoted_positional_placeholder(q))
-	{
-		_preload_next_error_code = CR_UNKNOWN_ERROR;
-		statement_info = "mysql positional ? placeholders are not supported; use named :name placeholders";
-		return(DTree());
-	}
+	// Positional ? placeholders survive named substitution (values are always
+	// quoted by escape()), so the check in query(String) covers this path too.
 	return(query(
 		parse_query_parameters(q, params).c_str()
 	));
@@ -347,6 +361,8 @@ String MySQL::error()
 		_preload_next_error_code = 0;
 		return(p);
 	}
+	if(!connection)
+		return("");
 	const char* res = mysql_error((MYSQL*)connection);
 	if(res)
 	{