[IMP] component: improve errors when thrown from lifecycle hooks

Previously, a crash in a lifecycle hook for any reason would throw an
error whose stack trace started from the scheduler and contained only
the place where the hook was called by owl, but not the place where the
hook was registered by the user. This proved very difficult for users to
debug as they cannot really tell which component registered that hook.

This commit alleviates the issue by creating a new Error when the hook
is originally called, and wrapping the registered callback in a try
catch, throwing an error with the correct stack trace instead of the
error in the hook, and setting the error in the hook as the cause of
this synthetic error.

src/component/lifecycle_hooks.ts

@@ -1,62 +1,97 @@
 import { getCurrent } from "./component_node";
 import { nodeErrorHandlers } from "./error_handling";
 
+function wrapError(fn: (...args: any[]) => any, hookName: string) {
+  const error = new Error(`The following error occurred in ${hookName}: `) as Error & {
+    cause: any;
+  };
+  return (...args: any[]) => {
+    try {
+      const result = fn(...args);
+      if (result instanceof Promise) {
+        return result.catch((cause) => {
+          error.cause = cause;
+          if (cause instanceof Error) {
+            error.message += `"${cause.message}"`;
+          }
+          throw error;
+        });
+      }
+      return result;
+    } catch (cause) {
+      if (cause instanceof Error) {
+        error.message += `"${cause.message}"`;
+      }
+      throw error;
+    }
+  };
+}
+
 // -----------------------------------------------------------------------------
 //  hooks
 // -----------------------------------------------------------------------------
 
 export function onWillStart(fn: () => Promise<void> | void | any) {
   const node = getCurrent();
-  node.willStart.push(fn.bind(node.component));
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.willStart.push(decorate(fn.bind(node.component), "onWillStart"));
 }
 
 export function onWillUpdateProps(fn: (nextProps: any) => Promise<void> | void | any) {
   const node = getCurrent();
-  node.willUpdateProps.push(fn.bind(node.component));
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.willUpdateProps.push(decorate(fn.bind(node.component), "onWillUpdateProps"));
 }
 
 export function onMounted(fn: () => void | any) {
   const node = getCurrent();
-  node.mounted.push(fn.bind(node.component));
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.mounted.push(decorate(fn.bind(node.component), "onMounted"));
 }
 
 export function onWillPatch(fn: () => Promise<void> | any | void) {
   const node = getCurrent();
-  node.willPatch.unshift(fn.bind(node.component));
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.willPatch.unshift(decorate(fn.bind(node.component), "onWillPatch"));
 }
 
 export function onPatched(fn: () => void | any) {
   const node = getCurrent();
-  node.patched.push(fn.bind(node.component));
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.patched.push(decorate(fn.bind(node.component), "onPatched"));
 }
 
 export function onWillUnmount(fn: () => Promise<void> | void | any) {
   const node = getCurrent();
-  node.willUnmount.unshift(fn.bind(node.component));
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.willUnmount.unshift(decorate(fn.bind(node.component), "onWillUnmount"));
 }
 
 export function onWillDestroy(fn: () => Promise<void> | void | any) {
   const node = getCurrent();
-  node.willDestroy.push(fn.bind(node.component));
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.willDestroy.push(decorate(fn.bind(node.component), "onWillDestroy"));
 }
 
 export function onWillRender(fn: () => void | any) {
   const node = getCurrent();
   const renderFn = node.renderFn;
-  node.renderFn = () => {
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.renderFn = decorate(() => {
     fn.call(node.component);
     return renderFn();
-  };
+  }, "onWillRender");
 }
 
 export function onRendered(fn: () => void | any) {
   const node = getCurrent();
   const renderFn = node.renderFn;
-  node.renderFn = () => {
+  const decorate = node.app.dev ? wrapError : (fn: any) => fn;
+  node.renderFn = decorate(() => {
     const result = renderFn();
     fn.call(node.component);
     return result;
-  };
+  }, "onRendered");
 }
 
 type OnErrorCallback = (error: any) => void | any;