Version 4.0.0 does not reflect less file changes when using gulp-watch

[parapada73]

I am using gulp-watch (5.0.0).
After updating to 4.0.0 today, CSS is generated but the changes are not reflected.
Version 3.5.0 did not have this problem.

Below is the code that uses gulp-watch.

const gulp = require('gulp');
const gulp_watch = require('gulp-watch');
const gulp_messenger = require('gulp-messenger');
const gulp_plumber = require('gulp-plumber');
const gulp_less = require('gulp-less');
const path = require('path');
const beep = require('beepbeep');
const gulp_messenger = require('gulp-messenger');

const gulp_watch_options = {
	useFsEvents: true,
};

let showSuccessMessage = function(pathString){
	pathString = path.resolve(pathString);
	gulp_messenger.success('<%= name %> : maked', {name: pathString});
};

let makeCSS = function(){
	let isError = false;
	
	const sourcePath = path.join(basePath_webroot, 'WEB-INF/_ui-src/responsive/themes/fn/less/style.less');
	const basePath_target = path.join(basePath_webroot, '_ui/responsive/theme-fn/css');
	
	return gulp.src(sourcePath)
		.pipe(gulp_plumber({errorHandler: function(err){
			beep();
			gulp_messenger.error(err);
			isError = true;
			this.emit('end');
		}}))
		.pipe(gulp_less())
		.pipe(gulp.dest('.', {cwd:basePath_target}))
		.on('end', function(){
			if(!isError){
				showSuccessMessage(path.join(basePath_target, 'style.css'));
			}
			
			isError = false;
		});
};

[stephenlacy]

"CSS is generated but the changes are not reflected"
What does that mean?
This only updates the less binary behind the scenes, the less binary does not have anything to do with gulp's sources or files passed through the stream.

[robinparisi]

Same here.

My gulp wach task :

gulp.task('watch', () => {
    bs.init({
        server: {
            baseDir: "./dist",
        },
        open: false
    });

    gulp.watch(['src/**/*', '!src/_assets/**/*'], gulp.series('jekyll:build'));
    gulp.watch('src/_assets/less/**/*', gulp.series('css'));
    gulp.watch('src/_assets/img/**/*', gulp.series('images'));
});

When editing Less files, the task is trigerred:

[Browsersync] 1 file changed (style.css)
[16:37:43] Finished 'css' after 115 ms
[16:37:44] Starting 'css'...

But if I open the dist/style.css file, nothing changes (except for the first watch execution or if I run gulp css manually.

I'm using Gulp 4.0.0 and everything works fine with gulp-less 3.5.0.

[stephenlacy]

So the changes are not reflected to the compiled output if the task is run through a subsequent build when triggered by gulp.watch?

[robinparisi]

Exactly, except for the first run:

• launch gulp watch
• do some changes + save
• css task is run and changes are reflected
• do some changes + save
• css task is run but changes are not reflected
• do some changes + save
• css task is run but changes are not reflected
• restart watch
• do some changes + save
• css task is run and changes are reflected
• do some changes + save
• css task is run but changes are not reflected
• etc...

[stephenlacy]

What happens when you set useFileCache to true in the options?

[robinparisi]

Like this?

.pipe(less({
  useFileCache: true
}))

It doesn't change anything.

[brunofarias]

The same problem happens here

[NikitaAvvakumov]

Almost exactly the same problem here, except it's the changes to @imports that aren't reflected in the generated CSS. My 'watch' task monitors changes to all *.less files and then triggers the 'less' task that uses the main LESS file as the source. Changes made in the main file itself always end up in the CSS but changes in any of the files it imports trigger the 'less' task but the generated CSS remains the same.

[nicolasbettag]

I'm experiencing the same issue! Just downgraded to 3.5.0, now it's running again.

[stephenlacy]

The only update from 3.5.0 to 4.0.0 was upgrading less, which means one of the methods the newer less uses for determining changes is altered.

[seven-phases-max]

one of the methods the newer less uses for determining changes is altered.

Less (its node version) itself does not cache any files (either input or output) between different sessions so the problem is somewhere in between. (More verbose log of the build process would be handy I guess).

[nicolasbettag]

I'm still trying to figure out, where the error is. Mysterious. Maybe there's an error in Gulp 4. It's still kinda buggy.

[stephenlacy]

What is the OS all of you are on?

[NikitaAvvakumov]

@stevelacy macOS 10.13.3 (High Sierra)

[robinparisi]

@stevelacy macOS 10.12.6