From 8e6ef2e735f52d08c3b47e384e0d1c82d138c98c Mon Sep 17 00:00:00 2001
From: Tiancheng Xu <44307608+Tiancheng-Xu@users.noreply.github.com>
Date: Wed, 16 Sep 2026 06:56:50 -0400
Subject: [PATCH 1/2] fix(node): preserve stdio fds for sync child processes

---
 ext/node/polyfills/internal/child_process.ts | 11 ++++++++---
 tests/unit_node/child_process_test.ts        | 10 ++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/ext/node/polyfills/internal/child_process.ts b/ext/node/polyfills/internal/child_process.ts
index d9f71bbdc66629..dcc23192a191fe 100644
--- a/ext/node/polyfills/internal/child_process.ts
+++ b/ext/node/polyfills/internal/child_process.ts
@@ -959,6 +959,9 @@ function streamHandleFd(stream) {
   if (handle && typeof handle.fd === "number" && handle.fd >= 0) {
     return handle.fd;
   }
+  if (typeof stream.fd === "number" && stream.fd >= 0) {
+    return stream.fd;
+  }
   return -1;
 }
 
@@ -997,9 +1000,11 @@ function toDenoStdio(
     // another child's stdin shares the underlying OS pipe.
     const fd = streamHandleFd(pipe);
     if (fd >= 0) {
-      pipe[kChildStdioUsedAsInput] = true;
-      pipe.pause();
-      pipe._handle?.readStop?.();
+      if (typeof pipe.pause === "function") {
+        pipe[kChildStdioUsedAsInput] = true;
+        pipe.pause();
+        pipe._handle?.readStop?.();
+      }
       return fd;
     }
     // For streams without a usable fd, create a pipe and set up JS-level
diff --git a/tests/unit_node/child_process_test.ts b/tests/unit_node/child_process_test.ts
index 40047745eeebea..214cbc3fa8b6a6 100644
--- a/tests/unit_node/child_process_test.ts
+++ b/tests/unit_node/child_process_test.ts
@@ -1050,6 +1050,16 @@ Deno.test(function spawnSyncStdioUndefined() {
   assertEquals(ret.stderr.toString("utf-8").trim(), "world");
 });
 
+Deno.test(function spawnSyncProcessStdioUsesFileDescriptors() {
+  const ret = spawnSync(Deno.execPath(), ["eval", ""], {
+    stdio: [process.stdin, process.stdout, process.stderr],
+  });
+
+  assertEquals(ret.status, 0);
+  assertEquals(ret.stdout, null);
+  assertEquals(ret.stderr, null);
+});
+
 Deno.test(function spawnSyncExitNonZero() {
   const ret = spawnSync(
     `"${Deno.execPath()}" eval "Deno.exit(22)"`,

From 5e8f2ddadf3c2bc9856f7bb8f47590212095d32c Mon Sep 17 00:00:00 2001
From: Tiancheng-Xu <44307608+Tiancheng-Xu@users.noreply.github.com>
Date: Mon, 21 Sep 2026 02:08:47 -0400
Subject: [PATCH 2/2] fix(node): run piped stdin as CommonJS

---
 ext/node/ops/node_cli_parser.rs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/ext/node/ops/node_cli_parser.rs b/ext/node/ops/node_cli_parser.rs
index 3aa6c3c7894069..2d4ea8835d04b8 100644
--- a/ext/node/ops/node_cli_parser.rs
+++ b/ext/node/ops/node_cli_parser.rs
@@ -109,12 +109,17 @@ pub fn op_node_translate_cli_args(
   script_in_npm_package: bool,
   wrap_eval: bool,
 ) -> Result<TranslatedArgs, CliParserError> {
-  // If no args, return early with run -A -
+  // If no args, return early with run -A --ext=cjs -
   // `-` tells Deno to read from stdin, matching Node.js behavior where
-  // `node` with no args reads and executes piped stdin.
+  // `node` with no args reads and executes piped stdin as CommonJS.
   if args.is_empty() {
     return Ok(TranslatedArgs {
-      deno_args: vec!["run".to_string(), "-A".to_string(), "-".to_string()],
+      deno_args: vec![
+        "run".to_string(),
+        "-A".to_string(),
+        "--ext=cjs".to_string(),
+        "-".to_string(),
+      ],
       node_options: vec![],
       ca_stores: None,
       use_openssl_ca: false,