fix(node): map stdio [0, 1, 2] to "inherit" (#19352)

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Internally, `node-tap` spawns a child process with `stdio: [0, 1, 2]`.
Whilst we don't support passing fd numbers as an argument so far, it
turns out that `[0, 1, 2]` is equivalent to `"inherit"` which we already
support. See: https://nodejs.org/api/child_process.html#optionsstdio

Mapping it to `"inherit"` is fine for us and gets us one step closer in
getting `node-tap` working. I'm now at the stage where already the
coverage table is shown 🎉

3 files changed, 44 insertions, 0 deletions

diff --git a/cli/tests/unit_node/child_process_test.ts b/cli/tests/unit_node/child_process_test.ts
index d4a2a4cc6..f8de5b6f6 100644
--- a/cli/tests/unit_node/child_process_test.ts
+++ b/cli/tests/unit_node/child_process_test.ts
@@ -600,6 +600,28 @@ Deno.test(
   },
 );
 
+Deno.test(
+  "[node/child_process spawn] supports stdio [0, 1, 2] option",
+  async () => {
+    const cmdFinished = deferred();
+    let output = "";
+    const script = path.join(
+      path.dirname(path.fromFileUrl(import.meta.url)),
+      "testdata",
+      "child_process_stdio_012.js",
+    );
+    const cp = spawn(Deno.execPath(), ["run", "-A", script]);
+    cp.stdout?.on("data", (data) => {
+      output += data;
+    });
+    cp.on("close", () => cmdFinished.resolve());
+    await cmdFinished;
+
+    assertStringIncludes(output, "foo");
+    assertStringIncludes(output, "close");
+  },
+);
+
 Deno.test({
   name: "[node/child_process spawn] supports SIGIOT signal",
   ignore: Deno.build.os === "windows",
diff --git a/cli/tests/unit_node/testdata/child_process_stdio_012.js b/cli/tests/unit_node/testdata/child_process_stdio_012.js
new file mode 100644
index 000000000..682d8a084
--- /dev/null
+++ b/cli/tests/unit_node/testdata/child_process_stdio_012.js
@@ -0,0 +1,15 @@
+import childProcess from "node:child_process";
+import process from "node:process";
+import * as path from "node:path";
+
+const script = path.join(
+  path.dirname(path.fromFileUrl(import.meta.url)),
+  "node_modules",
+  "foo",
+  "index.js",
+);
+
+const child = childProcess.spawn(process.execPath, [script], {
+  stdio: [0, 1, 2],
+});
+child.on("close", () => console.log("close"));
diff --git a/ext/node/polyfills/internal/child_process.ts b/ext/node/polyfills/internal/child_process.ts
index 365af4add..d4acf1db2 100644
--- a/ext/node/polyfills/internal/child_process.ts
+++ b/ext/node/polyfills/internal/child_process.ts
@@ -469,6 +469,13 @@ function normalizeStdioOption(
   ...Array<Stream | NodeStdio | number>,
 ] {
   if (Array.isArray(stdio)) {
+    // `[0, 1, 2]` is equivalent to `"inherit"`
+    if (
+      stdio.length === 3 && stdio[0] === 0 && stdio[1] === 1 && stdio[2] === 2
+    ) {
+      return ["inherit", "inherit", "inherit"];
+    }
+
     // At least 3 stdio must be created to match node
     while (stdio.length < 3) {
       ArrayPrototypePush(stdio, undefined);