Fail Vulkan surface creation if window has context

OpenGL / OpenGL ES cannot share presentation on a window with Vulkan.
This adds an error to `glfwCreateWindowSurface` when it is called on a
window without the GLFW_CLIENT_API hint set to GLFW_NO_API.  This
prevents undefined bahevior and hard to debug crashes.

Fixes #1194.
Closes #1205.

README.md

@@ -178,6 +178,8 @@ information on what to include when reporting a bug.
 - Added `GLFW_OSMESA_CONTEXT_API` for creating OpenGL contexts with
   [OSMesa](https://www.mesa3d.org/osmesa.html) (#281)
 - Added `GenerateMappings.cmake` script for updating gamepad mappings
+- Made `glfwCreateWindowSurface` emit an error when the window has a context
+  (#1194,#1205)
 - Deprecated window parameter of clipboard string functions
 - Deprecated charmods callback
 - Removed `GLFW_USE_RETINA` compile-time option
@@ -442,6 +444,7 @@ skills.
  - Ricardo Vieira
  - Nicholas Vitovitch
  - Simon Voordouw
+ - Corentin Wallez
  - Torsten Walluhn
  - Patrick Walton
  - Xo Wang

docs/vulkan.dox

@@ -230,6 +230,10 @@ if (err)
 }
 @endcode
 
+If an OpenGL or OpenGL ES context was created on the window, the context has
+ownership of the presentation on the window and a Vulkan surface cannot be
+created.
+
 It is your responsibility to destroy the surface.  GLFW does not destroy it for
 you.  Call `vkDestroySurfaceKHR` function from the same extension to destroy it.
 

include/GLFW/glfw3.h

@@ -5441,6 +5441,11 @@ GLFWAPI int glfwGetPhysicalDevicePresentationSupport(VkInstance instance, VkPhys
  *  glfwGetRequiredInstanceExtensions to check what instance extensions are
  *  required.
  *
+ *  The window surface cannot be shared with another API so the window must
+ *  have been created with the [client api hint](@ref GLFW_CLIENT_API_attrib)
+ *  set to `GLFW_NO_API` otherwise it generates a @ref GLFW_INVALID_VALUE error
+ *  and returns `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`.
+ *
  *  The window surface must be destroyed before the specified Vulkan instance.
  *  It is the responsibility of the caller to destroy the window surface.  GLFW
  *  does not destroy it for you.  Call `vkDestroySurfaceKHR` to destroy the
@@ -5456,7 +5461,7 @@ GLFWAPI int glfwGetPhysicalDevicePresentationSupport(VkInstance instance, VkPhys
  *  [error](@ref error_handling) occurred.
  *
  *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED, @ref
- *  GLFW_API_UNAVAILABLE and @ref GLFW_PLATFORM_ERROR.
+ *  GLFW_API_UNAVAILABLE, @ref GLFW_PLATFORM_ERROR and @ref GLFW_INVALID_VALUE
  *
  *  @remark If an error occurs before the creation call is made, GLFW returns
  *  the Vulkan error code most appropriate for the error.  Appropriate use of

src/vulkan.c

@@ -317,6 +317,13 @@ GLFWAPI VkResult glfwCreateWindowSurface(VkInstance instance,
         return VK_ERROR_EXTENSION_NOT_PRESENT;
     }
 
+    if (window->context.client != GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_INVALID_VALUE,
+                        "Vulkan: Window surface creation requires the window to have the client API set to GLFW_NO_API");
+        return VK_ERROR_NATIVE_WINDOW_IN_USE_KHR;
+    }
+
     return _glfwPlatformCreateWindowSurface(instance, window, allocator, surface);
 }