Fatal error: Cannot overwrite a zero-length range – use appendLeft or prependRight instead

[Richard-Walton]

I've recently upgraded my brfs package to 1.50 which includes the latest source map changes implemented in this module.

Unfortunately my build is now failing with the following error:

Fatal error: Cannot overwrite a zero-length range – use appendLeft or prependRight instead

After some digging around I tracked down the issue to this line: https://github.com/browserify/static-module/blob/master/index.js#L64

In my case s.offset === 0 (creating the aforementioned zero-length range error).

I have discovered a workaround for the issue. Originally my code looked like this:

var fs = require('fs')
    , anotherModule = require('anotherModule')
    , x = true;
...
var file = fs.readFileSync(....);

Moving the require('fs') to it's own line fixes the problem:

var fs = require('fs');
var anotherModule = require('anotherModule')
    , x = true;
...
var file = fs.readFileSync(....);

I wonder if the removal of the require('fs') calls during the browserify build process causes this error?

My initial thoughts to fix this issue would involve adding a guard against s.offset being 0... I'm happy to open a PR if you think this is a viable solution.

[Richard-Walton]

@goto-bus-stop Any thoughts?

[goto-bus-stop]

oh crap, thanks. adding a check for s.offset and then using one of the append or prepend methods instead sounds good to me!

[goto-bus-stop]

Oops, I committed on the wrong branch, meant to open a PR for that instead. If CI comes back green I'll release. Thanks for the detailed report!

[goto-bus-stop]

:package: 2.2.2

[Richard-Walton]

Thanks @goto-bus-stop - I ended up getting stuck thinking about how to write a test for the change... looks like it wasn't needed! Sorry I didn't get around to opening a PR for you.

Thanks again

[goto-bus-stop]

no worries! I changed an existing test to also generate source maps, which triggered the error. :)