fix(runtime): don't render when crashing (#2746)

src/client/client-log.ts

@@ -1,7 +1,8 @@
 import type * as d from '../declarations';
 import { BUILD } from '@app-data';
 
-let customError: d.ErrorHandler ;
+let customError: d.ErrorHandler;
+
 export const consoleError: d.ErrorHandler = (e: any, el?: any) => (customError || console.error)(e, el);
 
 export const STENCIL_DEV_MODE = BUILD.isTesting

src/hydrate/platform/index.ts

@@ -1,6 +1,8 @@
 import type * as d from '../../declarations';
 import { addHostEventListeners } from '@runtime';
 
+let customError: d.ErrorHandler;
+
 export const cmpModules = new Map<string, { [exportName: string]: d.ComponentConstructor }>();
 
 const getModule = (tagName: string): d.ComponentConstructor => {
@@ -71,12 +73,14 @@ export const writeTask = (cb: Function) => {
 const resolved = /*@__PURE__*/ Promise.resolve();
 export const nextTick = /*@__PURE__*/ (cb: () => void) => resolved.then(cb);
 
-export const consoleError = (e: any) => {
+const defaultConsoleError = (e: any) => {
   if (e != null) {
     console.error(e.stack || e.message || e);
   }
 };
 
+export const consoleError: d.ErrorHandler = (e: any, el?: any) => (customError || defaultConsoleError)(e, el);
+
 export const consoleDevError = (..._: any[]) => {
   /* noop for hydrate */
 };
@@ -89,6 +93,8 @@ export const consoleDevInfo = (..._: any[]) => {
   /* noop for hydrate */
 };
 
+export const setErrorHandler = (handler: d.ErrorHandler) => customError = handler;
+
 /*hydrate context start*/ export const Context = {}; /*hydrate context end*/
 
 export const plt: d.PlatformRuntime = {

src/runtime/test/render-vdom.spec.tsx

@@ -1,4 +1,4 @@
-import { Component, Element, Host, Prop, State, forceUpdate, getRenderingRef, h } from '@stencil/core';
+import { Component, Element, setErrorHandler, Host, Prop, State, forceUpdate, getRenderingRef, h } from '@stencil/core';
 import { newSpecPage } from '@stencil/core/testing';
 
 describe('render-vdom', () => {
@@ -465,6 +465,42 @@ describe('render-vdom', () => {
     `);
   });
 
+  it('render crash should not remove the content', async () => {
+    let didError = false;
+    setErrorHandler((err) => {
+      didError = true;
+    });
+    @Component({ tag: 'cmp-a' })
+    class CmpA {
+      @Prop() crash = false;
+      render() {
+        if (this.crash) {
+          throw new Error('YOLO');
+        }
+        return <div>Hello</div>;
+      }
+    }
+
+    const { root, waitForChanges } = await newSpecPage({
+      components: [CmpA],
+
+      html: `<cmp-a></cmp-a>`,
+    });
+
+    expect(root).toEqualHtml(`
+      <cmp-a><div>Hello</div></cmp-a>
+    `);
+
+    expect(didError).toBe(false);
+    root.crash = true;
+    await waitForChanges();
+
+    expect(root).toEqualHtml(`
+      <cmp-a><div>Hello</div></cmp-a>
+    `);
+    expect(didError).toBe(true);
+  });
+
   it('Hello VDOM, html option', async () => {
     @Component({ tag: 'cmp-a' })
     class CmpA {

src/runtime/update-component.ts

@@ -81,19 +81,10 @@ const updateComponent = async (hostRef: d.HostRef, instance: any, isInitialLoad:
     hostRef.$flags$ |= HOST_FLAGS.devOnRender;
   }
 
-  if (BUILD.hasRenderFn || BUILD.reflect) {
-    if (BUILD.vdomRender || BUILD.reflect) {
-      // looks like we've got child nodes to render into this host element
-      // or we need to update the css class/attrs on the host element
-      // DOM WRITE!
-      if (BUILD.hydrateServerSide) {
-        renderVdom(hostRef, await callRender(hostRef, instance));
-      } else {
-        renderVdom(hostRef, callRender(hostRef, instance));
-      }
-    } else {
-      elm.textContent = callRender(hostRef, instance);
-    }
+  if (BUILD.hydrateServerSide) {
+    await callRender(hostRef, instance, elm);
+  } else {
+    callRender(hostRef, instance, elm);
   }
   if (BUILD.cssVarShim && plt.$cssShim$) {
     plt.$cssShim$.updateHost(elm);
@@ -149,7 +140,7 @@ const updateComponent = async (hostRef: d.HostRef, instance: any, isInitialLoad:
 
 let renderingRef: any = null;
 
-const callRender = (hostRef: d.HostRef, instance: any) => {
+const callRender = (hostRef: d.HostRef, instance: any, elm: HTMLElement) => {
   // in order for bundlers to correctly treeshake the BUILD object
   // we need to ensure BUILD is not deoptimized within a try/catch
   // https://rollupjs.org/guide/en/#treeshake tryCatchDeoptimization
@@ -169,11 +160,25 @@ const callRender = (hostRef: d.HostRef, instance: any) => {
     if (updatable || lazyLoad) {
       hostRef.$flags$ |= HOST_FLAGS.hasRendered;
     }
+    if (BUILD.hasRenderFn || BUILD.reflect) {
+      if (BUILD.vdomRender || BUILD.reflect) {
+        // looks like we've got child nodes to render into this host element
+        // or we need to update the css class/attrs on the host element
+        // DOM WRITE!
+        if (BUILD.hydrateServerSide) {
+          return Promise.resolve(instance).then(value => renderVdom(hostRef, value))
+        } else {
+          renderVdom(hostRef, instance);
+        }
+      } else {
+        elm.textContent = instance;
+      }
+    }
   } catch (e) {
     consoleError(e, hostRef.$hostElement$);
   }
   renderingRef = null;
-  return instance;
+  return null;
 };
 
 export const getRenderingRef = () => renderingRef;

src/testing/jest/jest-setup-test-framework.ts

@@ -5,7 +5,7 @@ import { setupGlobal, teardownGlobal } from '@stencil/core/mock-doc';
 import { setupMockFetch } from '../mock-fetch';
 import { HtmlSerializer } from './jest-serializer';
 import { resetBuildConditionals } from '../reset-build-conditionals';
-import { resetPlatform, stopAutoApplyChanges, modeResolutionChain } from '@stencil/core/internal/testing';
+import { resetPlatform, stopAutoApplyChanges, modeResolutionChain, setErrorHandler } from '@stencil/core/internal/testing';
 
 declare const global: d.JestEnvironmentGlobal;
 
@@ -22,6 +22,7 @@ export function jestSetupTestFramework() {
   beforeEach(() => {
     // reset the platform for this new test
     resetPlatform();
+    setErrorHandler(undefined);
     resetBuildConditionals(BUILD);
     modeResolutionChain.length = 0;
   });

src/testing/platform/index.ts

@@ -1,6 +1,6 @@
 export { Build } from './testing-build';
 export { Env } from '@app-data';
-export { consoleDevError, consoleDevInfo, consoleDevWarn, consoleError } from './testing-log';
+export { consoleDevError, consoleDevInfo, consoleDevWarn, consoleError, setErrorHandler } from './testing-log';
 export {
   Context,
   isMemberInElement,

src/testing/platform/testing-log.ts

@@ -1,9 +1,15 @@
+import type * as d from '../../declarations';
 import { caughtErrors } from './testing-constants';
 
-export const consoleError = (e: any) => {
+let customError: d.ErrorHandler;
+
+const defaultConsoleError = (e: any) => {
+  console.log('here', customError);
   caughtErrors.push(e);
 };
 
+export const consoleError: d.ErrorHandler = (e: any, el?: any) => (customError || defaultConsoleError)(e, el);
+
 export const consoleDevError = (...e: any[]) => {
   caughtErrors.push(new Error(e.join(', ')));
 };
@@ -15,3 +21,5 @@ export const consoleDevWarn = (..._: any[]) => {
 export const consoleDevInfo = (..._: any[]) => {
   /* noop for testing */
 };
+
+export const setErrorHandler = (handler: d.ErrorHandler) => customError = handler;

src/testing/platform/testing-platform.ts

@@ -1,5 +1,6 @@
 import type * as d from '@stencil/core/internal';
 import { cstrs, hostRefs, moduleLoaded, styles } from './testing-constants';
+import { setErrorHandler } from './testing-log';
 import { flushAll, resetTaskQueue } from './testing-task-queue';
 import { win } from './testing-window';