Accept bundle and symbolication requests in JSC-safe format (//& in place of ?)

Summary:
The first part of implementing react-native-community/discussions-and-proposals#646 to address facebook/react-native#36794.

This allows Metro to respond to bundle and symbolication requests that use URLs with `//&` in place of `?` as a query delimiter.

```
**[Feature]**: Support URLs for both bundling and symbolication requests using `//&` instead of `?` as a query string delimiter
```

(Note: This does *not* add support for registering HMR entry points in the JSC-safe format - that's not necessary at this point, if at all, and I'm keen to minimise the footprint of this stack for easier backporting.)

Reviewed By: huntie

Differential Revision: D45983877

fbshipit-source-id: e799f76cd26c2ca8026b4d1bf70a582814ae1790

Author: robhogan

docs/Configuration.md

@@ -615,7 +615,7 @@ The possibility to add custom middleware to the server response chain.
 
 Type: `string => string`
 
-A function that will be called every time Metro processes a URL. Metro will use the return value of this function as if it were the original URL provided by the client. This applies to all incoming HTTP requests (after any custom middleware), as well as bundle URLs in `/symbolicate` request payloads and within the hot reloading protocol.
+A function that will be called every time Metro processes a URL, after normalization of non-standard query-string delimiters using [`jsc-safe-url`](https://www.npmjs.com/package/jsc-safe-url). Metro will use the return value of this function as if it were the original URL provided by the client. This applies to all incoming HTTP requests (after any custom middleware), as well as bundle URLs in `/symbolicate` request payloads and within the hot reloading protocol.
 
 #### `runInspectorProxy`
 

packages/metro/package.json

@@ -33,6 +33,7 @@
     "image-size": "^1.0.2",
     "invariant": "^2.2.4",
     "jest-worker": "^27.2.0",
+    "jsc-safe-url": "^0.2.2",
     "lodash.throttle": "^4.1.1",
     "metro-babel-transformer": "0.76.4",
     "metro-cache": "0.76.4",

packages/metro/src/Server.js

@@ -65,6 +65,8 @@ const {codeFrameColumns} = require('@babel/code-frame');
 const MultipartResponse = require('./Server/MultipartResponse');
 const debug = require('debug')('Metro:Server');
 const fs = require('graceful-fs');
+const invariant = require('invariant');
+const jscSafeUrl = require('jsc-safe-url');
 const {
   Logger,
   Logger: {createActionStartEntry, createActionEndEntry, log},
@@ -489,14 +491,19 @@ class Server {
     return parseOptionsFromUrl(url, new Set(this._config.resolver.platforms));
   }
 
+  _rewriteAndNormalizeUrl(requestUrl: string): string {
+    return jscSafeUrl.toNormalUrl(
+      this._config.server.rewriteRequestUrl(jscSafeUrl.toNormalUrl(requestUrl)),
+    );
+  }
+
   async _processRequest(
     req: IncomingMessage,
     res: ServerResponse,
     next: (?Error) => mixed,
   ) {
     const originalUrl = req.url;
-    req.url = this._config.server.rewriteRequestUrl(req.url);
-
+    req.url = this._rewriteAndNormalizeUrl(req.url);
     const urlObj = url.parse(req.url, true);
     const {host} = req.headers;
     debug(
@@ -1112,19 +1119,33 @@ class Server {
       /* $FlowFixMe: where is `rawBody` defined? Is it added by the `connect` framework? */
       const body = await req.rawBody;
       const parsedBody = JSON.parse(body);
-      const stack = parsedBody.stack.map(frame => {
-        if (frame.file && frame.file.includes('://')) {
+
+      const rewriteAndNormalizeStackFrame = <T>(
+        frame: T,
+        lineNumber: number,
+      ): T => {
+        invariant(
+          frame != null && typeof frame === 'object',
+          'Bad stack frame at line %d, expected object, received: %s',
+          lineNumber,
+          typeof frame,
+        );
+        const frameFile = frame.file;
+        if (typeof frameFile === 'string' && frameFile.includes('://')) {
           return {
             ...frame,
-            file: this._config.server.rewriteRequestUrl(frame.file),
+            file: this._rewriteAndNormalizeUrl(frameFile),
           };
         }
         return frame;
-      });
+      };
+
+      const stack = parsedBody.stack.map(rewriteAndNormalizeStackFrame);
       // In case of multiple bundles / HMR, some stack frames can have different URLs from others
       const urls = new Set<string>();
 
       stack.forEach(frame => {
+        // These urls have been rewritten and normalized above.
         const sourceUrl = frame.file;
         // Skip `/debuggerWorker.js` which does not need symbolication.
         if (
@@ -1139,8 +1160,11 @@ class Server {
 
       debug('Getting source maps for symbolication');
       const sourceMaps = await Promise.all(
-        // $FlowFixMe[method-unbinding] added when improving typing for this parameters
-        Array.from(urls.values()).map(this._explodedSourceMapForURL, this),
+        Array.from(urls.values()).map(normalizedUrl =>
+          this._explodedSourceMapForBundleOptions(
+            this._parseOptions(normalizedUrl),
+          ),
+        ),
       );
 
       debug('Performing fast symbolication');
@@ -1168,20 +1192,17 @@ class Server {
     }
   }
 
-  async _explodedSourceMapForURL(reqUrl: string): Promise<ExplodedSourceMap> {
-    const options = parseOptionsFromUrl(
-      reqUrl,
-      new Set(this._config.resolver.platforms),
-    );
-
+  async _explodedSourceMapForBundleOptions(
+    bundleOptions: BundleOptions,
+  ): Promise<ExplodedSourceMap> {
     const {
       entryFile,
       graphOptions,
       onProgress,
       resolverOptions,
       serializerOptions,
       transformOptions,
-    } = splitBundleOptions(options);
+    } = splitBundleOptions(bundleOptions);
 
     /**
      * `entryFile` is relative to projectRoot, we need to use resolution function