move to passing informatoion througsh metro

packages/vscode-extension/lib/metro_helpers.js

@@ -42,16 +42,14 @@ function adaptMetroConfig(config) {
       }
     } else if (module.path === "__env__") {
       // this handles @expo/env plugin, which is used to inject environment variables
-      // the code below instantiates a global variable __EXPO_ENV_PRELUDE_LINES__ that stores
-      // the number of lines in the prelude. This is used to calculate the line number offset
+      // the code below exposes the number of lines in the prelude.
+      // This is used to calculate the line number offset
       // when reporting line numbers from the JS runtime, breakpoints
       // and uncaught exceptions. The reason why this is needed, is that
       // metro doesn't include __env__ prelude in the source map resulting in the source map
-      // transformation getting shifted by the number of lines in the prelude.
-      const expoEnvCode = module.output[0].data.code;
-      if (!expoEnvCode.includes("__EXPO_ENV_PRELUDE_LINES__")) {
-        module.output[0].data.code = `${expoEnvCode};var __EXPO_ENV_PRELUDE_LINES__=${module.output[0].data.lineCount};`;
-      }
+      // transformation getting shifted by the number of lines in the expo generated prelude.
+      process.stdout.write(JSON.stringify({ type: "RNIDE_expo_env_prelude_lines", lineOffset: module.output[0].data.lineCount }));
+      process.stdout.write("\n");
     }
     return origProcessModuleFilter(module);
   };

packages/vscode-extension/src/debugging/DebugAdapter.ts

@@ -86,6 +86,7 @@ export class DebugAdapter extends DebugSession {
   private projectPathAlias?: string;
   private threads: Array<Thread> = [];
   private sourceMaps: Array<[string, string, SourceMapConsumer, number]> = [];
+  private lineOffset: number;
   private linesStartAt1 = true;
   private columnsStartAt1 = true;
 
@@ -97,6 +98,7 @@ export class DebugAdapter extends DebugSession {
     this.absoluteProjectPath = configuration.absoluteProjectPath;
     this.projectPathAlias = configuration.projectPathAlias;
     this.connection = new WebSocket(configuration.websocketAddress);
+    this.lineOffset = configuration.lineOffset;
 
     this.connection.on("open", () => {
       // the below catch handler is used to ignore errors coming from non critical CDP messages we
@@ -152,28 +154,29 @@ export class DebugAdapter extends DebugSession {
             const sourceMap = JSON.parse(decodedData);
             const consumer = await new SourceMapConsumer(sourceMap);
 
-            const sourceFile = await (await fetch(message.params.url)).text();
-            const lineOffsetRegex = /__EXPO_ENV_PRELUDE_LINES__=(\d+);/;
-            const match = sourceFile.match(lineOffsetRegex);
-            const lineOffset = Number(match ? match[1] : null);
+            // This is a heuristic that checks if the source map should contain __env__
+            // module that is added by expo, but not reported in the source map
+            const isFileWithOffset = sourceMap.sources.includes("__prelude__");
+
             // This line is here because of a problem with sourcemaps for expo projects,
             // that was addressed in this PR https://github.com/expo/expo/pull/29463,
             // unfortunately it still requires changes to metro that were attempted here
             // https://github.com/facebook/metro/pull/1284 we should monitor the situation
             // in upcoming versions and if the changes are still not added bump the version below.
-            const shouldApplyOffset = semver.lte(getReactNativeVersion(), "0.76.0");
-            if (lineOffset && shouldApplyOffset) {
+            const shouldApplyOffset =
+              semver.lte(getReactNativeVersion(), "0.76.0") && isFileWithOffset;
+            if (this.lineOffset !== 0 && shouldApplyOffset) {
               Logger.debug(
                 "Expo prelude lines were detected and an offset was set to:",
-                lineOffset
+                this.lineOffset
               );
             }
 
             this.sourceMaps.push([
               message.params.url,
               message.params.scriptId,
               consumer,
-              shouldApplyOffset ? lineOffset : 0,
+              shouldApplyOffset ? this.lineOffset : 0,
             ]);
             this.updateBreakpointsInSource(message.params.url, consumer);
           }

packages/vscode-extension/src/debugging/DebugSession.ts

@@ -56,6 +56,7 @@ export class DebugSession implements Disposable {
         websocketAddress: websocketAddress,
         absoluteProjectPath: getAppRootFolder(),
         projectPathAlias: this.metro.isUsingNewDebugger ? "/[metro-project]" : undefined,
+        lineOffset: this.metro.expoPreludeLineOffset,
       },
       {
         suppressDebugStatusbar: true,

packages/vscode-extension/src/project/metro.ts

@@ -46,6 +46,7 @@ type MetroEvent =
       transformedFileCount: number;
       totalFileCount: number;
     }
+  | { type: "RNIDE_expo_env_prelude_lines"; lineOffset: number }
   | {
       type: "RNIDE_initialize_done";
       port: number;
@@ -66,6 +67,7 @@ export class Metro implements Disposable {
   private _port = 0;
   private startPromise: Promise<void> | undefined;
   private usesNewDebugger?: Boolean;
+  private _expoPreludeLineOffset: number = 0;
 
   constructor(private readonly devtools: Devtools, private readonly delegate: MetroDelegate) {}
 
@@ -80,6 +82,10 @@ export class Metro implements Disposable {
     return this._port;
   }
 
+  public get expoPreludeLineOffset() {
+    return this._expoPreludeLineOffset;
+  }
+
   public dispose() {
     this.subprocess?.kill(9);
   }
@@ -207,6 +213,10 @@ export class Metro implements Disposable {
           }
 
           switch (event.type) {
+            case "RNIDE_expo_env_prelude_lines":
+              this._expoPreludeLineOffset = event.lineOffset;
+              Logger.debug("Expo prelude line offset was set to: ", this._expoPreludeLineOffset);
+              break;
             case "RNIDE_initialize_done":
               this._port = event.port;
               Logger.info(`Metro started on port ${this._port}`);