Fix attachment validation bug

src/libANGLE/validationES.cpp

@@ -1446,7 +1446,9 @@ bool ValidateAttachmentTarget(gl::Context *context, GLenum attachment)
 
         if (colorAttachment >= context->getCaps().maxColorAttachments)
         {
-            context->handleError(InvalidValue());
+            context->handleError(
+                InvalidOperation()
+                << "attachment index cannot be greater or equal to MAX_COLOR_ATTACHMENTS.");
             return false;
         }
     }

src/tests/gl_tests/FramebufferTest.cpp

@@ -478,6 +478,26 @@ TEST_P(FramebufferTest_ES3, TextureAttachmentMipLevels)
     ExpectFramebufferCompleteOrUnsupported(GL_FRAMEBUFFER);
 }
 
+// Test that passing an attachment COLOR_ATTACHMENTm where m is equal to MAX_COLOR_ATTACHMENTS
+// generates an INVALID_OPERATION.
+// OpenGL ES Version 3.0.5 (November 3, 2016), 4.4.2.4 Attaching Texture Images to a Framebuffer, p.
+// 208
+TEST_P(FramebufferTest_ES3, ColorAttachmentIndexOutOfBounds)
+{
+    GLFramebuffer framebuffer;
+    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer.get());
+
+    GLint maxColorAttachments = 0;
+    glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS, &maxColorAttachments);
+    GLenum attachment = static_cast<GLenum>(maxColorAttachments + GL_COLOR_ATTACHMENT0);
+
+    GLTexture texture;
+    glBindTexture(GL_TEXTURE_2D, texture.get());
+    glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA32F, 1, 1);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, attachment, GL_TEXTURE_2D, texture.get(), 0);
+    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+}
+
 ANGLE_INSTANTIATE_TEST(FramebufferTest_ES3, ES3_D3D11(), ES3_OPENGL(), ES3_OPENGLES());
 
 class FramebufferTest_ES31 : public ANGLETest