feat[devtools]: symbolicate source for inspected element (facebook#28471)

Stacked on facebook#28351, please review
only the last commit.

Top-level description of the approach:
1. Once user selects an element from the tree, frontend asks backend to
return the inspected element, this is where we simulate an error
happening in `render` function of the component and then we parse the
error stack. As an improvement, we should probably migrate from custom
implementation of error stack parser to `error-stack-parser` from npm.
2. When frontend receives the inspected element and this object is being
propagated, we create a Promise for symbolicated source, which is then
passed down to all components, which are using `source`.
3. These components use `use` hook for this promise and are wrapped in
Suspense.

Caching:
1. For browser extension, we cache Promises based on requested resource
+ key + column, also added use of
`chrome.devtools.inspectedWindow.getResource` API.
2. For standalone case (RN), we cache based on requested resource url,
we cache the content of it.

Author: hoxyq

.eslintrc.js

@@ -455,6 +455,13 @@ module.exports = {
         __IS_CHROME__: 'readonly',
         __IS_FIREFOX__: 'readonly',
         __IS_EDGE__: 'readonly',
+        __IS_INTERNAL_VERSION__: 'readonly',
+      },
+    },
+    {
+      files: ['packages/react-devtools-shared/**/*.js'],
+      globals: {
+        __IS_INTERNAL_VERSION__: 'readonly',
       },
     },
   ],

packages/react-debug-tools/package.json

@@ -28,6 +28,6 @@
     "react": "^17.0.0"
   },
   "dependencies": {
-    "error-stack-parser": "^2.0.2"
+    "error-stack-parser": "^2.1.4"
   }
 }

packages/react-devtools-core/src/standalone.js

@@ -33,7 +33,7 @@ import {
 import {localStorageSetItem} from 'react-devtools-shared/src/storage';
 
 import type {FrontendBridge} from 'react-devtools-shared/src/bridge';
-import type {InspectedElement} from 'react-devtools-shared/src/frontend/types';
+import type {Source} from 'react-devtools-shared/src/shared/types';
 
 installHook(window);
 
@@ -127,36 +127,55 @@ function reload() {
         store: ((store: any): Store),
         warnIfLegacyBackendDetected: true,
         viewElementSourceFunction,
+        fetchFileWithCaching,
       }),
     );
   }, 100);
 }
 
+const resourceCache: Map<string, string> = new Map();
+
+// As a potential improvement, this should be done from the backend of RDT.
+// Browser extension is doing this via exchanging messages
+// between devtools_page and dedicated content script for it, see `fetchFileWithCaching.js`.
+async function fetchFileWithCaching(url: string) {
+  if (resourceCache.has(url)) {
+    return Promise.resolve(resourceCache.get(url));
+  }
+
+  return fetch(url)
+    .then(data => data.text())
+    .then(content => {
+      resourceCache.set(url, content);
+
+      return content;
+    });
+}
+
 function canViewElementSourceFunction(
-  inspectedElement: InspectedElement,
+  _source: Source,
+  symbolicatedSource: Source | null,
 ): boolean {
-  if (
-    inspectedElement.canViewSource === false ||
-    inspectedElement.source === null
-  ) {
+  if (symbolicatedSource == null) {
     return false;
   }
 
-  const {source} = inspectedElement;
-
-  return doesFilePathExist(source.sourceURL, projectRoots);
+  return doesFilePathExist(symbolicatedSource.sourceURL, projectRoots);
 }
 
 function viewElementSourceFunction(
-  id: number,
-  inspectedElement: InspectedElement,
+  _source: Source,
+  symbolicatedSource: Source | null,
 ): void {
-  const {source} = inspectedElement;
-  if (source !== null) {
-    launchEditor(source.sourceURL, source.line, projectRoots);
-  } else {
-    log.error('Cannot inspect element', id);
+  if (symbolicatedSource == null) {
+    return;
   }
+
+  launchEditor(
+    symbolicatedSource.sourceURL,
+    symbolicatedSource.line,
+    projectRoots,
+  );
 }
 
 function onDisconnected() {

packages/react-devtools-extensions/src/main/fetchFileWithCaching.js

@@ -1,5 +1,6 @@
 /* global chrome */
 
+import {normalizeUrl} from 'react-devtools-shared/src/utils';
 import {__DEBUG__} from 'react-devtools-shared/src/constants';
 
 let debugIDCounter = 0;
@@ -107,17 +108,35 @@ const fetchFromPage = async (url, resolve, reject) => {
   });
 };
 
-// Fetching files from the extension won't make use of the network cache
-// for resources that have already been loaded by the page.
-// This helper function allows the extension to request files to be fetched
-// by the content script (running in the page) to increase the likelihood of a cache hit.
-const fetchFileWithCaching = url => {
+// 1. Check if resource is available via chrome.devtools.inspectedWindow.getResources
+// 2. Check if resource was loaded previously and available in network cache via chrome.devtools.network.getHAR
+// 3. Fallback to fetching directly from the page context (from backend)
+async function fetchFileWithCaching(url: string): Promise<string> {
+  if (__IS_CHROME__ || __IS_EDGE__) {
+    const resources = await new Promise(resolve =>
+      chrome.devtools.inspectedWindow.getResources(r => resolve(r)),
+    );
+
+    const normalizedReferenceURL = normalizeUrl(url);
+    const resource = resources.find(r => r.url === normalizedReferenceURL);
+
+    if (resource != null) {
+      const content = await new Promise(resolve =>
+        resource.getContent(fetchedContent => resolve(fetchedContent)),
+      );
+
+      if (content) {
+        return content;
+      }
+    }
+  }
+
   return new Promise((resolve, reject) => {
     // Try fetching from the Network cache first.
     // If DevTools was opened after the page started loading, we may have missed some requests.
     // So fall back to a fetch() from the page and hope we get a cached response that way.
     fetchFromNetworkCache(url, resolve, reject);
   });
-};
+}
 
 export default fetchFileWithCaching;

packages/react-devtools-extensions/src/main/index.js

@@ -128,34 +128,13 @@ function createBridgeAndStore() {
     }
   };
 
-  const viewElementSourceFunction = id => {
-    const rendererID = store.getRendererIDForElement(id);
-    if (rendererID != null) {
-      // Ask the renderer interface to determine the component function,
-      // and store it as a global variable on the window
-      bridge.send('viewElementSource', {id, rendererID});
+  const viewElementSourceFunction = (source, symbolicatedSource) => {
+    const {sourceURL, line, column} = symbolicatedSource
+      ? symbolicatedSource
+      : source;
 
-      setTimeout(() => {
-        // Ask Chrome to display the location of the component function,
-        // or a render method if it is a Class (ideally Class instance, not type)
-        // assuming the renderer found one.
-        chrome.devtools.inspectedWindow.eval(`
-                if (window.$type != null) {
-                  if (
-                    window.$type &&
-                    window.$type.prototype &&
-                    window.$type.prototype.isReactComponent
-                  ) {
-                    // inspect Component.render, not constructor
-                    inspect(window.$type.prototype.render);
-                  } else {
-                    // inspect Functional Component
-                    inspect(window.$type);
-                  }
-                }
-              `);
-      }, 100);
-    }
+    // We use 1-based line and column, Chrome expects them 0-based.
+    chrome.devtools.panels.openResource(sourceURL, line - 1, column - 1);
   };
 
   // TODO (Webpack 5) Hopefully we can remove this prop after the Webpack 5 migration.
@@ -183,17 +162,14 @@ function createBridgeAndStore() {
         store,
         warnIfUnsupportedVersionDetected: true,
         viewAttributeSourceFunction,
+        // Firefox doesn't support chrome.devtools.panels.openResource yet
+        canViewElementSourceFunction: () => __IS_CHROME__ || __IS_EDGE__,
         viewElementSourceFunction,
-        viewUrlSourceFunction,
       }),
     );
   };
 }
 
-const viewUrlSourceFunction = (url, line, col) => {
-  chrome.devtools.panels.openResource(url, line, col);
-};
-
 function ensureInitialHTMLIsCleared(container) {
   if (container._hasInitialHTMLBeenCleared) {
     return;

packages/react-devtools-extensions/webpack.config.js

@@ -39,6 +39,7 @@ const LOGGING_URL = process.env.LOGGING_URL || null;
 const IS_CHROME = process.env.IS_CHROME === 'true';
 const IS_FIREFOX = process.env.IS_FIREFOX === 'true';
 const IS_EDGE = process.env.IS_EDGE === 'true';
+const IS_INTERNAL_VERSION = process.env.FEATURE_FLAG_TARGET === 'extension-fb';
 
 const featureFlagTarget = process.env.FEATURE_FLAG_TARGET || 'extension-oss';
 
@@ -119,6 +120,7 @@ module.exports = {
       __IS_CHROME__: IS_CHROME,
       __IS_FIREFOX__: IS_FIREFOX,
       __IS_EDGE__: IS_EDGE,
+      __IS_INTERNAL_VERSION__: IS_INTERNAL_VERSION,
       'process.env.DEVTOOLS_PACKAGE': `"react-devtools-extensions"`,
       'process.env.DEVTOOLS_VERSION': `"${DEVTOOLS_VERSION}"`,
       'process.env.EDITOR_URL': EDITOR_URL != null ? `"${EDITOR_URL}"` : null,

packages/react-devtools-shared/package.json

@@ -19,6 +19,7 @@
     "@reach/tooltip": "^0.16.0",
     "clipboard-js": "^0.3.6",
     "compare-versions": "^5.0.3",
+    "jsc-safe-url": "^0.2.4",
     "json5": "^2.1.3",
     "local-storage-fallback": "^4.1.1",
     "lodash.throttle": "^4.1.1",

packages/react-devtools-shared/src/backendAPI.js

@@ -261,7 +261,9 @@ export function convertInspectedElementBackendToFrontend(
     rendererPackageName,
     rendererVersion,
     rootType,
-    source,
+    // Previous backend implementations (<= 5.0.1) have a different interface for Source, with fileName.
+    // This gates the source features for only compatible backends: >= 5.0.2
+    source: source && source.sourceURL ? source : null,
     type,
     owners:
       owners === null