Remove setBlocking calls and simplify file-redirect approach

Remove fragile process.stdout._handle.setBlocking calls from CLI test
commands. Revert the preload workaround in repo-tools since the root
cause is removed.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Made-with: Cursor

packages/cli/src/modules/test/commands/package/test.ts

@@ -87,11 +87,6 @@ export default async (_opts: OptionValues, cmd: Command) => {
     }--no-node-snapshot`;
   }
 
-  // This ensures that the process doesn't exit too early before stdout is flushed
-  if (args.includes('--help')) {
-    (process.stdout as any)._handle.setBlocking(true);
-  }
-
   // Because of the ongoing migration to v30 of jest, jest is no longer hard-depended to allow
   // opt-in migration. Users instead need to add jest as a devDependency themselves and specify
   // the version they want. This prints a helpful error message if jest is not found, i.e. they

packages/cli/src/modules/test/commands/repo/test.ts

@@ -304,11 +304,9 @@ export async function command(opts: OptionValues, cmd: Command): Promise<void> {
     }--no-node-snapshot`;
   }
 
-  // This ensures that the process doesn't exit too early before stdout is flushed
   if (args.includes('--jest-help')) {
     removeOptionArg(args, '--jest-help');
     args.push('--help');
-    (process.stdout as any)._handle.setBlocking(true);
   }
 
   // This code path is enabled by the --successCache flag, which is specific to

packages/repo-tools/src/commands/util.ts

@@ -15,42 +15,10 @@
  */
 
 import { spawnSync } from 'node:child_process';
-import {
-  openSync,
-  closeSync,
-  readFileSync,
-  unlinkSync,
-  writeFileSync,
-} from 'node:fs';
+import { openSync, closeSync, readFileSync, unlinkSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 
-// Preload script that stubs process.stdout._handle when stdout is backed by a
-// file (SyncWriteStream). Some CLI code accesses _handle.setBlocking directly
-// and would crash without this.
-const preloadContent = `
-if (process.stdout && !process.stdout._handle) {
-  process.stdout._handle = { setBlocking() {} };
-}
-`;
-
-let preloadPath: string | undefined;
-
-function getPreloadPath() {
-  if (!preloadPath) {
-    preloadPath = join(tmpdir(), `backstage-stdout-preload-${process.pid}.cjs`);
-    writeFileSync(preloadPath, preloadContent);
-    process.on('exit', () => {
-      try {
-        unlinkSync(preloadPath!);
-      } catch {
-        /* ignore */
-      }
-    });
-  }
-  return preloadPath;
-}
-
 /**
  * Redirect stdout to a temp file so that Node.js creates a SyncWriteStream
  * (synchronous writes) in the child instead of an async pipe stream. This
@@ -67,15 +35,11 @@ export function createBinRunner(cwd: string, path: string) {
     const outFd = openSync(outPath, 'w');
 
     try {
-      const result = spawnSync(
-        'node',
-        ['--require', getPreloadPath(), ...args],
-        {
-          cwd,
-          stdio: ['ignore', outFd, 'pipe'],
-          maxBuffer: 10 * 1024 * 1024,
-        },
-      );
+      const result = spawnSync('node', args, {
+        cwd,
+        stdio: ['ignore', outFd, 'pipe'],
+        maxBuffer: 10 * 1024 * 1024,
+      });
 
       closeSync(outFd);
       const stdout = readFileSync(outPath, 'utf8');