fix(ext/node): support stdin: "inherit" in node:child_process (#23110)

Fixes https://github.com/denoland/deno/issues/23051

ext/node/polyfills/internal/child_process.ts

@@ -866,7 +866,7 @@ export function spawnSync(
     windowsVerbatimArguments = false,
   } = options;
   const [
-    _stdin_ = "pipe", // TODO(bartlomieju): use this?
+    stdin_ = "pipe",
     stdout_ = "pipe",
     stderr_ = "pipe",
     _channel, // TODO(kt3k): handle this correctly
@@ -881,6 +881,7 @@ export function spawnSync(
       env: mapValues(env, (value) => value.toString()),
       stdout: toDenoStdio(stdout_),
       stderr: toDenoStdio(stderr_),
+      stdin: stdin_ == "inherit" ? "inherit" : "null",
       uid,
       gid,
       windowsRawArguments: windowsVerbatimArguments,

tests/unit_node/child_process_test.ts

@@ -823,3 +823,35 @@ Deno.test(function spawnCommandNullStdioArray() {
 
   assertEquals(ret.status, 0);
 });
+
+Deno.test(
+  function stdinInherit() {
+    const script = `
+      function timeoutPromise(promise, timeout) {
+        return new Promise((resolve, reject) => {
+          const timeoutId = setTimeout(() => {
+            Deno.exit(69);
+          }, timeout);
+          promise.then((value) => {
+            clearTimeout(timeoutId);
+            resolve(value);
+          }, (reason) => {
+            clearTimeout(timeoutId);
+            reject(reason);
+          });
+        });
+      }
+
+      await timeoutPromise(Deno.stdin.read(new Uint8Array(1)), 100)
+    `;
+
+    const output = spawnSync(Deno.execPath(), ["eval", script], {
+      stdio: "inherit",
+    });
+
+    // We want to timeout to occur because the stdin isn't 'null'
+    assertEquals(output.status, 69);
+    assertEquals(output.stdout, null);
+    assertEquals(output.stderr, null);
+  },
+);