From 50ffc908e89bf984840c6f863b34d1115c49aeda Mon Sep 17 00:00:00 2001
From: Evil Eye <malusluminis@hotmail.com>
Date: Fri, 3 Oct 2025 17:21:52 +0200
Subject: [PATCH] Use vformat_to and add more tests

---
 apps/openmw_tests/mwscript/testscripts.cpp | 13 ++++++++++---
 components/interpreter/miscopcodes.hpp     | 15 ++++++++++-----
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/apps/openmw_tests/mwscript/testscripts.cpp b/apps/openmw_tests/mwscript/testscripts.cpp
index 1cc85e40ae..561a7bc3fa 100644
--- a/apps/openmw_tests/mwscript/testscripts.cpp
+++ b/apps/openmw_tests/mwscript/testscripts.cpp
@@ -138,6 +138,7 @@ set fVal to 12.34
 
 MessageBox "hello world"
 MessageBox "%.0f" fVal
+MessageBox "%.f" fVal
 MessageBox "a %03.0f b" fVal
 MessageBox "%+04.0f" fVal
 MessageBox "%+4.0f" fVal
@@ -153,6 +154,8 @@ MessageBox "%#.5g" fVal
 MessageBox "%-5g" fVal
 MessageBox "%- 5g" fVal
 
+MessageBox "%.1b" fVal
+
 End)mwscript";
 
     const std::string sIssue587 = R"mwscript(Begin stalresetScript
@@ -616,6 +619,7 @@ End)mwscript";
             constexpr std::array expected{
                 "hello world"sv,
                 "12"sv,
+                "12"sv,
                 "a 012 b"sv,
                 "+012"sv,
                 " +12"sv,
@@ -630,11 +634,14 @@ End)mwscript";
                 "12.340"sv,
                 "12.34"sv,
                 " 12.34"sv,
+
+                "b"sv,
             };
-            for (std::size_t i = 0; i < context.getMessages().size(); i++)
+            const std::vector<std::string>& output = context.getMessages();
+            EXPECT_EQ(expected.size(), output.size());
+            for (std::size_t i = 0; i < output.size(); i++)
             {
-                std::string_view message = context.getMessages()[i];
-                EXPECT_EQ(expected.at(i), message);
+                EXPECT_EQ(expected[i], output[i]);
             }
         }
         else
diff --git a/components/interpreter/miscopcodes.hpp b/components/interpreter/miscopcodes.hpp
index c8da745c41..05791617a6 100644
--- a/components/interpreter/miscopcodes.hpp
+++ b/components/interpreter/miscopcodes.hpp
@@ -46,7 +46,8 @@ namespace Interpreter
                     else
                         formatString += '>';
                     formatString += "{}}";
-                    mFormattedMessage += std::vformat(formatString, std::make_format_args(value, width));
+                    std::vformat_to(
+                        std::back_inserter(mFormattedMessage), formatString, std::make_format_args(value, width));
                 }
             }
             else
@@ -75,13 +76,17 @@ namespace Interpreter
                 formatString += '}';
                 const auto appendMessage = [&](auto value) {
                     if (width >= 0 && precision >= 0)
-                        mFormattedMessage += std::vformat(formatString, std::make_format_args(value, width, precision));
+                        std::vformat_to(std::back_inserter(mFormattedMessage), formatString,
+                            std::make_format_args(value, width, precision));
                     else if (width >= 0)
-                        mFormattedMessage += std::vformat(formatString, std::make_format_args(value, width));
+                        std::vformat_to(
+                            std::back_inserter(mFormattedMessage), formatString, std::make_format_args(value, width));
                     else if (precision >= 0)
-                        mFormattedMessage += std::vformat(formatString, std::make_format_args(value, precision));
+                        std::vformat_to(std::back_inserter(mFormattedMessage), formatString,
+                            std::make_format_args(value, precision));
                     else
-                        mFormattedMessage += std::vformat(formatString, std::make_format_args(value));
+                        std::vformat_to(
+                            std::back_inserter(mFormattedMessage), formatString, std::make_format_args(value));
                 };
                 if (placeholder == FloatPlaceholder)
                 {