feat: made plugin actions return Result

Errors on the engine-side are automatically handled and returned through
the CLI, while those on the browser-side are handled through a single
`panic!` that will go to the user's defined browser-side panic handler

Closes #234.

BREAKING CHANGE: all plugin actions must now return `Result<T, Box<dyn
std::error::Error>>` (return some arbitrary error and then use
`.into()`)
BREAKING CHANGE: all plugin actions that previously took
`Rc<perseus::errors::EngineError>` now take `Rc<perseus::errors::Error>`

examples/core/plugins/src/plugin.rs

@@ -16,16 +16,16 @@ pub fn get_test_plugin<G: perseus::Html>() -> Plugin<G, TestPluginData> {
                 .register_plugin("test-plugin", |_, _| {
                     let mut map = std::collections::HashMap::new();
                     map.insert("/Cargo.toml".to_string(), "Cargo.toml".to_string());
-                    map
+                    Ok(map)
                 });
             actions.settings_actions.add_templates.register_plugin(
                 "test-plugin",
                 |_, plugin_data| {
                     if let Some(plugin_data) = plugin_data.downcast_ref::<TestPluginData>() {
                         let about_page_greeting = plugin_data.about_page_greeting.to_string();
-                        vec![Template::new("about").template(move |cx| {
+                        Ok(vec![Template::new("about").template(move |cx| {
                             sycamore::view! { cx,  p { (about_page_greeting) } }
-                        })]
+                        })])
                     } else {
                         unreachable!()
                     }
@@ -38,6 +38,7 @@ pub fn get_test_plugin<G: perseus::Html>() -> Plugin<G, TestPluginData> {
                 let test = "[package]\name = \"test\"";
                 let parsed: toml::Value = toml::from_str(test).unwrap();
                 println!("{}", toml::to_string(&parsed).unwrap());
+                Ok(())
             });
             actions
         },

packages/perseus/src/client.rs

@@ -1,10 +1,12 @@
+use crate::errors::PluginError;
 use crate::{
     checkpoint,
     plugins::PluginAction,
     router::{perseus_router, PerseusRouterProps},
     template::TemplateNodeType,
 };
 use crate::{i18n::TranslationsManager, stores::MutableStore, PerseusAppBase};
+use fmterr::fmt_err;
 use std::collections::HashMap;
 use wasm_bindgen::JsValue;
 
@@ -22,7 +24,6 @@ pub fn run_client<M: MutableStore, T: TranslationsManager>(
     app: impl Fn() -> PerseusAppBase<TemplateNodeType, M, T>,
 ) -> Result<(), JsValue> {
     let mut app = app();
-    let plugins = app.get_plugins();
     let panic_handler = app.take_panic_handler();
 
     checkpoint("begin");
@@ -38,27 +39,44 @@ pub fn run_client<M: MutableStore, T: TranslationsManager>(
         }
     }));
 
+    let res = client_core(app);
+    if let Err(err) = res {
+        // This will go to the panic handler we defined above
+        // Unfortunately, at this stage, we really can't do anything else
+        panic!("plugin error: {}", fmt_err(&err));
+    }
+
+    Ok(())
+}
+
+/// This executes the actual underlying browser-side logic, including
+/// instantiating the user's app. This is broken out due to plugin fallibility.
+fn client_core<M: MutableStore, T: TranslationsManager>(
+    app: PerseusAppBase<TemplateNodeType, M, T>,
+) -> Result<(), PluginError> {
+    let plugins = app.get_plugins();
+
     plugins
         .functional_actions
         .client_actions
         .start
-        .run((), plugins.get_plugin_data());
+        .run((), plugins.get_plugin_data())?;
     checkpoint("initial_plugins_complete");
 
     // Get the root we'll be injecting the router into
     let root = web_sys::window()
         .unwrap()
         .document()
         .unwrap()
-        .query_selector(&format!("#{}", app.get_root()))
+        .query_selector(&format!("#{}", app.get_root()?))
         .unwrap()
         .unwrap();
 
     // Set up the properties we'll pass to the router
     let router_props = PerseusRouterProps {
-        locales: app.get_locales(),
+        locales: app.get_locales()?,
         error_pages: app.get_error_pages(),
-        templates: app.get_templates_map(),
+        templates: app.get_templates_map()?,
         render_cfg: get_render_cfg().expect("render configuration invalid or not injected"),
         pss_max_size: app.get_pss_max_size(),
     };

packages/perseus/src/engine/build.rs

@@ -1,9 +1,7 @@
 use crate::build::{build_app, BuildProps};
+use crate::errors::Error;
 use crate::{
-    errors::{EngineError, ServerError},
-    i18n::TranslationsManager,
-    plugins::PluginAction,
-    stores::MutableStore,
+    errors::ServerError, i18n::TranslationsManager, plugins::PluginAction, stores::MutableStore,
     PerseusAppBase, SsrNode,
 };
 use std::rc::Rc;
@@ -15,37 +13,43 @@ use std::rc::Rc;
 /// Note that this expects to be run in the root of the project.
 pub async fn build<M: MutableStore, T: TranslationsManager>(
     app: PerseusAppBase<SsrNode, M, T>,
-) -> Result<(), Rc<EngineError>> {
+) -> Result<(), Rc<Error>> {
     let plugins = app.get_plugins();
 
     plugins
         .functional_actions
         .build_actions
         .before_build
-        .run((), plugins.get_plugin_data());
+        .run((), plugins.get_plugin_data())
+        .map_err(|err| Rc::new(err.into()))?;
 
-    let immutable_store = app.get_immutable_store();
+    let immutable_store = app
+        .get_immutable_store()
+        .map_err(|err| Rc::new(err.into()))?;
     let mutable_store = app.get_mutable_store();
-    let locales = app.get_locales();
+    let locales = app.get_locales().map_err(|err| Rc::new(err.into()))?;
     // Generate the global state
     let gsc = app.get_global_state_creator();
     let global_state = match gsc.get_build_state().await {
         Ok(global_state) => global_state,
         Err(err) => {
-            let err: Rc<EngineError> = Rc::new(ServerError::GlobalStateError(err).into());
+            let err: Rc<Error> = Rc::new(ServerError::GlobalStateError(err).into());
             plugins
                 .functional_actions
                 .build_actions
                 .after_failed_global_state_creation
-                .run(err.clone(), plugins.get_plugin_data());
+                .run(err.clone(), plugins.get_plugin_data())
+                .map_err(|err| Rc::new(err.into()))?;
             return Err(err);
         }
     };
 
     // Build the site for all the common locales (done in parallel)
     // All these parameters can be modified by `PerseusApp` and plugins, so there's
     // no point in having a plugin opportunity here
-    let templates_map = app.get_atomic_templates_map();
+    let templates_map = app
+        .get_atomic_templates_map()
+        .map_err(|err| Rc::new(err.into()))?;
 
     // We have to get the translations manager last, because it consumes everything
     let translations_manager = app.get_translations_manager().await;
@@ -61,20 +65,22 @@ pub async fn build<M: MutableStore, T: TranslationsManager>(
     })
     .await;
     if let Err(err) = res {
-        let err: Rc<EngineError> = Rc::new(err.into());
+        let err: Rc<Error> = Rc::new(err.into());
         plugins
             .functional_actions
             .build_actions
             .after_failed_build
-            .run(err.clone(), plugins.get_plugin_data());
+            .run(err.clone(), plugins.get_plugin_data())
+            .map_err(|err| Rc::new(err.into()))?;
 
         Err(err)
     } else {
         plugins
             .functional_actions
             .build_actions
             .after_successful_build
-            .run((), plugins.get_plugin_data());
+            .run((), plugins.get_plugin_data())
+            .map_err(|err| Rc::new(err.into()))?;
 
         Ok(())
     }

packages/perseus/src/engine/dflt_engine.rs

@@ -109,7 +109,13 @@ where
         EngineOperation::Serve => {
             // To reduce friction for default servers and user-made servers, we
             // automatically do the boilerplate that all servers would have to do
-            let props = get_props(app());
+            let props = match get_props(app()) {
+                Ok(props) => props,
+                Err(err) => {
+                    eprintln!("{}", fmt_err(&err));
+                    return 1;
+                }
+            };
             // This returns a `(String, u16)` of the host and port for maximum compatibility
             let addr = get_host_and_port();
             // In production, give the user a heads up that something's actually happening
@@ -123,10 +129,12 @@ where
             serve_fn(props, addr).await;
             0
         }
-        EngineOperation::Tinker => {
-            // This is infallible (though plugins could panic)
-            super::engine_tinker(app());
-            0
-        }
+        EngineOperation::Tinker => match super::engine_tinker(app()) {
+            Ok(_) => 0,
+            Err(err) => {
+                eprintln!("{}", fmt_err(&err));
+                1
+            }
+        },
     }
 }