From bfa24c9f2d0b640ccc27cfbd221849b153f6a5a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Camilla=20L=C3=B6wy?= <elmindreda@elmindreda.org>
Date: Wed, 13 Dec 2023 15:27:30 +0100
Subject: [PATCH] Fix glfwGetKeyName incorrectly emitting error

glfwGetKeyName emitted GLFW_INVALID_VALUE when passed GLFW_KEY_UNKNOWN
and any scancode not associated with a key token on that platform.

This causes physical keys with no associated key token to emit
GLFW_INVALID_VALUE when the key and scancode are passed directly from
the key event to glfwGetKeyName.  This breaks the promise made in the
reference documentation for glfwGetKeyName.

This commit removes that error for the whole range of valid scancodes.

Fixes #1785
Fixes #2214

This was adapted to 3.3-stable from
86bf5698ecfdbe783135ffaf72972a8c562c0fdf.
---
 CONTRIBUTORS.md    |  1 +
 README.md          |  2 ++
 src/cocoa_window.m |  5 +++--
 src/win32_window.c | 11 ++++++++---
 src/wl_window.c    |  6 ++++--
 src/x11_window.c   |  6 ++++--
 6 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index b04aef2b..367ab358 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -255,6 +255,7 @@ video tutorials.
  - Jay Weisskopf
  - Frank Wille
  - Richard A. Wilkes
+ - Andy Williams
  - Tatsuya Yatagawa
  - Ryogo Yoshimura
  - Rácz Zalán
diff --git a/README.md b/README.md
index ed88f277..092445f6 100644
--- a/README.md
+++ b/README.md
@@ -123,6 +123,8 @@ information on what to include when reporting a bug.
 
 ## Changelog
 
+ - Bugfix: `glfwGetKeyName` emitted `GLFW_INVALID_VALUE` for scancodes with no
+   key token (#1785,#2214)
  - [Wayland] Bugfix: Terminating the library before showing a window could segfault
  - [Linux] Bugfix: `regfree´ was called on invalid data (#2464)
 
diff --git a/src/cocoa_window.m b/src/cocoa_window.m
index 2d065c35..d7e89cf3 100644
--- a/src/cocoa_window.m
+++ b/src/cocoa_window.m
@@ -1635,14 +1635,15 @@ const char* _glfwPlatformGetScancodeName(int scancode)
 {
     @autoreleasepool {
 
-    if (scancode < 0 || scancode > 0xff ||
-        _glfw.ns.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    if (scancode < 0 || scancode > 0xff)
     {
         _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
     const int key = _glfw.ns.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
 
     UInt32 deadKeyState = 0;
     UniChar characters[4];
diff --git a/src/win32_window.c b/src/win32_window.c
index 3c22ab16..5aecaadd 100644
--- a/src/win32_window.c
+++ b/src/win32_window.c
@@ -2191,14 +2191,19 @@ void _glfwPlatformSetCursorMode(_GLFWwindow* window, int mode)
 
 const char* _glfwPlatformGetScancodeName(int scancode)
 {
-    if (scancode < 0 || scancode > (KF_EXTENDED | 0xff) ||
-        _glfw.win32.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    int key;
+
+    if (scancode < 0 || scancode > (KF_EXTENDED | 0xff))
     {
         _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
-    return _glfw.win32.keynames[_glfw.win32.keycodes[scancode]];
+    key = _glfw.win32.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
+
+    return _glfw.win32.keynames[key];
 }
 
 int _glfwPlatformGetKeyScancode(int key)
diff --git a/src/wl_window.c b/src/wl_window.c
index a077c15a..4e51e186 100644
--- a/src/wl_window.c
+++ b/src/wl_window.c
@@ -2575,8 +2575,7 @@ void _glfwPlatformSetCursorMode(_GLFWwindow* window, int mode)
 
 const char* _glfwPlatformGetScancodeName(int scancode)
 {
-    if (scancode < 0 || scancode > 255 ||
-        _glfw.wl.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    if (scancode < 0 || scancode > 255)
     {
         _glfwInputError(GLFW_INVALID_VALUE,
                         "Wayland: Invalid scancode %i",
@@ -2585,6 +2584,9 @@ const char* _glfwPlatformGetScancodeName(int scancode)
     }
 
     const int key = _glfw.wl.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
+
     const xkb_keycode_t keycode = scancode + 8;
     const xkb_layout_index_t layout =
         xkb_state_key_get_layout(_glfw.wl.xkb.state, keycode);
diff --git a/src/x11_window.c b/src/x11_window.c
index 9bd29e34..ef02f139 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -2930,14 +2930,16 @@ const char* _glfwPlatformGetScancodeName(int scancode)
     if (!_glfw.x11.xkb.available)
         return NULL;
 
-    if (scancode < 0 || scancode > 0xff ||
-        _glfw.x11.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    if (scancode < 0 || scancode > 0xff)
     {
         _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
     const int key = _glfw.x11.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
+
     const KeySym keysym = XkbKeycodeToKeysym(_glfw.x11.display,
                                              scancode, _glfw.x11.xkb.group, 0);
     if (keysym == NoSymbol)