downspout-build-test

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.