[Seaside] exceptions while debugging - frozen UI

Colin Putney cputney at wiresong.ca
Thu Apr 10 15:17:11 UTC 2008

On 10-Apr-08, at 7:06 AM, Holger Kleinsorgen wrote:

> - UI is frozen, image is still alive

Hi Holger,

I've run into this myself. I haven't been able to pin down the exact  
cause, but I believe it's something like this: by opening a debugger,  
you are effectively transferring execution of the callback from a  
Seaside process to the UI process. When you step over the method that  
produces an HTTP response, Seaside uses an escape continuation to  
replace the stack of the UI process with the stack of the process that  
was serving the HTTP request. Once the response has been sent to the  
browser, that process exits, leaving you without a UI process.

It's probably not exactly like that, and probably the exact steps are  
different in the different versions of Seaside, but the effect is  
always that the UI process is destroyed when the HTTP response is sent  
out. Fortunately, there's an easy work around. Just press cmd-. to  
create a new UI process and you're fine.


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