Fix 5: Allow backward-compatibility and add plugin-template-v2

crates/ocs_plugin_api/src/lib.rs

@@ -41,7 +41,9 @@ pub mod shm;
 #[cfg(feature = "host")]
 pub mod runner;
 
-pub use manifest::{ApiVersion, PluginManifest, API_VERSION, API_VERSION_MIN_SUPPORTED};
+pub use manifest::{
+    host_accepts_plugin_version, ApiVersion, PluginManifest, API_VERSION, API_VERSION_MIN_SUPPORTED,
+};
 pub use ribbon::{CadModule, IconKind, ModuleEvent, RibbonGroup, RibbonItem, StyleKey, ToolDef};
 
 #[cfg(feature = "host")]

crates/ocs_plugin_api/src/manifest.rs

@@ -28,6 +28,13 @@ impl ApiVersion {
     }
 }
 
+/// True when a plugin built against `plugin_major` can be loaded by this host.
+/// The host supports majors from `API_VERSION_MIN_SUPPORTED` up to
+/// `API_VERSION`.
+pub fn host_accepts_plugin_version(plugin_major: u32) -> bool {
+    plugin_major >= API_VERSION_MIN_SUPPORTED && plugin_major <= API_VERSION
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/ocs_plugin_api/src/runner.rs

@@ -152,7 +152,7 @@ unsafe fn load_plugin(path: &Path) -> Result<Box<dyn BuiltinPlugin>, Box<dyn std
         .get(b"ocs_plugin_api_version")
         .map_err(|_| "missing ocs_plugin_api_version symbol")?;
     let v = version();
-    if v < crate::API_VERSION_MIN_SUPPORTED || v > crate::API_VERSION {
+    if !crate::host_accepts_plugin_version(v) {
         return Err(format!(
             "API version {v} is incompatible (host supports {}-{})",
             crate::API_VERSION_MIN_SUPPORTED,