From 57bb54ea26bef7eab062925364158a4c478062f3 Mon Sep 17 00:00:00 2001
From: Jake Gordon <jakesgordon@gmail.com>
Date: Sun, 12 Apr 2020 14:02:30 -0700
Subject: [PATCH] Ensure --watch mode exits correctly when stdin is closed.
 (#3493)

* Ensure --watch mode exits correctly when stdin is closed.

This is necessary when rollup is used as the front end for an Elixir
Phoenix application. In dev mode, the phoenix watchers run the rollup
command as a child process and the underlying erlang port mechanism
assumes that the child process closes when the parent stdin is
closed. Without this fix the old zombie processes never close and
accumulate as you stop and start in development mode.

This was discussed and fixed in 2017 in the original rollup-watcher
repository:

  * https://github.com/rollup/rollup-watch/issues/30#issuecomment-316468552
  * https://github.com/rollup/rollup-watch/pull/57/files

It appears to then have been removed as a side effect of another change

  * https://github.com/rollup/rollup/pull/2410

Finally, was requested back in a PR that never got merged because of
some doubt around the need to hide it behind a CLI flag

  * https://github.com/rollup/rollup/pull/2653/files

For reference, webpack implements this hidden behind the --watch-stdin
CLI flag.

* Add a test that times out without this change

Co-authored-by: Lukas Taegert-Atkinson <lukas.taegert-atkinson@tngtech.com>
---
 cli/run/watch.ts                              |  2 +-
 test/cli/samples/watch/close-stdin/_config.js |  4 +++
 .../watch/close-stdin/_expected/out.js        |  3 +++
 test/cli/samples/watch/close-stdin/main.js    |  1 +
 test/cli/samples/watch/close-stdin/wrapper.js | 26 +++++++++++++++++++
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 test/cli/samples/watch/close-stdin/_config.js
 create mode 100644 test/cli/samples/watch/close-stdin/_expected/out.js
 create mode 100644 test/cli/samples/watch/close-stdin/main.js
 create mode 100755 test/cli/samples/watch/close-stdin/wrapper.js

diff --git a/cli/run/watch.ts b/cli/run/watch.ts
index 47ae5b873..176220c5f 100644
--- a/cli/run/watch.ts
+++ b/cli/run/watch.ts
@@ -26,9 +26,9 @@ export default async function watch(command: any) {
 
 	onExit(close);
 	process.on('uncaughtException' as any, close);
-	// only listen to stdin if it is a pipe
 	if (!process.stdin.isTTY) {
 		process.stdin.on('end', close);
+		process.stdin.resume();
 	}
 
 	if (configFile) {
diff --git a/test/cli/samples/watch/close-stdin/_config.js b/test/cli/samples/watch/close-stdin/_config.js
new file mode 100644
index 000000000..523753514
--- /dev/null
+++ b/test/cli/samples/watch/close-stdin/_config.js
@@ -0,0 +1,4 @@
+module.exports = {
+	command: 'node wrapper.js main.js --watch --format es --file _actual/out.js',
+	description: 'closes the watcher when stdin closes'
+};
diff --git a/test/cli/samples/watch/close-stdin/_expected/out.js b/test/cli/samples/watch/close-stdin/_expected/out.js
new file mode 100644
index 000000000..d862de816
--- /dev/null
+++ b/test/cli/samples/watch/close-stdin/_expected/out.js
@@ -0,0 +1,3 @@
+var main = 42;
+
+export default main;
diff --git a/test/cli/samples/watch/close-stdin/main.js b/test/cli/samples/watch/close-stdin/main.js
new file mode 100644
index 000000000..7a4e8a723
--- /dev/null
+++ b/test/cli/samples/watch/close-stdin/main.js
@@ -0,0 +1 @@
+export default 42;
diff --git a/test/cli/samples/watch/close-stdin/wrapper.js b/test/cli/samples/watch/close-stdin/wrapper.js
new file mode 100755
index 000000000..0338bd7c9
--- /dev/null
+++ b/test/cli/samples/watch/close-stdin/wrapper.js
@@ -0,0 +1,26 @@
+#!/usr/bin/env node
+
+const stream = require('stream');
+const fs = require('fs');
+const path = require('path');
+
+delete process.stdin;
+process.stdin = new stream.Readable({
+	encoding: 'utf8',
+	read() {
+		return null;
+	}
+});
+
+const outputDir = path.resolve(__dirname, '_actual');
+fs.mkdirSync(outputDir);
+const outputFile = path.resolve(outputDir, 'out.js');
+fs.writeFileSync(outputFile, 'NOT WRITTEN');
+
+const watcher = fs.watch(outputFile, () => {
+	watcher.close();
+	// This closes stdin
+	process.stdin.push(null);
+});
+
+require('../../../../../dist/bin/rollup');