[IMP] *: use a custom error class for all errors thrown by owl

This commit makes all errors thrown in owl use a custom error class. The
main point of this is to always wrap user-code errors that happen during
the owl lifecycle so that they can be treated uniformly in onError by
checking the cause property, and also allows user code to differenciate
owl errors from non-owl errors reliably at runtime.

src/runtime/template_helpers.ts

@@ -4,6 +4,7 @@ import { html } from "./blockdom/index";
 import { isOptional, validateSchema } from "./validation";
 import type { ComponentConstructor } from "./component";
 import { markRaw } from "./reactivity";
+import { OwlError } from "./error_handling";
 
 const ObjectCreate = Object.create;
 /**
@@ -70,7 +71,7 @@ function prepareList(collection: any): [any[], any[], number, any[]] {
     values = Object.keys(collection);
     keys = Object.values(collection);
   } else {
-    throw new Error("Invalid loop expression");
+    throw new OwlError("Invalid loop expression");
   }
   const n = values.length;
   return [keys, values, n, new Array(n)];
@@ -191,7 +192,7 @@ function multiRefSetter(refs: RefMap, name: string): RefSetter {
     if (el) {
       count++;
       if (count > 1) {
-        throw new Error("Cannot have 2 elements with same ref name at the same time");
+        throw new OwlError("Cannot have 2 elements with same ref name at the same time");
       }
     }
     if (count === 0 || el) {
@@ -233,7 +234,7 @@ export function validateProps<P>(name: string | ComponentConstructor<P>, props:
         : name in schema && !("*" in schema) && !isOptional(schema[name]);
     for (let p in defaultProps) {
       if (isMandatory(p)) {
-        throw new Error(
+        throw new OwlError(
           `A default value cannot be defined for a mandatory prop (name: '${p}', component: ${ComponentClass.name})`
         );
       }
@@ -242,7 +243,9 @@ export function validateProps<P>(name: string | ComponentConstructor<P>, props:
 
   const errors = validateSchema(props, schema);
   if (errors.length) {
-    throw new Error(`Invalid props for component '${ComponentClass.name}': ` + errors.join(", "));
+    throw new OwlError(
+      `Invalid props for component '${ComponentClass.name}': ` + errors.join(", ")
+    );
   }
 }
 
@@ -264,4 +267,5 @@ export const helpers = {
   bind,
   createCatcher,
   markRaw,
+  OwlError,
 };