Using gulp-ng-annotate with lazypipe inside gulp-watch without triggering tasks still crashes even with plumber. This setup results in a continuous pipe setup resilient against syntax errors with very little overhead.

gulp-watch-ng-annotate-lazypipe-fix.js

var gulp = require('gulp')
var gulpIf = require('gulp-if')
var gulpNgAnnotate = require('gulp-ng-annotate')
var gulpPlumber = require('gulp-plumber')
var gulpWatch = require('gulp-watch')
var lazypipe = require('lazypipe')
var processPipe

gulp.task('watch-annotate', watch)

processPipe = lazypipe()
.pipe(ngAnnotateWithoutCrashingOnSyntaxErrors)

/**
 * Triggers building index.html on start and on file changes.
 */
function watch () {
    gulpWatch('src/**/*.js')
    .pipe(gulpPlumber())
    .pipe(processPipe())
    .pipe(gulp.dest('dest'))
}

/**
 * Catches SyntaxErrors before ngAnnotate gets the chance to break everything.
 *
 * @returns {Pipe}
 */
function ngAnnotateWithoutCrashingOnSyntaxErrors () {
    return gulpIf(function (file) {
            try {
                require(file.path)
            } catch (e) {
                if (e instanceof SyntaxError) {
                    // this is where everything would break down otherwise
                    return false
                }
            }

            return true
        }, gulpNgAnnotate()
    )
}