Fix the livekit_uniffi build hook for universal builds and allow code_assets 2.x

.changeset/dart_hook_code_assets_2.md

@@ -0,0 +1,20 @@
+---
+livekit-uniffi: patch
+---
+
+# Allow code_assets 2.x in the Dart package and stop re-running its build hook
+
+The `livekit_uniffi` Dart package capped `code_assets` below 2.0.0, which has since
+shipped. Its only breaking change (equality on `OS` and `Architecture`) does not
+affect the hook, and the cap would make the package unresolvable next to any
+dependency that already requires 2.x. The constraint now allows it, and the hook
+was verified against `code_assets 2.0.0` / `hooks 2.2.0`.
+
+The hook also registered the downloaded library as a dependency. Dependencies are
+inputs, so the hooks runner saw a file modified during the build and re-ran the
+hook, and the download, once on every fresh build. The registration is removed.
+
+The hook also wrote every target's library to the same shared path. A universal
+macOS build runs the hook once per architecture and then merges the results with
+`lipo`, which failed because the second download had overwritten the first. Each
+target now gets its own subdirectory.

livekit-uniffi/support/dart/hook/build.dart.tera

@@ -71,14 +71,22 @@ Future<Uri> _resolveLibrary(
     return local.uri;
   }
 
-  // Download mode: fetch the prebuilt library for the target. The hooks-runner
-  // already caches hook results across builds, so there's no manual cache check.
+  // Download mode: fetch the prebuilt library for the target. The hooks runner
+  // caches hook results across builds, so there is no manual cache check. The
+  // downloaded file is an output, not an input, so it is deliberately not
+  // registered as a dependency: doing so made the runner see a file modified
+  // during the build and rerun the hook (and the download) once per fresh build.
+  //
+  // The shared directory is one per package, not per target, and a universal
+  // macOS build runs this hook once per architecture before lipo merges the
+  // results. Keep each target in its own subdirectory, or the second download
+  // overwrites the first and lipo is handed the same architecture twice.
+  final triple = _targetTriple(os, arch, iosSdk);
   final outDir = Directory.fromUri(
-    input.outputDirectoryShared.resolve('$_cdylibName/'),
+    input.outputDirectoryShared.resolve('$_cdylibName/$triple/'),
   );
   final libFile = File.fromUri(outDir.uri.resolve(libName));
 
-  final triple = _targetTriple(os, arch, iosSdk);
   // Asset naming matches the existing node downloader convention so one set of
   // release assets serves both: `<base>/v<version>/build-<triple>.zip`.
   final zipUrl = Uri.parse('$_downloadBase/v$_version/build-$triple.zip');
@@ -89,7 +97,7 @@ Future<Uri> _resolveLibrary(
   for (final entry in ZipDecoder().decodeBytes(bytes)) {
     if (!entry.isFile) continue;
     // Guard against zip-slip: `resolve` normalizes `../` and absolute paths, so
-    // an entry that lands outside `base` is a malicious name — reject it. The
+    // an entry that lands outside `base` is a malicious name, so reject it. The
     // SHA-256 check proves integrity against tampering in transit, not that a
     // compromised host can't serve a matching-checksum malicious archive.
     final entryUri = base.resolve(entry.name);
@@ -104,7 +112,6 @@ Future<Uri> _resolveLibrary(
   if (!await libFile.exists()) {
     throw Exception('$libName not found in $zipUrl');
   }
-  output.dependencies.add(libFile.uri);
   return libFile.uri;
 }
 

livekit-uniffi/support/dart/pubspec.yaml.tera

@@ -18,12 +18,16 @@ environment:
 dependencies:
   ffi: ^2.1.0
   # Native Assets build-hook support. pub.dev requires bounded constraints
-  # (`any` fails publish validation), but these must stay wide: the resolvable
-  # version is coupled to the consumer's Dart SDK via a shared `meta` pin
-  # (Flutter 3.44 back-solves to code_assets 1.0.0 / hooks 1.0.2, while a bare
-  # Dart 3.12 resolves 1.2.1 / 2.1.0). Carets here break `flutter pub get`
-  # for consumers on older stable channels.
-  code_assets: ">=1.0.0 <2.0.0"
+  # (`any` fails publish validation), but these must stay wide. The resolvable
+  # version is coupled to the consumer's Dart SDK: older hooks releases pin
+  # `meta`, which Flutter's flutter_test pins exactly, so Flutter 3.44
+  # back-solves to code_assets 1.0.0 / hooks 1.0.2 while a bare Dart 3.12
+  # resolves newer ones. Carets here break `flutter pub get` for consumers on
+  # older stable channels, and a tight upper bound makes this package
+  # unresolvable next to any package that already requires the next major.
+  # The hook uses only the stable core of both APIs (target config, CodeAsset,
+  # DynamicLoadingBundled), which is unchanged across these majors.
+  code_assets: ">=1.0.0 <3.0.0"
   hooks: ">=1.0.2 <3.0.0"
   # Used by hook/build.dart to download and verify prebuilt libraries.
   archive: ^4.0.0