Mock process before importing

packages/compiler/src/server/mock-process.ts

@@ -0,0 +1,50 @@
+import { Buffer } from "node:buffer";
+import { Readable as ReadableStream, Writable as WritableStream } from "node:stream";
+
+export function mockProcess(path: string): NodeJS.Process {
+  return {
+    ...process,
+    exit: () => {
+      throw new Error(`Importing ${path} tried to call process.exit`);
+    },
+    stdin: readableNoopStream() as any,
+    stdout: writableNoopStream() as any,
+    on: (() => {}) as any,
+  };
+}
+
+function readableNoopStream({ size = 0 } = {}) {
+  let producedSize = 0;
+
+  return new ReadableStream({
+    read(readSize) {
+      let shouldEnd = false;
+
+      if (producedSize + readSize >= size) {
+        readSize = size - producedSize;
+        shouldEnd = true;
+      }
+
+      setImmediate(() => {
+        if (size === 0) {
+          this.push(null);
+        }
+
+        producedSize += readSize;
+        this.push(Buffer.alloc(readSize));
+
+        if (shouldEnd) {
+          this.push(null);
+        }
+      });
+    },
+  });
+}
+
+function writableNoopStream() {
+  return new WritableStream({
+    write(chunk, encding, callback) {
+      setImmediate(callback);
+    },
+  });
+}

packages/compiler/src/server/npm-package-provider.ts

@@ -202,22 +202,8 @@ export class NpmPackage {
         return undefined;
       }
       const entrypoint = module.type === "file" ? module.path : module.mainFile;
-      const oldExit = process.exit;
-      try {
-        // override process.exit to prevent the process from exiting because of it's called in loaded js file
-        let result: any;
-        process.exit = (() => {
-          // for module that calls process.exit when being imported, create an empty object as it's exports to avoid load it again
-          result = {};
-          throw new Error(
-            "process.exit is called unexpectedly when loading js file: " + entrypoint,
-          );
-        }) as any;
-        const [file] = await loadJsFile(host, entrypoint, NoTarget);
-        return result ?? file?.esmExports;
-      } finally {
-        process.exit = oldExit;
-      }
+      const [file] = await loadJsFile(host, entrypoint, NoTarget);
+      return file?.esmExports;
     } catch (e) {
       return undefined;
     }

packages/compiler/src/server/server.ts

@@ -15,6 +15,7 @@ import {
 import { NodeHost } from "../core/node-host.js";
 import { typespecVersion } from "../manifest.js";
 import { createClientConfigProvider } from "./client-config-provider.js";
+import { mockProcess } from "./mock-process.js";
 import { createServer } from "./serverlib.js";
 import { CustomRequestName, Server, ServerHost, ServerLog } from "./types.js";
 
@@ -48,7 +49,19 @@ function main() {
   console.error = (data: any, ...args: any[]) => connection.console.error(format(data, ...args));
 
   const host: ServerHost = {
-    compilerHost: NodeHost,
+    compilerHost: {
+      ...NodeHost,
+      getJsImport: (path: string) => {
+        const oldProcess = globalThis.process;
+        try {
+          globalThis.process = mockProcess(path) as any;
+          const result = NodeHost.getJsImport(path);
+          return result;
+        } finally {
+          globalThis.process.stdin = oldProcess.stdin;
+        }
+      },
+    },
     sendDiagnostics(params: PublishDiagnosticsParams) {
       void connection.sendDiagnostics(params);
     },