Strip debug flags from subprocess NODE_OPTIONS

Fixes #14

Author: sindresorhus

subprocess.js

@@ -31,14 +31,19 @@ export default function makeSynchronous(function_) {
 			}
 		`;
 
+		const env = {...process.env, ELECTRON_RUN_AS_NODE: '1'};
+
+		// Prevent debugger flags from the parent from forcing the child to open a debug port.
+		env.NODE_OPTIONS &&= env.NODE_OPTIONS
+			.split(/\s+/)
+			.filter(option => !/^--(?:inspect|debug)/.test(option))
+			.join(' ');
+
 		const {error: subprocessError, stdout, stderr} = childProcess.spawnSync(process.execPath, ['--input-type=module', '-'], {
 			input,
 			encoding: 'utf8',
 			maxBuffer: HUNDRED_MEGABYTES,
-			env: {
-				...process.env,
-				ELECTRON_RUN_AS_NODE: '1',
-			},
+			env,
 		});
 
 		if (subprocessError) {

test.js

@@ -69,3 +69,23 @@ for (const {type, makeSynchronous} of [
 		}
 	});
 }
+
+test.serial('[childprocess] strips debug flags from NODE_OPTIONS', t => {
+	const function_ = makeSynchronousByChildprocess(async () => {
+		const {default: inspector} = await import('node:inspector');
+		return {inspectorUrl: inspector.url()};
+	});
+
+	const originalNodeOptions = process.env.NODE_OPTIONS; // eslint-disable-line n/prefer-global/process
+	process.env.NODE_OPTIONS = '--inspect=127.0.0.1:0'; // eslint-disable-line n/prefer-global/process
+	try {
+		const {inspectorUrl} = function_();
+		t.is(inspectorUrl, undefined);
+	} finally {
+		if (originalNodeOptions === undefined) {
+			delete process.env.NODE_OPTIONS; // eslint-disable-line n/prefer-global/process
+		} else {
+			process.env.NODE_OPTIONS = originalNodeOptions; // eslint-disable-line n/prefer-global/process
+		}
+	}
+});