| name | downspout-build-test |
| description | Build, test, and verify downspout plugins and core targets. Use when Codex needs to configure CMake, build a plugin or test target, run CTest/core tests, choose narrow verification for a change, or avoid known downspout build-directory races. |
Downspout Build Test
Use this skill whenever validating downspout code changes.
Build-directory rule
On a fresh CMake build directory, do not start cmake --build until configure has fully completed. This repo can race cache generation and fail with Error: could not load cache if build starts too early.
Before building, check whether the target build directory has CMakeCache.txt:
find build -maxdepth 1 -name CMakeCache.txt -print
If no cache exists, configure first and wait for success:
cmake -S . -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_TESTING=ON
Fast plugin verification
For a plugin change, usually run:
cmake --build build --target downspout_<plugin_id>_core_tests
./build/plugins/<plugin>/downspout_<plugin_id>_core_tests
cmake --build build --target <bundle_target>
ctest --test-dir build -R downspout_<plugin_id>_core_tests --output-on-failure
Use the plugin-local CMakeLists.txt to confirm exact target names. Hyphenated plugin names often use underscores in C++/test/bundle names, for example p-mix has downspout_p_mix_core_tests and p_mix.vst3.
Verification scope
- Core-only logic: build and run the plugin core test executable.
- DPF wrapper or UI changes: also build the plugin target.
- Build/install/release script changes: run shell syntax checks and the affected script in the narrowest safe mode.
- Screenshot or Pages changes: use the screenshot/catalog workflow skill.
- Shared code changes: broaden tests to all impacted plugins.
VST3 validation
When a VST3 bundle is rejected by a host, run Steinberg's command-line
validator against the built or installed bundle. Compare with a known-working
Downspout bundle when the output might reflect a DPF-wide limitation.
The locally installed validator is currently:
/home/danny/tools/vst3sdk-build/bin/Release/validator /path/to/plugin.vst3
Treat a signal, non-zero exit status, sanitizer report, or failed test as a
failure even if earlier tests are marked Succeeded. Validator output can be
very large for DPF MIDI plugins, so capture it to a temporary log and search for
Failed, invalid, AddressSanitizer, and the final Result: line.
Read references/commands.md for target naming, useful commands, and validation heuristics.
