Is textureSize(samplerExternalOES, int) missing in desktop mesa 19.1.7 implementation?

[Martin Stransky]

Hi guys,

while implementing WebRender Wayland backend in Firefox [1] I hit a 
strange bug.

Although GL_OES_EGL_image_external_essl3 extension is supported on my 
system (Fedora 30 / Intel Skylake GT2 / OpenGL ES 3.2 Mesa 19.1.7) I'm 
getting this error from a sample fragment shader:

Error: compiling fragment: 0:7(2): error: no matching function for call 
to `textureSize(samplerExternalOES, int)'; candidates are:

...
...

I checked that GL_OES_EGL_image_external_essl3 is explicitly enabled in 
my shader, I even installed my own mesa debug build and stepped by gdb 
into shader compilation routines but it looks like that textureSize() 
implementation for samplerExternalOES is just missing, although its' 
explicitly mentioned by
GL_OES_EGL_image_external_essl3 spec.

Can anyone confirm that or am I just doing something wrong?

Thanks,
ma.

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1583731

-- 
Martin Stransky
Software Engineer / Red Hat, Inc