Unable to compile twitter bootstrap with pro version

I just bought pro version of the workbench to be able to compile less files easily, unfortunately I get the following error when trying to compile bootstrap.less : 

Less compiler error:  error: Maximum call stack size exceeded

Thanks for reporting this.  We're still investigating why this error is occurring, but it seems to be triggered by a child element selector that contains a mixin reference where the mixin selector is one of the sub-selectors e.g.

form .clearfix {
  .clearfix()
}

In the latest version of Twitter Bootstrap, this happens in forms.less on line 31.  You can work around it by changing the selector to use a different name e.g.

form .clearfix_workaround {
  // selector body as existing
}

Obviously, the impact of this is that you will need to specify class="clearfix_workaround" instead of class="clearfix" on form elements until we are able to ship you a fix.  Since Twitter Bootstrap uses .clearfix subselectors for several other elements, you may wish to make the same change on lines 162, 438 and 454, even though this isn't necessarily to get it to compile: this will save you having to remember which elements the workaround is applying to.  Alternatively, you may be able to work around it by renaming the .clearfix mixin in mixins.less -- this would require more changes to the Bootstrap .less files to reflect the name change, but should avoid any need to change the HTML files that reference the generated CSS (note I have not tested this).

Thanks again for letting us know about this, and apologies for the inconvenience -- we will try to get you a fix as soon as possible.

Thanks for this amazing reply guys !

Nice hotfix. For minimal impact you 
could also use an alternate classname as follows.
Thanks
Chris
 
mixins.less:line ~7

// Clearfix for clearing floats like a boss h5bp.com/q
.clearfix() {
    .clearfixalt();
}
.clearfixalt() {
  zoom: 1;

forms.less:line ~31

form .clearfix {
  margin-bottom: @baseline;
  .clearfixalt()
}