dtourolleandClaude Opus 5
2d95807542
The Android bundling landed the weights under that platform's asset directory, which was the wrong home the moment a second packager wanted them. `makepkg -si` produced a desktop install with no model at all — the same "no face model is installed" the phone used to show, for the same reason: nothing put the files anywhere the app looks. So `models/face/` at the root is the one copy, and both packagers read it: assemble-apk.sh bundles it as APK assets, and the PKGBUILD installs it to /usr/share/darkroom/models. Both refuse an LFS pointer rather than shipping a 130-byte file that fails inside the graph loader on a user's machine. `face_models` now searches three places, most specific first: the account's own directory, the shared user directory, then $XDG_DATA_DIRS. So a packaged pair is found automatically and a pair the user placed by hand still outranks it — which is what keeps a deliberate choice of weights from being overridden by an upgrade. $XDG_DATA_DIRS rather than a hard-coded /usr/share: that is the variable a distribution, a prefix install or a Nix-style store already sets to say where its data went, and its documented default is exactly the two paths that would otherwise have been hard-coded. Empty on Android, which has no such directories — there the APK's copy is unpacked into the shared user directory instead, because an asset inside a package is not a path anything can read from. Verified: the APK still carries both models at assets/models/, the PKGBUILD parses and installs from the new path, 467 tests pass. Includes the pkgver 0.6.0 → 0.7.0 bump that was already sitting uncommitted in the working tree. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Android build environment
Reproducible container for cross-compiling DarkRoom to Android. CI and local builds use the same image, so a break appears in one place rather than two.
Use
# Cross-compile for a device ABI
./docker/android/build.sh cargo ndk -t arm64-v8a build --release
# All four ABIs
./docker/android/build.sh cargo ndk -t arm64-v8a -t armeabi-v7a -t x86_64 -t x86 build --release
# Type-check without linking
./docker/android/build.sh cargo check --target aarch64-linux-android
# Interactive shell
./docker/android/build.sh
# After editing the Dockerfile
./docker/android/build.sh --rebuild
Prefers podman, falls back to docker. First run builds the image, which takes several minutes;
after that it is cached.
In CI
.gitea/workflows/android-image.yml builds this image and pushes it to
gitea.tourolle.paris/dtourolle/darkroom-android, which the Android job then runs inside. It is
called on every push and finishes in seconds unless something here changed — the image is tagged
with the git tree hash of docker/android/, so a rebuild happens when and only when a file in this
directory does.
Nothing needs pushing by hand. Editing the Dockerfile is the trigger; latest follows
automatically. To force a rebuild without a content change, run the workflow from the Gitea UI with
force set to true.
The job runs on the host runner rather than in a container, because it needs the Docker daemon and the runner host's cached registry credentials.
Face models
package.sh bundles models/face/ into the APK, and the entry point unpacks it on first launch.
That directory is shared with the Arch package rather than owned by this platform. The models are in LFS, so a clone without git lfs pull has 130-byte
pointers there; the build detects that and stops rather than shipping them.
This exists because Android offers no other route to a model: the directory the app reads from is
inside app-private storage, run-as needs a debuggable build, and the app has no picker and no
fetch. docs/faces.md §2.2a is the decision and its limits — these files come back out before anything
is published.
Pinned versions
| Component | Version | Why this one |
|---|---|---|
| JDK | 17 | AGP's stable target. The host's JDK 25 breaks Gradle. |
| Compile SDK | API 36 | Required for Play distribution |
| Min API | 28 (Android 9) | Floor where Vulkan support is dependable (NFR-COMPAT-1) |
| Build tools | 36.0.0 | Matches compile SDK |
| NDK | 27.2.12479018 (r27c) | Current LTS |
| Rust | 1.92.0 | Slint 1.17 requires it; cargo-ndk 4.1.x needs ≥ 1.86 |
| cargo-ndk | 4.1.2 |
Bumping any of these is a reviewable change, not silent drift.
Compile SDK versus min API
These are different and both matter. ANDROID_API (36) is what the SDK compiles against — the
newest APIs available. MIN_API (28) is what native code links against, and determines the
oldest device that can run the result.
cargo-ndk defaults to API 21 if not told otherwise, which is far below what this app needs.
CARGO_NDK_PLATFORM and the per-target linker paths both pin it to MIN_API. Verify with:
file target/aarch64-linux-android/release/*.so
# → "... for Android 28, built by NDK r27c"
Caching
The cargo registry and target directory persist in ~/.cache/darkroom-android, so rebuilds do not
re-download the crate index. Clear with:
rm -rf ~/.cache/darkroom-android
The Android target dir is kept separate from the host's target/ — sharing one directory between
host and container builds causes constant rebuilds as they invalidate each other's fingerprints.
What is not here
No emulator, no adb device access. This image cross-compiles; it does not run or deploy. Device
testing (spikes S2 and S10, which need two GPU vendors) happens on real hardware — the emulator's
GPU behaviour is not representative of Adreno or Mali, which is precisely what those spikes exist
to test.