Skip to content

watch: strip watch flags from NODE_OPTIONS in child process #62143

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
nodejs-github-bot merged 6 commits into from
Sep 22, 2026
Merged

watch: strip watch flags from NODE_OPTIONS in child process #62143

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
82f7946
watch: strip watch flags from NODE_OPTIONS in child process
marcopiraccini Mar 7, 2026
cb08852
watch: strip watch flags from NODE_OPTIONS in child process
marcopiraccini Mar 8, 2026
d53aea2
fixup
marcopiraccini Mar 8, 2026
e78ac78
fixup
marcopiraccini Mar 8, 2026
7727a39
fixup after review
marcopiraccini Apr 9, 2026
9def55c
test: skip --watch NODE_OPTIONS test without NODE_OPTIONS support
marcopiraccini May 6, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Next Next commit
watch: strip watch flags from NODE_OPTIONS in child process 
Signed-off-by: marcopiraccini <marco.piraccini@gmail.com>
  • Loading branch information
@marcopiraccini
marcopiraccini committed May 26, 2026
commit 82f794613cd43fcd3a887ec6fd044c06368ff447
28 changes: 28 additions & 0 deletions lib/internal/main/watch_mode.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ const {
ArrayPrototypePush,
ArrayPrototypePushApply,
ArrayPrototypeSlice,
RegExpPrototypeSymbolSplit,
StringPrototypeStartsWith,
} = primordials;

Expand Down Expand Up @@ -78,6 +79,32 @@ for (let i = 0; i < process.execArgv.length; i++) {

ArrayPrototypePushApply(argsWithoutWatchOptions, kCommand);

const kNodeOptions = process.env.NODE_OPTIONS;
let cleanNodeOptions = kNodeOptions;
if (kNodeOptions != null) {
const nodeOptionsArgs = [];
const parts = RegExpPrototypeSymbolSplit(/\s+/, kNodeOptions);

@Renegade334 Renegade334 Mar 8, 2026 •
edited
Loading

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ultimately, this sort of approach isn't robust enough.

$ mkdir 'test for --watch parsing'
$ echo 'console.log("hi!")' > 'test for --watch parsing/test.cjs'
$ NODE_OPTIONS='--require "./test for --watch parsing/test.cjs"' node -p 'process.env.NODE_OPTIONS.split(" ")'
hi!
[ '--require', '"./test', 'for', '--watch', 'parsing/test.cjs"' ]
                                  ^^^^^^^

I suspect this is going to need to interact with the options parser in some way.

@marcopiraccini marcopiraccini Mar 8, 2026

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good catch.
Thinking about it, maybe adding a C++ binding that exposes ParseNodeOptionsEnvVar to JS would be more robust (being the same parser to interpret NODE_OPTIONS, in my undersanding) and then finltering out watch flags. Will amend this PR.

@marcopiraccini marcopiraccini Mar 8, 2026

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@Renegade334 PTAL

for (let i = 0; i < parts.length; i++) {
const part = parts[i];
if (part === '') continue;
if (part === '--watch' ||
part === '--watch-preserve-output' ||
StringPrototypeStartsWith(part, '--watch=') ||
StringPrototypeStartsWith(part, '--watch-preserve-output=') ||
StringPrototypeStartsWith(part, '--watch-path=') ||
StringPrototypeStartsWith(part, '--watch-kill-signal=')) {
continue;
}
if (part === '--watch-path' || part === '--watch-kill-signal') {
// These flags take a separate value argument
i++;
continue;
}
ArrayPrototypePush(nodeOptionsArgs, part);
}
cleanNodeOptions = ArrayPrototypeJoin(nodeOptionsArgs, ' ');
}

const watcher = new FilesWatcher({ debounce: 200, mode: kShouldFilterModules ? 'filter' : 'all' });
ArrayPrototypeForEach(kWatchedPaths, (p) => watcher.watchPath(p));

Expand All @@ -93,6 +120,7 @@ function start() {
env: {
...process.env,
WATCH_REPORT_DEPENDENCIES: '1',
NODE_OPTIONS: cleanNodeOptions,
},
});
watcher.watchChildProcessModules(child);
Expand Down
33 changes: 33 additions & 0 deletions test/sequential/test-watch-mode.mjs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -943,4 +943,37 @@ process.on('message', (message) => {
await done();
}
});

it('should strip all watch flags from NODE_OPTIONS in child process', async () => {
const file = createTmpFile('console.log(process.env.NODE_OPTIONS);');
const nodeOptions = [
'--watch', // bare boolean
'--watch=true', // boolean with =value
'--watch-path=./src', // string with =value
'--watch-path', './test', // String with space-separated value
'--watch-preserve-output', // bare boolean
'--watch-preserve-output=true', // boolean with =value
'--watch-kill-signal=SIGKILL', // string with =value
'--watch-kill-signal', 'SIGINT', // String with space-separated value
'--max-old-space-size=4096',
'--no-warnings',
].join(' ');
const { done, restart } = runInBackground({
args: ['--watch', file],
options: {
env: { ...process.env, NODE_OPTIONS: nodeOptions },
},
});

try {
const { stdout, stderr } = await restart();

assert.strictEqual(stderr, '');
const nodeOptionsLine = stdout.find((line) => line.includes('--max-old-space-size'));
assert.ok(nodeOptionsLine);
assert.strictEqual(nodeOptionsLine, '--max-old-space-size=4096 --no-warnings');
} finally {
await done();
}
});
});