Watchers do not detect specific files

[mvicens]

Taking this Gulp file:

const { watch } = require('gulp');

function css(cb) {
	cb();
}

function js(cb) {
	cb();
}

function defaultTask(cb) {
	watch('src/**/*.css', css);
	watch('src/scripts/index.js', js);
	cb();
}

exports.default = defaultTask;

And, starting from an empty folder src, ...

1. Run Gulp command.
2. Create a CSS file. ✅ It is detected correctly (a "Starting 'css'..." and the appropriate finalization appear in the console).
3. Change the content of this file. ✅ Detected.
4. So, put the specific JS file. ❌ Nothing happens.
5. Change its content. ❌ Nothing.
6. Rerun command (finish and start again).
7. Change the CSS content. ✅ Detected.
8. Change the JS content. ✅ Detected.

Why this behaviour (steps 4 & 5)? Is it a bug, right?

[yocontra]

This should be resolved in v5, but feel free to let me know if not and I'll reopen.

[mvicens]

It makes the same. 😢

[yocontra]

Seems like the issue is watching a specific file (not a glob) that doesn't exist yet, then when it does exist the change isn't being picked up.

[mvicens]

I edited my issue explanation message to clarify more. Please, check it over.