feat(runtime/command): make stdin default to inherit for spawn() (#17334)

Closes #17230

cli/tests/unit/command_test.ts

@@ -83,6 +83,24 @@ Deno.test(
   },
 );
 
+Deno.test(
+  { permissions: { run: true, read: true } },
+  async function commandStdinPiped() {
+    const command = new Deno.Command(Deno.execPath(), {
+      args: ["info"],
+      stdout: "null",
+      stderr: "null",
+    });
+    const child = command.spawn();
+
+    assertThrows(() => child.stdin, TypeError, "stdin is not piped");
+    assertThrows(() => child.stdout, TypeError, "stdout is not piped");
+    assertThrows(() => child.stderr, TypeError, "stderr is not piped");
+
+    await child.status;
+  },
+);
+
 Deno.test(
   { permissions: { run: true, read: true } },
   async function commandStdoutPiped() {

cli/tsc/dts/lib.deno.unstable.d.ts

@@ -1640,7 +1640,8 @@ declare namespace Deno {
 
     /** How `stdin` of the spawned process should be handled.
      *
-     * Defaults to `"null"`. */
+     * Defaults to `"inherit"` for `output` & `outputSync`,
+     * and `"inherit"` for `spawn`. */
     stdin?: "piped" | "inherit" | "null";
     /** How `stdout` of the spawned process should be handled.
      *

runtime/js/40_spawn.js

@@ -315,6 +315,7 @@
           ...(this.#options ?? {}),
           stdout: this.#options?.stdout ?? "inherit",
           stderr: this.#options?.stderr ?? "inherit",
+          stdin: this.#options?.stdin ?? "inherit",
         };
         return spawnChild(this.#command, options);
       }