From 6a0bfb64a843ddc28f6b2e8d4d719df1eec40f36 Mon Sep 17 00:00:00 2001
From: Lukas Taegert-Atkinson <lukas.taegert-atkinson@tngtech.com>
Date: Fri, 31 Dec 2021 08:12:45 +0100
Subject: [PATCH] Do not watch unless --watch is specified explicitly

---
 cli/run/index.ts                              |  3 ++-
 src/utils/options/mergeOptions.ts             | 20 ++++++++++++++-----
 src/utils/options/options.ts                  |  5 ++++-
 .../watch/no-watch-by-default/_config.js      | 12 +++++++++++
 .../samples/watch/no-watch-by-default/main.js |  1 +
 .../no-watch-by-default/rollup.config.js      |  9 +++++++++
 .../watch/no-watch-by-default/wrapper.js      |  5 +++++
 7 files changed, 48 insertions(+), 7 deletions(-)
 create mode 100644 test/cli/samples/watch/no-watch-by-default/_config.js
 create mode 100644 test/cli/samples/watch/no-watch-by-default/main.js
 create mode 100644 test/cli/samples/watch/no-watch-by-default/rollup.config.js
 create mode 100755 test/cli/samples/watch/no-watch-by-default/wrapper.js

diff --git a/cli/run/index.ts b/cli/run/index.ts
index 6ff743c79f8..ed4478fa6d4 100644
--- a/cli/run/index.ts
+++ b/cli/run/index.ts
@@ -1,4 +1,5 @@
 import { MergedRollupOptions } from '../../src/rollup/types';
+import { isWatchEnabled } from '../../src/utils/options/mergeOptions';
 import { getAliasName } from '../../src/utils/relativeId';
 import { loadFsEvents } from '../../src/watch/fsevents-importer';
 import { handleError } from '../logging';
@@ -56,7 +57,7 @@ export default async function runRollup(command: Record<string, any>): Promise<v
 		});
 	}
 
-	if (command.watch) {
+	if (isWatchEnabled(command.watch)) {
 		await loadFsEvents();
 		const { watch } = await import('./watch-cli');
 		watch(command);
diff --git a/src/utils/options/mergeOptions.ts b/src/utils/options/mergeOptions.ts
index 9b92961d4b4..472090b1847 100644
--- a/src/utils/options/mergeOptions.ts
+++ b/src/utils/options/mergeOptions.ts
@@ -13,6 +13,7 @@ import {
 	defaultOnWarn,
 	generatedCodePresets,
 	GenericConfigObject,
+	objectifyOption,
 	objectifyOptionWithPresets,
 	treeshakePresets,
 	warnUnknownOptions
@@ -135,7 +136,7 @@ function mergeInputOptions(
 			'treeshake',
 			objectifyOptionWithPresets(treeshakePresets, 'treeshake', 'false, true, ')
 		),
-		watch: getWatch(config, overrides, 'watch')
+		watch: getWatch(config, overrides)
 	};
 
 	warnUnknownOptions(
@@ -171,8 +172,7 @@ const getObjectOption = (
 	config: GenericConfigObject,
 	overrides: GenericConfigObject,
 	name: string,
-	objectifyValue: (value: unknown) => Record<string, unknown> | undefined = value =>
-		(typeof value === 'object' ? value : {}) as Record<string, unknown> | undefined
+	objectifyValue = objectifyOption
 ) => {
 	const commandOption = normalizeObjectOptionValue(overrides[name], objectifyValue);
 	const configOption = normalizeObjectOptionValue(config[name], objectifyValue);
@@ -182,8 +182,18 @@ const getObjectOption = (
 	return configOption;
 };
 
-const getWatch = (config: GenericConfigObject, overrides: GenericConfigObject, name: string) =>
-	config.watch !== false && getObjectOption(config, overrides, name);
+export const getWatch = (config: GenericConfigObject, overrides: GenericConfigObject) =>
+	config.watch !== false && getObjectOption(config, overrides, 'watch');
+
+export const isWatchEnabled = (optionValue: unknown): boolean => {
+	if (Array.isArray(optionValue)) {
+		return optionValue.reduce(
+			(result, value) => (typeof value === 'boolean' ? value : result),
+			false
+		);
+	}
+	return optionValue === true;
+};
 
 export const normalizeObjectOptionValue = (
 	optionValue: unknown,
diff --git a/src/utils/options/options.ts b/src/utils/options/options.ts
index d6555064c63..cfcf75b9306 100644
--- a/src/utils/options/options.ts
+++ b/src/utils/options/options.ts
@@ -94,6 +94,9 @@ type ObjectOptionWithPresets =
 	| Partial<NormalizedTreeshakingOptions>
 	| Partial<NormalizedGeneratedCodeOptions>;
 
+export const objectifyOption = (value: unknown): Record<string, unknown> =>
+	value && typeof value === 'object' ? (value as Record<string, unknown>) : {};
+
 export const objectifyOptionWithPresets =
 	<T extends ObjectOptionWithPresets>(
 		presets: Record<string, T>,
@@ -117,7 +120,7 @@ export const objectifyOptionWithPresets =
 				)
 			);
 		}
-		return value && typeof value === 'object' ? (value as Record<string, unknown>) : {};
+		return objectifyOption(value);
 	};
 
 export const getOptionWithPreset = <T extends ObjectOptionWithPresets>(
diff --git a/test/cli/samples/watch/no-watch-by-default/_config.js b/test/cli/samples/watch/no-watch-by-default/_config.js
new file mode 100644
index 00000000000..b43ee5fbb19
--- /dev/null
+++ b/test/cli/samples/watch/no-watch-by-default/_config.js
@@ -0,0 +1,12 @@
+const { assertIncludes } = require('../../../../utils');
+
+module.exports = {
+	description: 'does not watch if --watch is missing',
+	command: 'node wrapper.js -c --no-watch.clearScreen',
+	stderr: stderr => assertIncludes(stderr, 'main.js → _actual.js...\ncreated _actual.js in'),
+	abortOnStderr(data) {
+		if (data.includes('waiting for changes')) {
+			throw new Error('Watch initiated');
+		}
+	}
+};
diff --git a/test/cli/samples/watch/no-watch-by-default/main.js b/test/cli/samples/watch/no-watch-by-default/main.js
new file mode 100644
index 00000000000..7a4e8a723a4
--- /dev/null
+++ b/test/cli/samples/watch/no-watch-by-default/main.js
@@ -0,0 +1 @@
+export default 42;
diff --git a/test/cli/samples/watch/no-watch-by-default/rollup.config.js b/test/cli/samples/watch/no-watch-by-default/rollup.config.js
new file mode 100644
index 00000000000..161653a6b43
--- /dev/null
+++ b/test/cli/samples/watch/no-watch-by-default/rollup.config.js
@@ -0,0 +1,9 @@
+export default [
+	{
+		input: 'main.js',
+		output: {
+			file: '_actual.js',
+			format: 'es',
+		},
+	}
+];
diff --git a/test/cli/samples/watch/no-watch-by-default/wrapper.js b/test/cli/samples/watch/no-watch-by-default/wrapper.js
new file mode 100755
index 00000000000..8f733cc8815
--- /dev/null
+++ b/test/cli/samples/watch/no-watch-by-default/wrapper.js
@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+
+process.stdout.isTTY = true;
+process.stderr.isTTY = true;
+require('../../../../../dist/bin/rollup');