feat(null): add backend.manifest.zon — manifest-splice codegen (#386 step 2)

.github/workflows/ci.yml

@@ -75,25 +75,6 @@ jobs:
       - name: sokol backend unit tests + audio.zig compile-check
         run: cd backends/sokol && zig build test
 
-      - name: wgpu backend WAV parser tests
-        # Re-enabled: wgpu_native_zig + zglfw are now on 0.16-compatible
-        # pins, and `zig build test` builds only the pure WAV parser
-        # (host target, no native deps), so it stays cheap on both OSes.
-        run: cd backends/wgpu && zig build test
-
-      # Build the standalone wgpu backend demo on macOS. This is the
-      # regression lock for the Apple render path: the example used to
-      # link a nonexistent Dawn `zdawn` artifact (panicked "unable to
-      # find artifact 'zdawn'"), and surface creation was Win32-only.
-      # Building here exercises example/build.zig (drops Dawn, links the
-      # Metal/QuartzCore/Foundation frameworks wgpu-native needs) AND
-      # compiles window.zig's CAMetalLayer surface path for real on an
-      # Apple target. macOS-only: the frameworks + Cocoa surface only
-      # exist here, and it's the platform the break shipped on.
-      - name: wgpu backend demo build (macOS)
-        if: runner.os == 'macOS'
-        run: cd backends/wgpu/example && zig build
-
       # Linux-only: raylib-zig transitively pulls hexops/xcode-frameworks
       # via `git+https://`, which Zig's git fetcher can't resolve on the
       # macos-latest runner ("unable to discover remote git server
@@ -249,39 +230,6 @@ jobs:
           cd .labelle/raylib_desktop
           zig build
 
-      # wgpu desktop example — build-only, same recipe. This backend
-      # previously had NO example build in CI at all, which let a codegen
-      # bug ship (its lifecycle template lacked the {{module_vars}} slot,
-      # so generated mains referenced undeclared `_preview_*` helpers and
-      # failed sema — caught only when a real project switched backends).
-      # bgfx isn't built here (or anywhere in this repo) — it's extracted to
-      # labelle-bgfx, which builds + tests it (incl. the android .so) in its
-      # own CI. This job covers the bundled backends' example codegen.
-      - name: Generate + build the wgpu example
-        env:
-          LABELLE_ASSEMBLER: ${{ github.workspace }}/labelle-assembler/zig-out/bin/labelle-assembler
-        run: |
-          cd labelle-assembler/examples/wgpu
-          $GITHUB_WORKSPACE/labelle-cli/zig-out/bin/labelle generate
-
-          # Lock the `link_wgpu` template: wgpu-native's static lib pulls
-          # Apple system frameworks, so the generated build MUST link
-          # Foundation/QuartzCore/Metal on macOS/iOS or those targets fail
-          # to link with undefined Metal symbols. This runner is Linux (so
-          # `zig build` below can't link-test the frameworks), but the
-          # generated build.zig is platform-agnostic — assert the framework
-          # links are present so a template regression is caught here even
-          # without a macOS runner. The standalone demo build in the
-          # build-and-test macOS job link-tests them for real.
-          for fw in Foundation QuartzCore Metal; do
-            grep -qF "linkFramework(\"$fw\"" .labelle/wgpu_desktop/build.zig \
-              || { echo "E: generated wgpu build.zig is missing linkFramework(\"$fw\") — link_wgpu template regression"; exit 1; }
-          done
-          echo "PASS: generated wgpu build.zig links Foundation/QuartzCore/Metal"
-
-          cd .labelle/wgpu_desktop
-          zig build
-
       # External (out-of-tree) backend wiring, backend-AGNOSTIC. Proves the
       # opt-in `.backend_package` path end-to-end: `install` FETCHES the backend
       # package from GitHub into the cache, then `generate` stages it + codegens

backends/null/backend.manifest.zon

@@ -0,0 +1,25 @@
+.{
+    // null backend manifest — pluggable-backends epic (labelle-assembler#386).
+    //
+    // Presence of this file opts the null DESKTOP build into the manifest-splice
+    // codegen path (manifest_splice.zig) instead of the enum `switch (cfg.backend)`
+    // sections in src/templates/build_zig.txt. Spliced output is byte-identical to
+    // the enum path (verified against a generated baseline) — the step that lets
+    // null move out-of-tree (its build sections travel WITH the package).
+    //
+    // Loop-style (the generated headless main drives a fixed-frame tick loop). No
+    // params: pure-Zig, zero native deps, and the LINK fragment is EMPTY — null has
+    // no artifact to link (the enum path's `.null => {}` emitted nothing).
+    .dir_name = "null",
+    .dep_name = "labelle_null",
+    .loop_style = .loop,
+    .main_loop_template = "templates/headless.txt",
+    .build_fragments = .{
+        .backend_dep = "build_fragments/backend_dep.txt",
+        .link = "build_fragments/link.txt",
+    },
+    .params = .{
+        .backend_dep = .{},
+        .link = .{},
+    },
+}

backends/wgpu/build_fragments/backend_dep.txt → backends/null/build_fragments/backend_dep.txt

@@ -1,7 +1,8 @@
-    const backend_dep = b.dependency("labelle_wgpu", .{ .target = target, .optimize = optimize });
+    // Null backend — pure Zig, no native artifact. Every backend module is
+    // a no-op stub; the generated main() drives a fixed-frame tick loop.
+    const backend_dep = b.dependency("labelle_null", .{ .target = target, .optimize = optimize });
     const backend_gfx = backend_dep.module("gfx");
     const backend_input = backend_dep.module("input");
     const backend_audio = backend_dep.module("audio");
     const backend_window = backend_dep.module("window");
-    const glfw_artifact = backend_dep.artifact("glfw");