UglifyJsPlugin hangs on module building.

When building my application with webpack.optimize.UglifyJsPlugin({}) webpack consistently hangs at around 53% 267/366 build modules. This seamed strange as I would expect it to hang at the optimising chunks stage (if at all).

When I comment https://github.com/webpack/webpack/blob/master/lib/optimize/UglifyJsPlugin.js#L139 I get a successful build. Oddly enough the sources seem to have been both mangled and minified.

Sadly I’m finding it hard to extract any debug information to move any further with this. Is there somewhere in the source I can add some logs to get a better idea of which module in my stack is causing the issue? I’ve tried context.resource but deleting the code in the offending module doesn’t seem to effect the issue at all.

[lazabogdan]

+1 … just lost 6hrs of my life tracking down a similar issue caused by a loader when using webpack -p. The build was just stalling at “build modules” and no error, no timeout, no nothing. Just lovely time tracking it down in a serious dependency tree.

[jamespamplin]

Hi, found the issue that was causing this problem for us. It was a bad HTML template breaking the html-loader / html-minifier. A badly closed quote " in the source, was breaking things. Switching to raw loader worked, allowing me to narrow in on the issue.

When you enable UglifyJsPlugin, it also activates minification in all loaders that support minification (context.minimize). So if you have similar issues when you enable UglifyJsPlugin, or use -p on the CLI, then I suggest you look at potential issues with all your loaders.

I suggest that webpack should implement a timeout for each compiler process so that it can catch hanging plugins, and error accordingly. Ideally, webpack should’ve errored with a timeout such as:

html-loader timed out after 10s processing file: src/templates/bad-template.html