Support for FFI calls with `@Native external` functions through Native assets on MacOS and iOS. This enables bundling native code without any build-system boilerplate code.
For more info see:
* https://github.com/flutter/flutter/issues/129757
### Implementation details for MacOS and iOS.
Dylibs are bundled by (1) making them fat binaries if multiple architectures are targeted, (2) code signing these, and (3) copying them to the frameworks folder. These steps are done manual rather than via CocoaPods. CocoaPods would have done the same steps, but (a) needs the dylibs to be there before the `xcodebuild` invocation (we could trick it, by having a minimal dylib in the place and replace it during the build process, that works), and (b) can't deal with having no dylibs to be bundled (we'd have to bundle a dummy dylib or include some dummy C code in the build file).
The dylibs are build as a new target inside flutter assemble, as that is the moment we know what build-mode and architecture to target.
The mapping from asset id to dylib-path is passed in to every kernel compilation path. The interesting case is hot-restart where the initial kernel file is compiled by the "inner" flutter assemble, while after hot restart the "outer" flutter run compiled kernel file is pushed to the device. Both kernel files need to contain the mapping. The "inner" flutter assemble gets its mapping from the NativeAssets target which builds the native assets. The "outer" flutter run get its mapping from a dry-run invocation. Since this hot restart can be used for multiple target devices (`flutter run -d all`) it contains the mapping for all known targets.
### Example vs template
The PR includes a new template that uses the new native assets in a package and has an app importing that. Separate discussion in: https://github.com/flutter/flutter/issues/131209.
### Tests
This PR adds new tests to cover the various use cases.
* dev/devicelab/bin/tasks/native_assets_ios.dart
* Runs an example app with native assets in all build modes, doing hot reload and hot restart in debug mode.
* dev/devicelab/bin/tasks/native_assets_ios_simulator.dart
* Runs an example app with native assets, doing hot reload and hot restart.
* packages/flutter_tools/test/integration.shard/native_assets_test.dart
* Runs (incl hot reload/hot restart), builds, builds frameworks for iOS, MacOS and flutter-tester.
* packages/flutter_tools/test/general.shard/build_system/targets/native_assets_test.dart
* Unit tests the new Target in the backend.
* packages/flutter_tools/test/general.shard/ios/native_assets_test.dart
* packages/flutter_tools/test/general.shard/macos/native_assets_test.dart
* Unit tests the native assets being packaged on a iOS/MacOS build.
It also extends various existing tests:
* dev/devicelab/bin/tasks/module_test_ios.dart
* Exercises the add2app scenario.
* packages/flutter_tools/test/general.shard/features_test.dart
* Unit test the new feature flag.
* Add an integration test to plugin template example
Dart unit tests don't exercise host-side plugin code at all, so the
example tests in the plugin template currently have very little
meaningful coverage. This adds an integration test to the example app
when creating a plugin, so that there's an example of how to actually
test that a complete round-trip plugin call works.
This is done as a separate template that's currently only used by the
plugin template because I don't know what a good example for a
non-plugin case would be that isn't largely just a duplicate of the
widget tests. However, the integration test pre-includes conditionals
around the parts that are plugin-specific so that it can more easily be
expanded to other use cases later (e.g., in
https://github.com/flutter/flutter/issues/68818).
Part of https://github.com/flutter/flutter/issues/82458
* Add integration test to expected dependencies of a plugin app
* Test fixes
* Make an explicit test case
Previously developers had to edit their `Runner.rc` file to update their executable's version information. Now, version information will automatically be set from `flutter build`'s arguments or the `pubspec.yaml` file for new projects.
Addresses https://github.com/flutter/flutter/issues/73652
* Building shared C source code as part of the native build for platforms Android, iOS, Linux desktop, MacOS desktop, and Windows desktop.
* Sample code doing a synchronous FFI call.
* Sample code doing a long running synchronous FFI call on a helper isolate.
* Use of `package:ffigen` to generate the bindings.
* Revert "Add libgcrypt as an explicit dependancy on Linux"
This reverts commit bf65b3d03ccdc1dd21c09f34d600d72b0636a784.
* libblkid & liblzma not explicitly required either
This stops them attempting to own a D-Bus name, which may not be possible if the
app is sandboxed (e.g. in a Snap). It's also probably what most developers would
expect is the correct behaviour by default.
