ui/companion, ui/drivers/qt: link with no shader stack (fixes the Linux-qt-companion CI job)

The new Linux-qt-companion job failed to link: the runner has no
OpenGL/Vulkan dev packages, so with --disable-opengl/--disable-vulkan
the build had no shader stack at all (HAVE_GLSL, HAVE_SLANG, HAVE_CG,
HAVE_HLSL all off). menu_shader_get() is only compiled under one of
those, but two places gated on HAVE_MENU alone:

- ui/companion/companion_core.c called menu_shader_get() from its
  shader-parameter accessors -> undefined reference. Now under
  HAVE_MENU + a shader stack (COMPANION_HAVE_SHADERS); without one the
  accessors report no shader, which is the truth.
- ui/drivers/ui_qt_widgets.h declared ShaderPass / ShaderParamsDialog
  under HAVE_MENU while ui_qt_widgets.cpp defines them under HAVE_MENU +
  shader stack, so moc emitted metaobject code for 40 methods nobody
  defined. The declaration now uses the same test; all use sites in
  ui_qt.cpp were already gated.

Reproduced and re-checked at translation-unit level with the shader
defines removed (config.h and -D): before, nm showed the 40 dangling
ShaderParamsDialog references and menu_shader_get; after, none. The CI
job now passes --disable-glsl --disable-slang --disable-cg
--disable-glslang --disable-spirv_cross explicitly so it builds this
configuration regardless of what the runner has installed - it is the
one configuration no other job covers.

The companion test scripts (core, win32, cocoa) stub menu_shader_get()
and test the shader accessors, i.e. they emulate a build WITH a shader
stack; they now say so with -DHAVE_GLSL. companion_core_test plain +
asan OK; companion_win32_test OK under wine.

.github/workflows/Linux-qt-companion.yml

@@ -21,6 +21,12 @@ jobs:
     # companion's window geometry and dock layout must reach
     # retroarch.cfg when RetroArch quits with the companion window still
     # open, and a saved layout must restore and re-save identically.
+    #
+    # The shader stacks are disabled explicitly: with no OpenGL/Vulkan
+    # dev packages on the runner this is a Qt build with NO shader stack
+    # at all, and it links (the shader-preset editor and the companion
+    # core's shader accessors are compiled out). That is deliberate - it
+    # is the one configuration the other jobs never build.
     runs-on: ubuntu-latest
     steps:
       - name: Dependencies
@@ -55,7 +61,8 @@ jobs:
             --disable-roar --disable-al --disable-xvideo --disable-kms \
             --disable-egl --disable-dispmanx --disable-videocore \
             --disable-crtswitchres --disable-update_cores --disable-hid \
-            --disable-dbus
+            --disable-dbus --disable-glsl --disable-slang --disable-cg \
+            --disable-glslang --disable-spirv_cross
       - name: Build
         run: make -j$(getconf _NPROCESSORS_ONLN)
       - name: Companion persistence regression

tools/companion_cocoa_test.sh

@@ -55,7 +55,7 @@ EOF
 
 LC=libretro-common
 INC="-I$SHIM -I. -I$LC/include -Ideps -Igfx/include"
-DEFS="-DRARCH_INTERNAL -DLIBRETRO_STRL_CHECK_OVERLAP -DHAVE_MENU -DHAVE_CONFIGFILE -DHAVE_THREADS -DHAVE_COCOA -DTARGET_OS_OSX=1 -DHAVE_RPNG -DHAVE_RTGA -DHAVE_COMPANION_WIMP -DCOMPANION_TEST_NO_MAIN -DCOMPANION_CORE_TESTING"
+DEFS="-DRARCH_INTERNAL -DLIBRETRO_STRL_CHECK_OVERLAP -DHAVE_MENU -DHAVE_GLSL -DHAVE_CONFIGFILE -DHAVE_THREADS -DHAVE_COCOA -DTARGET_OS_OSX=1 -DHAVE_RPNG -DHAVE_RTGA -DHAVE_COMPANION_WIMP -DCOMPANION_TEST_NO_MAIN -DCOMPANION_CORE_TESTING"
 SAN=""
 case "${1:-}" in
    asan) SAN="-fsanitize=address -fno-omit-frame-pointer" ;;

tools/companion_core_test.sh

@@ -23,7 +23,9 @@ trap 'rm -rf "$OUT"' EXIT
 
 LC=libretro-common
 INC="-I. -I$LC/include -Ideps -Igfx/include"
-DEFS="-DRARCH_INTERNAL -DLIBRETRO_STRL_CHECK_OVERLAP -DHAVE_MENU -DHAVE_CONFIGFILE -DHAVE_THREADS -DHAVE_COMPANION_WIMP -DHAVE_RPNG -DHAVE_RTGA -DCOMPANION_CORE_TESTING"
+# HAVE_GLSL: the fixture stubs menu_shader_get(); the core only compiles
+# its shader accessors when some shader stack is present.
+DEFS="-DRARCH_INTERNAL -DLIBRETRO_STRL_CHECK_OVERLAP -DHAVE_MENU -DHAVE_CONFIGFILE -DHAVE_THREADS -DHAVE_COMPANION_WIMP -DHAVE_RPNG -DHAVE_RTGA -DHAVE_GLSL -DCOMPANION_CORE_TESTING"
 SRCS="ui/companion/companion_core.c \
       ui/companion/companion_thumbs.c \
       gfx/gfx_anim_preview.c \

tools/companion_win32_test.sh

@@ -22,7 +22,7 @@ trap 'rm -rf "$OUT"' EXIT
 
 LC=libretro-common
 INC="-I. -I$LC/include -Ideps -Igfx/include"
-DEFS="-DRARCH_INTERNAL -DLIBRETRO_STRL_CHECK_OVERLAP -DHAVE_MENU -DHAVE_CONFIGFILE -DHAVE_THREADS -DHAVE_RPNG -DHAVE_RTGA -DHAVE_COMPANION_WIMP -DCOMPANION_TEST_NO_MAIN -DCOMPANION_CORE_TESTING"
+DEFS="-DRARCH_INTERNAL -DLIBRETRO_STRL_CHECK_OVERLAP -DHAVE_MENU -DHAVE_GLSL -DHAVE_CONFIGFILE -DHAVE_THREADS -DHAVE_RPNG -DHAVE_RTGA -DHAVE_COMPANION_WIMP -DCOMPANION_TEST_NO_MAIN -DCOMPANION_CORE_TESTING"
 
 CSRCS="ui/companion/companion_core.c \
        ui/companion/companion_thumbs.c \

ui/companion/companion_core.c

@@ -641,13 +641,16 @@ void companion_core_option_reset_all(companion_core_t *core)
       companion_core_option_reset(core, i);
 }
 
-#ifdef HAVE_MENU
+/* menu_shader_get() is only compiled when a shader stack is; without
+ * one the companions simply have no shader parameters to show. */
+#if defined(HAVE_MENU) && (defined(HAVE_CG) || defined(HAVE_GLSL) || defined(HAVE_SLANG) || defined(HAVE_HLSL))
+#define COMPANION_HAVE_SHADERS 1
 #include "../../menu/menu_shader.h"
 #endif
 
 static struct video_shader *companion_core_shader(void)
 {
-#ifdef HAVE_MENU
+#ifdef COMPANION_HAVE_SHADERS
    return menu_shader_get();
 #else
    return NULL;

ui/drivers/ui_qt_widgets.h

@@ -744,8 +744,14 @@ protected:
  * and HAVE_CG/GLSL/SLANG/HLSL in the .cpp; gate the declarations to
  * match so moc does not emit metaobject code for a class that has
  * no defined methods. Forward declarations above keep external
- * pointer-typed members valid. */
-#ifdef HAVE_MENU
+ * pointer-typed members valid.
+ *
+ * The shader-preset editor also needs a shader stack: its definitions
+ * in ui_qt_widgets.cpp are under the same test, and so must this
+ * declaration be, or moc emits metaobject code that references methods
+ * no translation unit defines (a Qt build with no OpenGL/Vulkan dev
+ * packages - the CI Qt companion job - failed to link this way). */
+#if defined(HAVE_MENU) && (defined(HAVE_CG) || defined(HAVE_GLSL) || defined(HAVE_SLANG) || defined(HAVE_HLSL))
 
 class ShaderPass
 {
@@ -818,7 +824,7 @@ protected:
    void paintEvent(QPaintEvent *event);
 };
 
-#endif /* HAVE_MENU - shader-preset editor */
+#endif /* HAVE_MENU + shader stack - shader-preset editor */
 
 class ViewOptionsWidget : public QWidget
 {