I just ran into the same problem.
I am instantiating a SoapServer with a WSDL file. When calling a method not in the WSDL the SoapServer dies with a fatal error, instead of returning a SoapFault. After disabling xdebug everything works as it should.

Is this going to be fixed?

this is still an issue

We are also having this issue.

It looks like the problem is that the soap extension registers its own zend_error_cb which checks if the error was caused by SOAP and if so, it converts the errors to exceptions. Xdebug also registers its own zend_error_cb and ignores the old_error_cb (except when disabling or destructing). It looks like the fix needed is to call the old_error_cb first and then to do the xdebug stuff. Or somehow make sure that Xdebug modifies the zend_error_cb before soap.

I can't detect very easily whether SOAP is in use, and chaining is also not possible as the old error handler already shows the warning. I added a hack that should prevent Xdebug from using its error handler in case SOAP is in use (by checking for the HTTP_SOAPACTION $_SERVER variable. This seems to alleviate the issue for me. I added this "hack" in Xdebug CVS (HEAD only).