From 99ef802c0031af7d0e3313cda60b6fac8471ac06 Mon Sep 17 00:00:00 2001
From: Edy Silva <edigleyssonsilva@gmail.com>
Date: Fri, 18 Jul 2025 01:39:07 -0300
Subject: [PATCH] src,test: fix config file parsing for flags defaulted to true

---
 src/node_config_file.cc              |  4 ++++
 test/fixtures/rc/warnings-false.json |  5 +++++
 test/parallel/test-config-file.js    | 11 +++++++++++
 3 files changed, 20 insertions(+)
 create mode 100644 test/fixtures/rc/warnings-false.json

diff --git a/src/node_config_file.cc b/src/node_config_file.cc
index 1a19465c728ebc..e6c049b4d14f10 100644
--- a/src/node_config_file.cc
+++ b/src/node_config_file.cc
@@ -55,6 +55,10 @@ ParseResult ConfigReader::ProcessOptionValue(
       if (result) {
         // If the value is true, we need to set the flag
         output->push_back(option_name);
+      } else {
+        // Ensure negation is made putting the "--no-" prefix
+        output->push_back("--no-" +
+                          option_name.substr(2, option_name.size() - 2));
       }
 
       break;
diff --git a/test/fixtures/rc/warnings-false.json b/test/fixtures/rc/warnings-false.json
new file mode 100644
index 00000000000000..55ca24aac3a503
--- /dev/null
+++ b/test/fixtures/rc/warnings-false.json
@@ -0,0 +1,5 @@
+{
+  "nodeOptions": {
+    "warnings": false
+  }
+}
diff --git a/test/parallel/test-config-file.js b/test/parallel/test-config-file.js
index 75d0922630cd3a..cc235bfadae146 100644
--- a/test/parallel/test-config-file.js
+++ b/test/parallel/test-config-file.js
@@ -60,6 +60,17 @@ test('should parse boolean flag', async () => {
   strictEqual(result.code, 0);
 });
 
+test('should parse boolean flag defaulted to true', async () => {
+  const result = await spawnPromisified(process.execPath, [
+    '--experimental-config-file',
+    fixtures.path('rc/warnings-false.json'),
+    '-p', 'process.emitWarning("A warning")',
+  ]);
+  strictEqual(result.stderr, '');
+  strictEqual(result.stdout, 'undefined\n');
+  strictEqual(result.code, 0);
+});
+
 test('should throw an error when a flag is declared twice', async () => {
   const result = await spawnPromisified(process.execPath, [
     '--no-warnings',