From 18393ea5cbdb164103d048198ad146b685214fa2 Mon Sep 17 00:00:00 2001
From: vittorioromeo <mail@vittorioromeo.com>
Date: Mon, 20 Jan 2025 16:24:04 +0100
Subject: [PATCH] Add non-`const` overload of `Event::visit`

---
 include/SFML/Window/Event.hpp      | 11 +++++++
 include/SFML/Window/Event.inl      |  8 +++++
 include/SFML/Window/WindowBase.inl |  2 +-
 test/Window/Event.test.cpp         | 47 ++++++++++++++++++++++++------
 4 files changed, 58 insertions(+), 10 deletions(-)

diff --git a/include/SFML/Window/Event.hpp b/include/SFML/Window/Event.hpp
index 28bd4cf12..df2972b6a 100644
--- a/include/SFML/Window/Event.hpp
+++ b/include/SFML/Window/Event.hpp
@@ -338,6 +338,17 @@ public:
     template <typename TEventSubtype>
     [[nodiscard]] const TEventSubtype* getIf() const;
 
+    ////////////////////////////////////////////////////////////
+    /// \brief Apply a visitor to the event
+    ///
+    /// \param visitor The visitor to apply
+    ///
+    /// \return The result of applying the visitor to the event
+    ///
+    ////////////////////////////////////////////////////////////
+    template <typename T>
+    decltype(auto) visit(T&& visitor);
+
     ////////////////////////////////////////////////////////////
     /// \brief Apply a visitor to the event
     ///
diff --git a/include/SFML/Window/Event.inl b/include/SFML/Window/Event.inl
index 8046a4bb3..daabd2fd3 100644
--- a/include/SFML/Window/Event.inl
+++ b/include/SFML/Window/Event.inl
@@ -78,6 +78,14 @@ const TEventSubtype* Event::getIf() const
 }
 
 
+////////////////////////////////////////////////////////////
+template <typename T>
+decltype(auto) Event::visit(T&& visitor)
+{
+    return std::visit(std::forward<T>(visitor), m_data);
+}
+
+
 ////////////////////////////////////////////////////////////
 template <typename T>
 decltype(auto) Event::visit(T&& visitor) const
diff --git a/include/SFML/Window/WindowBase.inl b/include/SFML/Window/WindowBase.inl
index 19a939564..2c5c89c7b 100644
--- a/include/SFML/Window/WindowBase.inl
+++ b/include/SFML/Window/WindowBase.inl
@@ -68,7 +68,7 @@ void WindowBase::handleEvents(Ts&&... handlers) // NOLINT(cppcoreguidelines-miss
     // NOLINTNEXTLINE(misc-const-correctness)
     priv::OverloadSet overloadSet{std::forward<Ts>(handlers)..., [](const priv::DelayOverloadResolution&) { /* ignore */ }};
 
-    while (const std::optional event = pollEvent())
+    while (std::optional event = pollEvent())
         event->visit(overloadSet);
 }
 
diff --git a/test/Window/Event.test.cpp b/test/Window/Event.test.cpp
index 11d9ee3e4..9977f3618 100644
--- a/test/Window/Event.test.cpp
+++ b/test/Window/Event.test.cpp
@@ -9,17 +9,22 @@ namespace
 {
 struct
 {
-    std::string_view operator()(const sf::Event::Closed&) const
+    std::string_view operator()(sf::Event::Closed&) const
     {
-        return "Closed";
+        return "Closed (non-const)";
     }
 
-    std::string_view operator()(const sf::Event::Resized&) const
+    std::string_view operator()(const sf::Event::Closed&) const
+    {
+        return "Closed (const)";
+    }
+
+    std::string_view operator()(sf::Event::Resized&) const
     {
         return "Resized";
     }
 
-    std::string_view operator()(const sf::Event::KeyPressed&) const
+    std::string_view operator()(sf::Event::KeyPressed) const
     {
         return "KeyPressed";
     }
@@ -306,10 +311,34 @@ TEST_CASE("[Window] sf::Event")
 
     SECTION("visit()")
     {
-        CHECK(sf::Event(sf::Event::Closed{}).visit(visitor) == "Closed");
-        CHECK(sf::Event(sf::Event::Resized{}).visit(visitor) == "Resized");
-        CHECK(sf::Event(sf::Event::FocusLost{}).visit(visitor) == "Other");
-        CHECK(sf::Event(sf::Event::FocusGained{}).visit(visitor) == "Other");
-        CHECK(sf::Event(sf::Event::KeyPressed{}).visit(visitor) == "KeyPressed");
+        SECTION("Non-const")
+        {
+            sf::Event closed = sf::Event::Closed{};
+            CHECK(closed.visit(visitor) == "Closed (non-const)");
+
+            sf::Event resized = sf::Event::Resized{};
+            CHECK(resized.visit(visitor) == "Resized");
+
+            sf::Event keyPressed = sf::Event::KeyPressed{};
+            CHECK(keyPressed.visit(visitor) == "KeyPressed");
+
+            sf::Event focusLost = sf::Event::FocusLost{};
+            CHECK(focusLost.visit(visitor) == "Other");
+        }
+
+        SECTION("Const")
+        {
+            const sf::Event closed = sf::Event::Closed{};
+            CHECK(closed.visit(visitor) == "Closed (const)");
+
+            const sf::Event resized = sf::Event::Resized{};
+            CHECK(resized.visit(visitor) == "Other"); // Cannot use non-const reference callback
+
+            const sf::Event keyPressed = sf::Event::KeyPressed{};
+            CHECK(keyPressed.visit(visitor) == "KeyPressed");
+
+            const sf::Event focusLost = sf::Event::FocusLost{};
+            CHECK(focusLost.visit(visitor) == "Other");
+        }
     }
 }