Plugin API versioned

Without a declared plugin API version, every host release is a potential silent breaking change for the entire plugin ecosystem. Plugins have no way to declare compatibility, so the host cannot warn before loading an incompatible plugin, and plugin authors have no signal to know which host version their code targets. ISO 25010 maintainability.modifiability requires that the impact of changes be assessable before they are made; API versioning is the mechanism that makes that assessment possible at the plugin-host boundary.

Declare a PLUGIN_API_VERSION constant in the host and require plugins to specify their compatible version range in their manifest. Reject plugins at load time when the range is not satisfied.

// Host declares its API version:
export const PLUGIN_API_VERSION = '2.0.0';

// plugin.json:
{ "name": "my-plugin", "engines": { "host": "^2.0.0" } }

// Host checks on load:
if (!semver.satisfies(PLUGIN_API_VERSION, plugin.manifest.engines.host)) {
  throw new PluginIncompatibleError(
    plugin.name, plugin.manifest.engines.host, PLUGIN_API_VERSION
  );
}