stdio: implement manual start for ReadStream

All stdio ReadStream's use manual start to avoid
consuming data for example when a process
execs/spawns

Refs: #36251

Author: mmomtchev

lib/internal/bootstrap/switches/is_main_thread.js

@@ -157,7 +157,11 @@ function getStdin() {
 
     case 'FILE':
       const fs = require('fs');
-      stdin = new fs.ReadStream(null, { fd: fd, autoClose: false });
+      stdin = new fs.ReadStream(null, {
+        fd: fd,
+        autoClose: false,
+        manualStart: true
+      });
       break;
 
     case 'PIPE':

lib/internal/streams/readable.js

@@ -196,7 +196,8 @@ function Readable(options) {
   Stream.call(this, options);
 
   destroyImpl.construct(this, () => {
-    maybeReadMore(this, this._readableState);
+    if (!options || !options.manualStart)
+      maybeReadMore(this, this._readableState);
   });
 }
 

test/parallel/test-stdin-from-file-spawn.js

@@ -0,0 +1,34 @@
+'use strict';
+const common = require('../common');
+const process = require('process');
+if (process.platform !== 'linux' && process.platform !== 'darwin')
+  common.skip('This is an UNIX-only test');
+
+const { execSync } = require('child_process');
+const fs = require('fs');
+const path = require('path');
+const tmpdir = require('../common/tmpdir');
+
+const tmpDir = tmpdir.path;
+tmpdir.refresh();
+const tmpCmdFile = path.join(tmpDir, 'test-stdin-from-file-spawn-cmd');
+const tmpJsFile = path.join(tmpDir, 'test-stdin-from-file-spawn.js');
+fs.writeFileSync(tmpCmdFile, 'echo hello');
+fs.writeFileSync(tmpJsFile, `
+'use strict';
+const { spawn } = require('child_process');
+// Reference the object to invoke the getter
+process.stdin;
+setTimeout(() => {
+  let ok = false;
+  const child = spawn(process.env.SHELL, [], { stdio: ['inherit', 'pipe'] });
+  child.stdout.on('data', () => {
+    ok = true;
+  });
+  child.on('close', () => {
+    process.exit(ok ? 0 : -1);
+  });
+}, 100);
+`);
+
+execSync(`${process.argv[0]} ${tmpJsFile} < ${tmpCmdFile}`);