fix(node/process): null is not returned when reaching end-of-file in stdin

node/_process/streams.mjs

@@ -103,7 +103,7 @@ export const stdout = stdio.stdout = createWritableStdioStream(
 
 /** https://nodejs.org/api/process.html#process_process_stdin */
 export const stdin = stdio.stdin = new Readable({
-  highWaterMark: 0,
+  highWaterMark: Deno.isatty?.(Deno.stdin?.rid) ? 0 : 64 * 1024,
   emitClose: false,
   read(size) {
     const p = Buffer.alloc(size || 16 * 1024);

node/process_test.ts

@@ -326,6 +326,66 @@ Deno.test({
   },
 });
 
+Deno.test({
+  name: "process.stdin readable with a TTY",
+  ignore: !Deno.isatty(Deno.stdin.rid),
+  async fn() {
+    const promise = deferred();
+    const expected = ["foo", "bar", null, "end"];
+    const data: (string | null)[] = [];
+
+    process.stdin.setEncoding("utf8");
+    process.stdin.on("readable", () => {
+      data.push(process.stdin.read());
+    });
+    process.stdin.on("end", () => {
+      data.push("end");
+    });
+
+    process.stdin.push("foo");
+    process.nextTick(() => {
+      process.stdin.push("bar");
+      process.nextTick(() => {
+        process.stdin.push(null);
+        promise.resolve();
+      });
+    });
+
+    await promise;
+    assertEquals(process.stdin.readableHighWaterMark, 0);
+    assertEquals(data, expected);
+  },
+});
+
+Deno.test({
+  name: "process.stdin readable with piping a file",
+  async fn() {
+    const expected = ["65536", "foo", "bar", "null", "end"];
+    const scriptPath = "./node/testdata/process_stdin.ts";
+    const file = await Deno.readFile(`./node/testdata/process_stdin_dummy.txt`);
+
+    const command = new Deno.Command(Deno.execPath(), {
+      args: ["run", scriptPath],
+      stdin: "piped",
+      stdout: "piped",
+      stderr: "null",
+    });
+    const child = command.spawn();
+
+    const writer = await child.stdin.getWriter();
+    writer.ready
+      .then(() => writer.write(file))
+      .then(() => writer.releaseLock())
+      .then(() => child.stdin.close());
+
+    const { stdout } = await child.output();
+
+    const decoder = new TextDecoder();
+    const data = decoder.decode(stdout).trim().split("\n");
+    assertEquals(data, expected);
+  },
+});
+
 Deno.test({
   name: "process.stdout",
   fn() {

node/testdata/process_stdin.ts

@@ -0,0 +1,11 @@
+import process from "../process.ts";
+
+console.log(process.stdin.readableHighWaterMark);
+
+process.stdin.setEncoding("utf8");
+process.stdin.on("readable", () => {
+  console.log(process.stdin.read());
+});
+process.stdin.on("end", () => {
+  console.log("end");
+});

node/testdata/process_stdin_dummy.txt

@@ -0,0 +1,2 @@
+foo
+bar