Commit 9cc67a5

Real-time networked music jamming app. Qt/C++ qmake project. Client and server share one codebase; entry point: `src/main.cpp`. Configure `CONFIG` flags in `Jamulus.pro`.

**Make the smallest possible change. One logical change per PR. Never mix refactoring with fixes/features.**

Priority order: Stability > Low latency / real-time safety > Backwards compatibility > Maintainability > New features. This order resolves conflicts only — new features are welcome.

Linux: `qmake && make` (use `qmake-qt5` on Fedora). Headless server: `qmake "CONFIG+=headless serveronly" && make`. First run: `git submodule update --init` (oboe for Android). Run `make distclean` before re-running `qmake` with different `CONFIG` flags. Full per-platform table: `COMPILING.md`.

macOS: `qmake QMAKE_APPLE_DEVICE_ARCHS=arm64 QT_ARCH=arm64 -spec macx-xcode Jamulus.pro`

(Use `x86_64` on Intel Macs; `macx-clang` if using `make`). Then `xcodebuild build`,

and `macdeployqt ./{Debug,Release}/Jamulus.app`.

**Testing:** run headless server (args `-s -n`), connect a client to `localhost`, exercise the change; use the JSON-RPC API (`docs/JSON-RPC.md`) where possible. State what you tested in the PR with evidence. GitHub Actions builds multiple platforms — on failure read the failing step's log.

**`Never Do` rules are absolute**

- Block/slow real-time paths: audio callbacks (`src/sound/`), sockets (`src/socket.cpp`), server mixing timer (`src/server.cpp`). No allocation, file I/O, or excessive logging there; preallocate buffers, keep lock-free — stalls = audible dropouts.

- Trust values from remote clients — validate size/bounds on all network input (malformed input crashes).

- Edit generated files (`moc_*.cpp`, `ui_*.h`, `qrc_*.cpp`, `*.qm`) — regenerate; don't edit/reformat third-party code in `libs/`.

- Edit `ChangeLog` directly — use a `CHANGELOG:` line in the PR.

- Attach test evidence (logs/output) to the PR — never just assert something works.

- Say so if you did not run or verify something.

- Architecture changes (networking/protocol, threading, build system) — open an issue to discuss (see `CONTRIBUTING.md`).

- Minimum Qt: **5.12.2**. Qt 6 recommended (iOS: Qt 5.15+ required, Qt 6 iOS buggy). Guard newer APIs with `#if QT_VERSION >= QT_VERSION_CHECK(...)`.

- C++11 (C++17 on Android for Oboe).

- Preserve platform support.

- Desktop: Windows 10+, macOS 10.10+, Ubuntu 20.04+/Debian 11+.

- **CI uses clang-format** (version in `.github/workflows/coding-style-check.yml`).

- Run `make clang_format` before committing (works only after qmake).

- CI runs **shellcheck + shfmt** on `.sh` files; **pylint** (config: `.pylintrc`) on `.py` files in `tools/`.

- New contributions: AGPL 3.0+ license header. Pre-3.12.1dev code: GPL 3.0+ (see `CONTRIBUTING.md`).

- Use `tr ( "Hello %1" ).arg ( name )` for user-facing strings — never string concatenation.

- Changing RPC methods (e.g. `src/clientrpc.cpp` / `src/serverrpc.cpp`) requires regenerating `docs/JSON-RPC.md` with `tools/generate_json_rpc_docs.py` (CI fails otherwise).

- Requires `--jsonrpcport` + `--jsonrpcsecretfile` at runtime. Binds to localhost by default. Secret requires ≥16 characters.

- One logical change per PR — no unrelated cleanup or reformatting of untouched code. Discuss features in an issue before implementing. See `CONTRIBUTING.md`.

- Branch names starting with `autobuild` trigger CI builds on your fork.

- Follow `.github/pull_request_template.md`. Include `CHANGELOG:` line. Add `AUTOBUILD: Please build all targets` for skipped targets (iOS, Windows JACK, Linux armhf/arm64) if touched; see `.github/workflows/autobuild.yml`.

- Builds? Tested? Smallest change possible? Self reviewed against "Priority order" above?

- Disclose AI-generated text at the end of Comments/PRs. (e.g: `> Used AI: <model>, <harness>`) — never in code comments.

- `CONTRIBUTING.md` — process, style, licensing

- `COMPILING.md` — full build per platform, CONFIG flags table

- `docs/JAMULUS_PROTOCOL.md` — network protocol, packet IDs, ack rules

- `SECURITY.md` — security reporting